Hubble Space Telescope TrailHubble Space Telescope Trail
Maybe a boring picture, but perhaps less so when you realize the bright streak is the Hubble Space Telescope (HST) through my bigger telescope. This wasn't just a coincidence, but carefully planned. HST mostly stays very low in the sky from my latitude when visible at all, but thanks to SkySafari software I knew that there would be a more favorable HST pass that I had the possibility to capture on a mostly clear evening at Yellowwood State Forest.

I wasn't certain how precise the calculations in the software would be, but the location and timing turned out to be dead on as predicted. Kinda like a solar eclipse, you have to be at the right place at the right time, looking in the right direction.

The background image was from 4 minutes of exposure, while it took about 3 seconds for HST to cross the 41 arcminute wide field, at about 16º altitude. There are at least three faint galaxies visible in the image, though perhaps not in this small version.

GSO 8" f/8 RC OTA, ZWO ASI294MC Pro cooled color CMOS camera, 120gain, -15ºC, IDAS DTD light pollution filter, Losmandy GM811G mount, ZWO EAF autofocuser, Askar off-axis guider, ZWO ASI174MM Mini guide camera, ZWO ASIAir Plus controller. Processed in Astro Pixel Processor, Lightroom, Photoshop.

#hubblespacetelescope #astrophotography

I wasn't certain how precise the calculations in the software would be, but the location and timing turned out to be dead on as predicted. Kinda like a solar eclipse, you have to be at the right place at the right time, looking in the right direction. In this case, with a field of view of only 41 arcminutes, the precision was important.

The background image was from 4 minutes of exposure, while it took about 3 seconds for HST to cross the field, at about 16º altitude. There are at least three faint galaxies visible in the image, though perhaps not in this small version.

Tech details: GSO 8" f/8 RC OTA, ZWO ASI294MC Pro cooled color CMOS camera, 120gain, -15ºC, IDAS DTD light pollution filter, Losmandy GM811G mount, ZWO EAF autofocuser, Askar off-axis guider, ZWO ASI174MM Mini guide camera, ZWO ASIAir Plus controller. Processed in Astro Pixel Processor, Lightroom, Photoshop.

Supernova 2024bch in Galaxy NGC 3206Supernova 2024bch in Galaxy NGC 3206
One of the personal projects I've been working on for a while is photographing supernovae. These are cosmic events in which a star explodes, blowing itself apart and scattering its contents into space. They're so bright they can be recorded from vast distances, but they only appear to us as faint stars. I inadvertently shot the same object a few months apart. On the left is the image I made in February when the supernova was so bright it outshone the bright central core of its host galaxy, NGC 3206, 62 million light-years away. At right is another image I made in June, forgetting I'd done so before. But I'm glad I was able to get a second image when I did because it shows how the supernova changed in a relatively short time, becoming much fainter and redder.

Each image is a composite of 12 5-minute exposures (1 hour total).
GSO 8" f/8 RC OTA, Losmandy Astronomical GM811G mount
ZWO ASI294MC Pro cooled color CMOS camera
ZWO EAF autofocuser
auto-guided, Askar off-axis guider, ZWO ASI174MM Mini guide camera
ZWO ASIAir Plus controller
Processed in Astro Pixel Processor, Adobe Photoshop Lightroom, Adobe Photoshop

#astrophotography, #deepsky, #supernova

One of the personal projects I've been working on for a while is photographing supernovae*. These are cosmic events in which a star explodes, blowing itself apart and scattering its contents into space. They're so bright they can be recorded from vast distances, but appear to us only as faint stars. I inadvertently shot the same object a few months apart. On the left is the image I made in February when the supernova was so bright it outshone the bright central core of its host galaxy, NGC 3206, 62 million light-years away. At right is another image I made in June, forgetting I'd done so before. But I'm glad I was able to get a second image when I did because it shows how the supernova changed in a relatively short time, becoming much fainter and redder.

Each image is a composite of 12 5-minute exposures (1 hour total).
GSO 8" f/8 RC OTA, Losmandy Astronomical GM811G mount
ZWO ASI294MC Pro cooled color CMOS camera
ZWO EAF autofocuser
auto-guided, Askar off-axis guider, ZWO ASI174MM Mini guide camera
ZWO ASIAir Plus controller
Processed in Astro Pixel Processor, Adobe Photoshop Lightroom, Adobe Photoshop

*Supernovae is the plural form of supernova, as usually used by astronomers, though some people use "supernovas" as more colloquial.

Snake River Overlook, Grant Teton National Park, Wyoming, 2011Snake River Overlook, Grant Teton National Park, Wyoming, 2011 But of course there are many differences between our results (aside from the media: digital SLR vs. large-format camera, film, and chemical darkroom; and the fact that I cannot approach Adams's skill): I made a panoramic view to capture more of the Teton range, but part of the Snake River is obscured by trees at lower left. It appears that Adams had a higher viewpoint -- he often used a tall tripod and a platform on his car (https://www.instagram.com/anseladams/p/C0HXRTtL11i/), so was several feet higher than I could get.

While I tried to get a lot of detail and contrast in the processed image, Adams's version is rendered much darker for dramatic effect. I've added my color version for comparison. Guess I prefer the black&white that highlights the forms and tonalities of the landscape as opposed to the somewhat blah colors. (This was processed in Adobe Photoshop Lightroom combined from a panorama sequence of four vertical frames, each comprising several bracketed exposures in HDR.)

Snake River Overlook, Grant Teton National Park, Wyoming, 2011Snake River Overlook, Grant Teton National Park, Wyoming, 2011 Adams discouraged photographers from trying to find his tripod holes, preferring that folks find their own compositions and style, But I think it can be an instructive exercise to help understand why a particular viewpoint can result in a more powerful composition. In this case, the curves of the river lead our eyes toward the mountains (more so in Adams's cropped view) and the juxtaposition of the foreground trees, mountains, and cloudscape create a pleasing balance.

#anseladams, #blackandwhite

Given some excitement over the currently fairly bright comet C/2022 E3 (ZTF), popularly known as the Green Comet, I was reminded that almost a half century ago, another comet, Kohoutek (currently designated C/1973 E1) was a sensation in late 1973 and into 1974. Early predictions were that it would become very bright near its close encounter with the Sun (perihelion). Media reports talked about the 'comet of the century!' Of course as these things happen, those predictions didn't come to pass, but it was still one of the brighter comets at that time.

I was an undergraduate astronomy major at Indiana University then so very engaged. I even managed to get an image of it using the old 10-inch astrograph (photographic telescope) that the IU Astronomy Department operated at Goethe Link Observatory near Mooresville, Indiana, mostly for asteroid observations (no longer there, alas). This photographic negative was on an 8"x10" glass plate that I still have after all this time (though it suffered a small crack at some point).

Unfortunately I did not record the date of observation, exposure time, etc. (no automatic metadata on analog media). But through the magic of software, I was able to reverse-engineer it. From a digital scan of the plate, the amazing online resource astrometry.net solved the coordinates (R.A. 23h 53m 54s, Dec. +02° 01' 34") and equally amazing JPL Horizons generated an ephemeris (list of celestial coordinates) that matched that position on January 24, 1974.

In addition to a basic structural and ornamental construction material, limestone is ideal for carving because it's relatively soft but also fine-grained and uniform so can retain intricate details. It certainly takes a skilled artisan to execute a fine carving, and there are many examples on the IU campus, including traditional, classical architectural features as well as many whimsical ornaments and the occasional quotation.

One of my (many) personal photography projects/assignments is to document the limestone carvings on the IU campus. These are a few of my favorite examples. 

Maxwell Hall, Indiana UniversityMaxwell Hall, Indiana University

Limestone Carving, Indiana University Bloomington CampusLimestone Carving, Indiana University Bloomington Campus
Maxwell Hall, one of the oldest, coolest buildings on campus, is part of the central quadrangle and one of the most interesting architectural gems, including a wealth of detailed carving incorporated into the ornate structure. A group of whimsical bat grotesques adorn the roof. (Grotesques are distinct from gargoyles, which are more functional, channelling water away from the roof). 

A few owls are scattered around campus, appropriate for academics as a traditional symbol of learning and wisdom. These examples also demonstrate the varied carving and architectural styles, which span many decades, including earlier Italianate styles through Art Deco and more modern eras. At first glance I thought the rightmost owl looked more like a rather sinister human face. 

ClefsClefs
Stone carvings at Merrill Hall, Jacobs School of Music, Indiana University, Bloomington

These symbols are pretty familiar, a treble and bass clef that adorn the original music building, Merrill Hall, home of the acclaimed IU Jacobs School of Music. 

Stannous FluorideStannous Fluoride
https://www.myiu.org/stories/pride-and-tradition/true-or-false-myths-of-iu-fluoride/ Appropriately, symbols of all the chemical elements adorn The Chemistry Building, but a few are more obscure. One of these is the chemical symbol SnF2 on the Chemistry building. This is the formula for a compound of tin (Sn) and fluorine (F), tin fluoride or stannous fluoride as it's commercially known, the compound in toothpaste that helps prevent cavities. Why would this be chiseled in stone on this building? It turns out that it was a couple of researchers at Indiana University who first developed and patented a safe and effective toothpaste formulation containing fluoride, after it had been shown effective against tooth decay. The patent was sold to Proctor and Gamble who in the 1960s created Crest, the first toothpaste to incorporate fluoride. There's a myth that the construction of another building on campus, Ballantine Hall was funded from the proceeds of Crest toothpaste. The reality is rather that the royalties from the patent were used to establish the Oral Health Research Institute at the IU School of Dentistry. 
(https://www.myiu.org/stories/pride-and-tradition/true-or-false-myths-of-iu-fluoride/)

On the east wall of Simon Hall, a newer multidisciplinary science building are carvings adorning the windows. These represent six organisms commonly used in biology research: E. coli bacterium, mushroom, fruit fly, mouse, ear of maize and paramecium. In between is a sequence of letters representing part of the genetic code of mouse DNA.
 

Even more obscure perhaps are the symbols HΨ and EΨ (with the greek capital letter Psi, coincidentally similar to the Indiana University logo) also on the Chemistry Building. These are part of one formulation for what's known as the Schrödinger Equation, a key component of quantum mechanics, one of the basic fields of modern physics and therefore fundamental to chemistry too. 

There are many more examples of interesting, unique limestone carving at IU. You can see more in the IU Bloomington gallery.

Crescent Venus in DaylightCrescent Venus in daylight, a composite of 30 frames combined in Photoshop (in median mode), which sharpens the image by averaging out the variations in the individual frames mostly due to the turbulence of the air. 30 1/1000 sec. exposures, Explore Scientific 107mm f/7 refractor, ASI294MC camera, dual narrow-band filter, iOptron CEM25P mount, ASIAir controller, processed in Astro Pixel Processor and Lightroom, and combined in Photoshop.

This was something a little different and a bit of a challenge: catching the crescent of the planet Venus in daylight. It's easy to spot Venus at dusk or dawn because it's the brightest planet in the sky. But during daylight, the Sun makes the sky so bright that it's very difficult to see Venus. And it's especially challenging during the crescent phase, when relatively little of the planet's visible disk is illuminated, because of the Solar System geometry; at this phase, Venus is between the Earth and the Sun so we are seeing only the rim of the planet illuminated. 

Nevertheless, if you know where to look, and very importantly can avoid looking at the Sun, you can certainly see Venus in the daytime, especially with binoculars or a telescope. And it's a large enough and close enough, the closest planet to Earth and our near twin in size, it resolves into a visible disk with enough magnification.

Since I had the telescope all set up and aligned from shooting overnight, I thought I'd try pointing at Venus the next day. I wasn't sure the pointing with my telescope and mount was good enough to get Venus in the field of the camera, but it did work. 

The still image above is a composite of 30 frames, processed in Astro Pixel Processor and combined in Photoshop using a median algorithm, which sharpens the image by averaging out the variations in the individual frames, mostly due to the turbulence of the air.

Crescent Venus in DaylightVideo of the crescent Venus in daylight.
The atmospheric distortion is quite obvious in this little real-time video, taken with the same equipment. It is more pronounced during the day when temperature differences in the air are greatest from heating by the Sun. Fortunately, it usually settles down at night, but is still there and blurs any images of the sky (and the reason to put telescopes in space, above the atmosphere). 

The still image is a composite of 30 1/1000 sec. exposures, Explore Scientific 107mm f/7 refractor, ZWO ASI294MC Pro camera, dual narrow-band filter (to reduce the light level), iOptron CEM25P mount, ASIAir controller, processed in Astro Pixel Processor and Lightroom, and combined in Photoshop. The video was also made with the ASI294MC camera.

Lunar Eclipse 19 November 2021Partial lunar ecliopse, 19 November 2021, a composite of frames to capture the large range of brightness from the slice of sunlit Moon's limb, the much darker majority of the Moon's surface in Earth's shadow and a much longer exposure for the background stars made during maximum eclipse.

The photo above attempts to capture what I saw. While in the naked eye view the Moon seemed more luminous, we see much more detail in the photo since it was taken with a small telescope to provide some magnification. This was composed from three separate exposures: one to capture detail in the darkest portion of the Moon at maximum eclipse (1/2 second, ISO 800), a shorter exposure to capture detail in the sunlit sliver (1/500 second, ISO 100), and a much longer exposure to capture the stars in the background sky (30 seconds, ISO 800).

I wanted better visualize the Moon passing through Earth's shadow, so I put together another illustration from a sequence of images showing the Moon moving across the sky.

Lunar Eclipse SequenceA sequence of frames of the 19 November 2021 lunar eclipse. The images have been arranged in their true relative position as the moon travels across the sky and through the Earth's shadow. Different exposures have been used to compensate for the very large change in the Moon's brightness as it passes in and out of the shadow. Without this view, it's always a little hard for me to visualize the relationship of the Moon and Earth's shadow. You may also notice a couple of other things here: the shadow is round (surprise, the Earth is not flat!), and it's as large as the Earth, about four times the diameter of the Moon.

I had taken many different exposures throughout the eclipse because I wasn't sure what the best exposure would be, and the brightness difference is very large, from the bright sunlit side to the darker shadowed side of the Moon; and the camera's automatic exposure doesn't work very well for this sort of subject with mostly black and a little very bright subject. You can see this large difference in the frames just around the center fo the sequence. In the central frame, we see a lot of detail in the shadow, but the bright edge is quite saturated with no detail. In the frames on either side of the center, there is minimal detail in the shadow but more detail in the sunlit portion.

Here's one more result from this long, cold night of Moon watching. I took a time-lapse sequence of the entire eclipse, from before the Moon entered the penumbra (the outer, lighter transition shadow) until after the eclipse, just before dawn. This allowed me to select the best frames for the shadow sequence. And I got some very good images of the full Moon just before the eclipse started. Here's the uneclipsed full Moon in all its glory, pretty much how I see it, except with more detail compared to a naked eye view.
Full MoonThe full Moon taken just before the lunar eclipse on 19 November 2021.

I have made some adjustments in post-processing to bring out the details in the brighter and darker parts of the Moon. Note that it appears quite color-neutral. The Moon's rocks are nearly gray, as the color photos from the Apollo missions beautifully demonstrated. They are also actually quite dark, composed largely of volcanic basalt, but we see it as very bright since it's against the dark sky.

But the rocks are not entirely without color. In this second version I cranked up the color saturation in post-processing (using the Vibrance and Saturation adjustments in Lightroom). Now we can see some of those subtle color differences, which I think are real rather than effects of the camera sensor or processing. I'll leave it up to others to comment on how this might relate to the difference in the composition of the minerals.

Full Moon color-enhancedThe full Moon taken just before the lunar eclipse on 19 November 2021. The color has been enhanced to show differences in minerals on various parts of the Moon's surface.

All of these images were made with a Nikon Z 6 mirrorless camera, Explore Scientific FCD100 102mm aperture, f/7 refracting telescope, mounted on an iOptron CEM25P drive. The exposure sequences were controlled by the in-camera intervalometer with brackets of 9 frames in 1-stop increments every 5 minutes.

I hope it's just as clear for the next lunar eclipse, coming just around the corner in May 2021. I've learned a lot every time I watch and photograph an eclipse. But perhaps even more important, I enjoy these events for their awesome, natural beauty.

I had set up a Nikon D850 DSLR with a wide-angle lens (14-24mm f/2.8 at 20mm) on an iOptron SkyGuider Pro tracker shooting a time-lapse of 60-second exposures centered toward the shower radiant in the constellation Perseus. Out of over 500 frames, 15 or so contained meteors, some very faint, others quite prominent, amid the usual satellites and aircraft. Meanwhile I was also shooting some deep sky targets with a ZWO ASI294MC Pro (cooled color CMOS) camera and Nikon telephoto lens (200-500mm f/5.6 at 500mm) mounted on an iOptron CEM25P drive. Since the conditions were fairly good, I stayed all night, catching a couple of hours sleep in my tent while the cameras kept shooting, though by the wee hours of the morning, the others had left.

Perseid Meteor ShowerThe Perseid meteor shower from Yellowwood State Forest, Brown County, Indiana. A composite of about 50 frames combined in Starry Sky Stacker and further processed in Adobe Lightroom. 15 frames containing meteors were individually added in Adobe Photoshop. Note the Northern Milky Way running through the frame, and the Andromeda Galaxy (M31) at lower right. Nikon D850, 14-24mm f/2.8 @20mm, f/1.8, 60 second exposures, f/2.8, ISO 800, iOptron SkyGuider Pro tracker, Pluto Trigger intervalometer. Processed in Starry Sky Stacker, Lightroom, and Photoshop.
The Perseid meteor shower from Yellowwood State Forest, Brown County, Indiana. A composite of about 50 frames combined in Starry Sky Stacker and further processed in Adobe Lightroom. 15 frames containing meteors were individually added in Adobe Photoshop. Note the Northern Milky Way running through the frame, and the Andromeda Galaxy (M31) at lower right. Nikon D850, 14-24mm f/2.8 @20mm, 60 second exposures, f/2.8, ISO 800, iOptron SkyGuider Pro tracker, Pluto Trigger intervalometer. Processed in Starry Sky Stacker, Lightroom, and Photoshop.
 

The Andromeda Galaxy, M31M31, The Andromeda Galaxy 30 frames, 180 sec. each, ZWO ASI294MC Pro (cooled color CMOS) camera, Nikon telephoto lens (200-500mm f/5.6 at 500mm), and UV/IR cut filter, mounted on an iOptron CEM25P drive, auto-guiding and exposures using an ASIAir controller. Processed in Astro Pixel Processor and Adobe Lightroom.
M31, The Andromeda Galaxy. 30 frames, 180 sec. each, ZWO ASI294MC Pro (cooled color CMOS) camera, Nikon telephoto lens (200-500mm f/5.6 at 500mm), and UV/IR cut filter, mounted on an iOptron CEM25P drive, auto-guiding and exposures using an ASIAir controller. Processed in Astro Pixel Processor and Adobe Lightroom.

The Pleiades Star ClusterM45, the Pleiades open cluster. 20 frames, 180 sec. each, ZWO ASI294MC Pro (cooled color CMOS) camera, Nikon telephoto lens (200-500mm f/5.6 at 500mm), and UV/IR cut filter, mounted on an iOptron CEM25P drive, auto-guiding and exposures using an ASIAir controller. Processed in Astro Pixel Processor and Adobe Lightroom.
M45, the Pleiades open cluster. 20 frames, 180 sec. each, ZWO ASI294MC Pro (cooled color CMOS) camera, Nikon telephoto lens (200-500mm f/5.6 at 500mm), and UV/IR cut filter, mounted on an iOptron CEM25P drive, auto-guiding and exposures using an ASIAir controller. Processed in Astro Pixel Processor and Adobe Lightroom.

Nova Cas 2021A nova in the constellation Cassiopeia, along with an open star cluster, M52 and a star-forming nebula, NGC 7635, the Bubble Nebula.

I managed to catch a nova the other night! No, not the terrific PBS science program (which I do try catch as often as possible), but a star that suddenly brightened and was first observed a few days before. I was able to photograph the nova among a lot of other stars and a couple of other interesting features of the night sky. More about that later. 

But what's a nova? Nova is the Latin word for "new" and was used long ago to describe stars appearing in the sky for the first time. Later when astronomers were able to study the light from some of these stars in more detail they found that they weren't actually new, but stars that brightened dramatically in a short time so we could see them from much farther away. This particular one, known as Nova Cas 2021 or V1405 Cas was discovered in the constellation Cassiopeia (Cas). It is now bright enough to see in binoculars and photograph with modest equipment. It also shares the view with an open cluster of stars, Messier 52 (M52), at top center, and a nice star-forming nebula, NGC 7635, known as the Bubble Nebula for the interstellar cavity being blown by a bright, young star, at lower right.

The nova is near the center, similar in brightness to a few nearby stars, identified in the next image with their brightness in astronomers' magnitude scale (larger numbers indicate fainter light). All of the stars in this image are fainter than we can see with the naked eye. But a composite of several long exposures with a sensitive camera and moderately large lens show a lot of much fainter objects. Before the outburst, the star was very much fainter but was observed and catalogued as CzeV3217, a special kind of binary star known as a W UMa-type eclipsing variable, some 5,500 light years away.

Nova Cas 2021 (annotated)A nova in the constellation Cassiopeia, along with an open star cluster, M52 and a star-forming nebula, NGC 7635, the Bubble Nebula.

By studying spectra (the distribution of the light across colors/wavelengths) and the light curve (the change in brightness over time), astrophysicists can classify novae (the Latin plural of nova) into different types. Nova Cas turns out to be a "classical nova" in which one of the stars in a close binary system (a pair of stars orbiting each other) transfers some of its mass to its white dwarf star companion, which eventually results in a tremendous nuclear explosion that we can see across the galaxy. A white dwarf is a star that has used up all its original fuel so nuclear fusion reactions in its core have stopped and has contracted to a very small fraction of its original size, and is producing light from the heat generated by the compression of its remaining material by the tremendous gravitation.

A nova is a very energetic explosion, but puny compared to the catastrophic event known as a supernova in which an entire star can be blown apart. Supernovae can be so bright they outshine the entire galaxy in which they reside, and can be seen to the farthest reaches of the universe. But that's another whole story.

Here's an article from Sky & Telescope with more information about the nova: https://skyandtelescope.org/astronomy-news/observing-news/bright-nova-erupts-in-cassiopeia/.

Tech: ZWO ASI294MC Pro camera, Nikon 200-500mm f/5.6 lens @500mm, 15x60sec. exposures, iOptron CEM25P drive, ASIAir controller, processed in Astro Pixel Processor and Lightroom.

Frozen Bubble Triptych

Not everyone agrees with me but I think there are plenty of things to appreciate about winter. I like the crisp, clear air, stark, snowy landscapes dramatically different from other seasons, and ice on waterways. One of the amazing things I learned about not long ago is how soap bubbles can freeze into amazing patterns of ice crystals. It does have to be very cold for this to work, which doesn't happen very often here in Southern Indiana. But this winter we've had a stretch of lows in the teens and single digits, so it was time to try my hand. The photos above are the best results I've had so far but of course there's room for improvement. My first attempts weren't nearly so good; there's always a learning curve.

A few folks have asked how to do this so I thought I'd share my experience. I found several resources online as a starting point (one is https://www.wikihow.com/Make-Bubble-Solution), and experimented a bit. You can use prepared bubble solution, which may not be so easy to find in winter, but it's pretty easy to make your own. Here's one simple recipe I mixed together in a jar and worked pretty well:

1 part (1 tbsp) glycerin (found at the drugstore in the beauty aisle — used as a skin moisturizer)
4 parts (4 tbsp) dish soap (I used Ivory since it's clear and not overly concentrated like Dawn Ultra)
16 parts (16 tbsp = 8 oz.) water

Some recipes substitute corn syrup or sugar for the glycerin.

To blow the bubbles it's best to not use your breath as the warmth can slow the bubbles' freezing. I glued a straw to a hole drilled in the cap of an empty water bottle, dipped the straw into the bubble solution and very gently squeezed the bottle to blow the bubbles and try to place them on a surface to photograph. The bubbles are extremely fragile; a breath of breeze or touching them to a surface can break them. But eventually some will stay. How fast they freeze depends on the temperature. The first time I tried it was below 10ºF and they did freeze fast. The next time it was in the teens and they still froze quite fast. 

I wasn't able to blow very large bubbles, which may depend on the thickness of the solution, size of the straw, etc. They were about 1-1/2 inches in diameter. I used a macro lens (105mm) on a Nikon D850 on a tripod, getting close enough to nearly fill the frame. I used a small aperture, f/14 to maximize the depth of field (range of the subject in focus). The bright sun provided plenty of light and some nice highlights, keeping the shutter speeds high (1/400 sec.) to avoid any motion blur.

Finally, it was fun just to watch the process of freezing, seeing those amazing crystals forming on the surface of the bubbles. I haven't made an actual video yet, but I was able to take a series of still frames and put together a little video of one of the bubbles. Though it's from stills, this is close to real time — the freezing happens pretty fast at 14º! (The video repeats three times but you can always replay it.)

TreeptychMcCormick's Creek State Park, Owen County, Indiana

I might have liked sunshine to have the sparkly look on the ice and powdery snow, but the overcast provided very even, low-contrast illumination. In winter, with the trees bare and especially with snow cover there's very little color in the landscape, so a black & white treatment of these photos enables heightening the contrast and highlighting the forms in nature.

Ice, McCormick's CreekMcCormick's Creek State Park, Owen County, Indiana Sometimes it's the smaller details that catch the eye: I love these little stalactites of ice that form along the edges of streams, contrasting with the textures of the snow above and moving water below.

McCormick's Creek State Park, Owen County, Indiana Here's a serendipitous result. Not sure how it happened, wasn't intentional; but pretty cool nevertheless. I know I tripped the shutter accidentally before moving the camera and a guess the lens zoomed during the exposure (1/4 sec.). This is looking downstream at McCormick's Creek, flowing with a fair volume of water but whose rocky stream bed is mostly covered in snow with lots of ice at the edges. Here's the straight shot of this scene — in full color.

The other direction from this spot is the largest waterfall in the park, aptly named McCormick's Creek Falls, nicely framed in ice. This is a small canyon with a large ledge consisting of two limestone formations being eroded by the creek. Water always seeps through the limestone freezing into great, beautiful icicles in cold weather. 
McCormick's Creek FallsMcCormick's Creek State Park, Owen County, Indiana Beech Leaves in WinterA few leaves hanging on beech trees despite cold and snow. The original color photograph was converted to black&white, except for the few warmly colored leaves in the corner. Among the bare trees, nicely outlined with powdery snow, a few leaves are still hanging on. These are beeches, many of which cling onto some of their leaves until the new ones start appearing in spring and providing some color in the mostly monochromatic winter. There was more color originally in this photo but I desaturated it except for the group of leaves at the top. They leapt out at me at the time but were somewhat lost amid the warm color of the tree trunks but are emphasized even better in this rendering.

Here's a crop of the original. Yes, the leaves are out of focus, I guess they are closer than most of the other trees.

Motion of PlutoA composite of two exposures showing the motion of the dwarf planet Pluto between October 2 and November 11, 2020 against the background stars. Much of this motion is a. reflection of Earth's orbit around the Sun, causing Pluto to appear to shift against the fixed stars.

Whatever you call it, it's mighty far away and relatively tiny; much smaller than any of the "real" planets, even smaller than our own Moon. I had no hope of seeing anything more than a dot of course, even the mighty Hubble Space Telescope* can barely resolve any surface detail.

I did manage to take photographs of the proper area of the sky on a few different nights. The top image shows a composite of the two exposures with Pluto's location marked. There was not much chance of confirming it in one frame because the spot of light is tiny and indistinguishable from similarly faint stars, and I wasn't sure of the accuracy of the position in star catalogs. But by waiting and taking another image it was possible to confirm that what I thought was the correct small dot was where it was supposed to be and had in fact moved as expected. This is exactly how Pluto was discovered in 1930 by Clyde Tombaugh, but I had the advantage of knowing where to look, thanks to trusty SkySafari sky simulator software. The curvy line added to the image above shows the path of Pluto across the sky over time. Much of this motion is actually a reflection of Earth's orbit around the Sun, causing Pluto to appear to shift against the fixed stars due to parallax. Pluto does orbit the Sun as well of course, which contributes to its apparent movement, but it travels much slower due to its tremendous distance. The hugely bright object at the top is the planet Jupiter, which doesn't normally appear that bright but is way overexposed in this deep exposure. 

Pluto's MotionTwo exposures showing the motion of the dwarf planet Pluto between October 2 and November 11, 2020 against the background stars. Much of this motion is a. reflection of Earth's orbit around the Sun, causing Pluto to appear to shift against the fixed stars.

Here's another view of the same data: the two separate images, showing the same area of the sky with Pluto's location on the two dates. It's rendered in reverse, astronomers often show images this way because it's usually easier to see fainter objects, which appear darker in the negative. (Also, astronomical photographs used to be made using photographic film and plates, which produce a negative, and it was best to study and analyze the original rather than a positive reproduction, which might introduce distortions or artifacts.) By November Jupiter had joined the fun and I thought the glare would drown out much fainter Pluto. But it was still brighter than the sky background.

I was able to confirm the identity of Pluto not only by its position, but also the expected brightness compared to adjacent stars of similar brightness. The numbers are magnitudes, the units astronomers use for brightness or luminosity, larger values are fainter, somewhat non-intuitively. At each position I found stars that bracket Pluto's brightness. Also shown on the November image is Pluto's location on the October date, showing how far it had shifted.

*Speaking of Hubble and Pluto, a recent Hubble/STScI news release reports on a study to measure the extremely faint glow of light from the distant universe. They used data from the New Horizons Spacecraft that flew by Pluto and the even more distant object Arrokoth in the Kuiper Belt to get beyond the light reflected from dust in the inner Solar System. Though very faint, this relatively local reflected light can be seen even from the ground in very dark skies and is known as zodiacal light (because it is seen along the Zodiac, the swath of the sky in which the planets travel.). I have managed to photograph the zodiacal light on only two occasions, once in Arizona at Canyon de Chelly National Monument, and on Assateague Island on the Atlantic coast of Maryland.  

There was a lot not to like about 2020, but certainly one bright spot was the appearance of Comet NEOWISE, the best comet in decades and the most exciting astronomical event of the year. 

Comets are not really that rare, but mostly they are are very distant and dim, only accessible to those blessed with very dark, clear skies and powerful telescopes. Every once in a while one will be predicted to get brighter because of its intrinsic size and an orbit taking them close to the Sun and the Earth. But they're also fickle, predictions often fail to come to pass because we can't really study the small, icy cores in enough detail except with space missions to travel up close, and those are even rarer because of the difficulty and expense. A couple of comets got our hopes up earlier in the year, predicted to brighten to naked-eye visibility, but fizzled. One comet finally beat the odds though and put on a great show for about a month in summer for anyone willing to make a bit of effort, formally known as Comet C/2020 F3 (NEOWISE). (The conventional nomenclature is adopted by the International Astronomical Union to have an agreed-upon way of referring to objects in the sky. The more informal name (NEOWISE) is from the observer or institution credited with the first observation, in this case a NASA astronomy spacecraft.) 

My first view of the comet was from outside the house when the comet was rising just before the Sun in early July, but it already had a prominent tail and bright coma (the envelope of gas around the small, solid nucleus).

Comet NEOWISE before sunrise July 5, 2020Comet C/2020 F3 (NEOWISE) before sunrise, July 5, 2020.

A couple of days later I ventured to a location with a clearer eastern horizon to watch the comet rising through clouds above Monroe Lake, not far from home. Already the comet appeared brighter with a more prominent tail, though some of that was due to the better contrast against a darker sky since I could catch it lower on the horizon. 

Comet NEOWISE over Lake MonroeComet C/2020 F3 (NEOWISE) over Lake Monroe, Indiana this morning. The comet was just 6½º above the horizon about an hour before sunrise.
Nikon D850, 80-200mm f/2.8 @80mm, 6 sec., f7.1, ISO 1600, iOptron CEM75p tracking mount.

Comets do present a challenge to photograph well, even one as prominent as NEOWISE. There have been brighter ones, visible in daylight, but this wasn't one of those. Most of the time they are small in angular size so you need a long focal length lens, or choose to have a wider view with the comet in the context of a foreground landscape. Also, despite how they appear in photos, they are still pretty faint so you need deep exposures: long exposure times and wide apertures with fast lenses. The photo of the comet above Lake Monroe was taken at 80mm, 6 seconds, f/7.1, ISO 1600. The camera was mounted on a telescope drive to compensate for the motion of the sky due to the Earth's rotation.

We were fortunate to have clear skies for several mornings while the comet grew in brightness as its orbit took it closer to the Sun. Watching it was exciting, but a challenge to get up early enough, well before the early mid-summer sunrise to venture out to a suitable location, set up equipment and frantically photograph for an hour or so, then turn around and do it all over again for a few days in a row. 

Comet C/2020 F3 (NEOWISE)I think this is the best I can do with this comet so far. I got up crazy early again this morning and headed back out to Brown County to watch it rise, probably the last time, hoping to get some deep exposures before the sky got too bright. (I will still be chasing it after sunset as long as the weather cooperates and the comet is still visible.) I was at an overlook on a ridge with a very clear northeast horizon and very little clouds or haze and the sky was very clear for an Indiana July.

I shot a sequence of 21 images tracking on the stars with a Nikon D850 DSLR and 200-500mm f/5.6 lens at 300mm mounted on an iOptron CEM25P telescope drive. Each exposure was 45 sec., f/7.1, ISO 2000. I did a fair amount of post-processing (that I hope to describe in more detail separately).

The result shows a lot of interesting features. There are two tails, common in bright comets: the bright, curved dust tail of particles shed by the comet and the fainter, straight, bluish gas/ion tail, pushed back by the Sun's magnetic field and wind (comet experts please correct any misstatements). I see some additional structure, particularly in the dust tail. There's also some structure in the coma, the brighter area around the nucleus.

I registered the individual frames on the comet so the stars are trailed because the comet is moving through the solar system so does not track with the stars. Also the sky background varies because the comet was low on the horizon with some light pollution and early beginnings of dawn. I tried to suppress much of that gradient and even out the background to bring out as much detail as possible in the comet.

Now the comet began to swing around the Sun and couldn't be seen in the glare, but it soon emerged on the other side, visible in the evening after sunset, and still brightening as it came closer to the Earth. It was a little easier on the schedule, not having to wake up in the dark pre-dawn. This was the time during which I got the most detailed images, now sporting two tails. One tail is made mostly of small dust particles, reflecting sunlight and trailing along the comet's curving path, the other is mostly ionized (electrically charged) gas, blown back in a straighter line by the charged particles in the solar "wind", and with a distinctly bluer color. Also the coma, the glowing material around the unrresolved nucleus now showed a clear green color. At this time the comet was close enough that I could use a wider-angle lens, in this case zoomed out to 200mm to more than fill the frame with the long tails.

Comet C/2020 F3 (NEOWISE)

The comet was now in a darker sky which provided more contrast, making the faint tail visible quite far away from the nucleus. But this also required deeper exposures to capture the faint details, in this case: 20 seconds, f/3.5, ISO 6400. The longer exposure times made it much more important to use a tracking mount to follow the motion across the sky. 

As the comet continued on its journey back out to the far reaches of the Solar System, it faded but still provided some interesting views. I caught it in the west after sunset over Strahl Lake in Brown County State Park, and happened to also catch a meteor in one of the frames.

Meteor Photobombs NEOWISEA meteor streaks by Comet C/2020 F3 (NEOWISE) over Strahl Lake in Brown County State Park, Indiana. A composite of 30 frames processed in Lightroom and combined in Starry Landscape Stacker.

But that wasn't the only interloper. I tried to take as many exposures as possible in each session, combining them later in software to improve the dynamic range and reduce the noise in the final images. In many of these fairly long exposures, usually 30 seconds or so, satellites trailed across the field. Brightest was the International Space Station, crossing right through the tail of the comet (not actually the tail of course, the ISS is in a low orbit around the Earth while the Comet was millions of miles away). 

ISS Photobombs Comet NEOWISEHow's this for serendipity? The International Space Station (ISS) photobombs Comet NEOWISE. I didn't even see this last night but noticed it while post-processing a series of comet images and confirmed with SkySafari.
Nikon D850, 80-200mm @120mm f/2.8, two frames 30 sec. each, f/3.5, ISO 6400. The gap in the ISS trail is because the frames were separated by about a second.
#NEOWISE, #ISS

In another case, several of the new Starlink satellites passed through the field in a few frames, leaving parallel trails like a music staff. This photo is a composite of those frames and also includes another, brighter satellite.

Fortunately, these sorts of trails disappear when combining multiple exposures. But more and more satellites are planned to be launched, thousands in the Starlink program alone, so will become a nuisance not only for making photographs like this, but for observations used for scientific research, though it's not clear how to balance the desire for faster, higher-bandwidth communication and other earth-bound uses with the needs of science.

Finally, by early August the comet was no longer easily visible, even in binoculars. But I managed to capture one more view, with a long lens and deep exposures. There is only a hint of the formerly glorious tail and a relatively bright, green coma. (The color is due to carbon compounds energized by sunlight and producing light.)

In this photo several separate exposures (each 60 seconds, f/7.1, ISO 4000) have been combined, centered on the comet. The stars are trailed because the comet is moving relative to the stars; partly because of the motion on its orbit, but also partly because our point of view is changing as the Earth moves along its orbit (the apparent displacement is known as parallax).

It was an incredible experience to follow and photograph such a spectacular sky phenomenon, and I was very grateful that I could spend the time to take advantage of it and get some once-in-a-lifetime photographs, though it taxed my sleep schedule. It was also a pleasure to be able to spend time with some like-minded folks — safely distanced — on several occasions to do some serious photography.

Here's one parting shot, a panorama of the full arch of the summer Milky Way with the Comet NEOWISE at the left edge. This was made at one of the darker locations in southern Indiana, near the small town of Williams, which also is home to a very attractive covered bridge that appears on the far right of the photo.

Jupiter/Saturn Conjunction December 21, 2020The conjunction of Jupiter and Saturn seen on December 21, 2020 from Monroe Lake, Monroe County, Indiana.

If you're interested to delve more deeply into this, including a perspective from the Hubble Space Telescope, check out the Illuminated Universe blog post.

I was also able to get some photos with a small telescope, good enough to show some detail in in the planets' disks and several of the moons of each but with both planets in the narrow field of view. This is not as simple as it sounds. Even though these planets are enormous — Jupiter is the largest in our Solar System — they are also immensely far away so they appear tiny, even with high magnification. Also, though the planets themselves are fairly bright, reflecting a healthy amount of sunlight, their moons are much smaller so appear as much fainter stars from our vantage point. I took photographs with different exposure times to capture this wide range of brightness and was able to composite together a reasonable view.

Jupiter/Saturn Conjunction December 20, 2020The great planetary conjunction, December 20, 2020, a day before closest approach. this is a composite of different exposures for the planets and the moons, Jupiter below and Saturn above. No, Jupiter didn't suddenly grow a fifth bright moon, that's a star (HD 191250) photobombing. Three of Saturn's brightest moons are visible in the first photo, but more are visible in the second longer exposure which also IDs them, along with some background stars.
Tech: Nikon D850, Celestron C5 (1250mm f/10), the left photo is a composite of 1/10 sec., ISO 200 and 1.3 sec., ISO 800; the right photo is a composite of 10 frames, 10 sec, ISO 1600, processed in Lightroom, registered and median-combined in Photoshop.

Here's one of the longer exposures. The planets are overexposed, but the moons are very clear, along with a few background stars. It was a little surprising to see what appeared to be a fifth bright moon of Jupiter, but it turned out to be a star that just happened to be in line with the actual four bright moons, known as the Galilean satellites, named for Galileo who was the first human to see them, through his telescope.

The next night was the actual closest approach and lo and behold it was clear again! Unfortunately it was also rather windy, which caused the camera and telescope to jiggle, making the images a little blurry (poor "seeing" in astronomer-speak). But again I was able to take photos and blend them together to show the planets, moons, and stars, all in a different configuration; Saturn had slid along relative to Jupiter, they both had shifted relative to the stars, and the moons had moved around their orbits.

Jupiter/Saturn Conjunction December 21, 2020The conjunction of the planets Jupiter and Saturn on December 21, 2020, the winter solstice. It shows all four Galilean moons of Jupiter, the two brightest moons of Saturn, and three background stars, all labeled in the second photo.
This photo is a composite of several frames at different exposures to capture the planets and the moons. It was pretty windy though so the camera was being moved around enough that the photos aren't quite as sharp as they could be, but there is a bit of detail in the planets.
Tech: Nikon D850, Celestron C5 (1250mm, f/10), iOptron CEM25P drive; exposures: 1/25 sec., ISO 320, 1 sec., ISO 1250, 2 sec., ISO 3200.

The next day turned out to be clear again and I ventured out once more to catch the continuing slow-motion dance of the planets. This time the weather was more cooperative and the seeing was much better so more detail is visible on the planets.
Jupiter/Saturn Conjunction December 22, 2020The Great Conjunction, still close in the sky. The conditions were much better this night, no wind and better seeing (jostling of the air) so I got some sharper images of the planets, likely the best I can do with the equipment at hand.
This is a composite of several frames with different exposures, combined to show the brighter planets and fainter moons well, along with a couple of background stars.
Tech: Nikon D850, Celestron C5 (1,250mm f/10), iOptron CEM25P drive. Multiple frames with three exposure times: 1/25 sec., ISO 250, 4 sec., ISO 4000, 8 sec., ISO 6400, processed in Lightroom, stacked in Photoshop (registered and median-combined).

Note also the relative position of the moons have changed, we can again see all four of Jupiter's Galilean moons and the three brightest moons of Saturn. These moons complete orbits in a few days, so it doesn't take long for them to be in very different positions, maybe a little easier to see in this view of all three nights.
Jupiter/Saturn Conjunction December 21-22, 2020The Great Solstice Conjunction of Jupiter and Saturn, December 20-22, 2020
These images are all composites of multiple varying exposures: shorter times to avoid overexposing the planets and longer times to capture the much fainter moons and background stars. In addition, I made numerous repeated frames at each exposure that were combined in order to reduce noise in the final image. While post-processing I was very surprised to see the trail of an aircraft passing right in front of Jupiter in one of the close-up frames through the telescope. It's very common to see aircraft lights trailed in long exposures in wider views of the sky at night, but much rarer to capture one in such a small field.

But that's not all. As long as I had the equipment set up, I thought I'd explore some of the other inhabitants of the outer Solar System that happened to be above the horizon at this time. These are much smaller and some more distant than the giants Jupiter and Saturn, but I thought it would be fun to make a gallery of sorts of these far-flung inhabitants of our corner of the universe.

First up is Uranus, centered in the photo in a field of stars. It's next in orbit beyond Saturn, known as an ice giant planet because of its composition and size. Uranus is bright enough to possibly be seen by someone with excellent vision in a very dark, clear sky but not by me. And it's not resolved here into anything more than a brightish star because it's smaller and much farther away than Saturn. But we can make out two of its brightest moons Oberon and Titania. Yes, Uranus's moons are named after Characters in plays by William Shakespeare.
Planet UranusThe Planet Uranus, an ice giant between Saturn and Neptune and its brightest moons Oberon and Titania. (Yes, the moons of Neptune are named after Shakespeare characters.)

Next, beyond Uranus is Neptune, the farthest full-fledged planet, along with its brightest moon Triton. Also just a point of light, not visible without a telescope but bright enough to photograph.  

Planet NeptuneThe planet Neptune and its largest moon Triton, Deep in the Solar System between the orbits of Uranus and Pluto.

Finally there's Ceres, now classified as a dwarf planet, the first discovered and largest object in the asteroid belt between Mars and Jupiter. One of five dwarf planets now known, it's smaller than Pluto and smaller than Earth's Moon. Not a spectacular photograph perhaps, but it is interesting to be able to image such a small body add to the gallery of these relatively faint targets in the far reaches of the Solar System.

Dwarf Planet CeresCeres, the largest object in the asteroid belt between Mars and Jupiter, it is large enough to now be classified with Pluto as a dwarf planet.
A composite of multiple exposures, Nikon D850, Celestron C5 (1250mm f/10), 20 sec, ISO 6400, processed in Lightroom, stacked in Starry Sky Stacker.

Oh and just one more: our nearest neighboring rock, the Moon of course, which rewards with a whole lot of detail. 

Because of the pandemic, I missed some travel that I had been eagerly anticipating, but still was able to have some new adventures and explore some areas of photography more deeply. Here are some of my favorite photos from the past year.

Barred Owl   Whooping Crane in Flight
Early in January I went to west-central Indiana with some other photographers where a lot of interesting birds often hang out. Driving slowly along one of the back roads a car-mate suddenly said, "Stop the car!" We followed his gaze and saw a fine barred owl calmly surveying his territory from a perch not too far away. We quietly and carefully got out of the car and were able to take numerous frames before the bird flew off. It would have been nice if there weren't so many branches in the way, but I managed to get some pretty nice shots of this handsome bird looking back at us. A little later we stopped at a location where sandhill cranes often hang out. But instead of sandhills we saw a couple of magnificent whooping cranes, much rarer but often found traveling with their crane cousins. The whoopers took off and flew right above us so close it was difficult to track and frame them with a long telephoto lens. But I did manage a couple of frames of a magnificent bird with outstretched wings. (If you look closely you can see a tracking device on one of its legs. These birds are so rare that many of them are tagged and tracked by wildlife experts working to increase their numbers.) I am fortunate to have become acquainted with a number of local folks who are experienced bird photographers and familiar with locations such as this. I'm not as accomplished at this particular type of photography, but learning a lot and certainly grateful for the guidance of these folks.

Oaxaca Wedding Band  
Later in January my wife and I were privileged to travel to Mexico to attend the wedding of one of our nieces to a young man from the small town of Teotitlán in the state of Oaxaca. This was not a resort wedding, but a traditional affair following many long-time customs of the local culture there. What a great experience to be welcomed into the home of the groom's family and take part in the festivities, including traditional dancing, much cerveza, mescal, and terrific food. I had to admire the wedding band: not only did they march and play to lead a parade from the home to the church - and back, but they played for many hours during three days of celebrations.

We also were able to spend a little time touring the area, including a couple of ancient archeological sites of the ancient Zapotec culture that thrived in the area a thousand years ago. Many monumental stone structures remain, with amazing designs that are still used in local crafts. (More examples are in a previous blog post.)

Mitla Walls Drying Yarn
Teotitlán is known for the high-quality weavings traditionally made on large manual looms from locally sourced and dyed wool. In fact the operators of the bed & breakfast where we stayed were also weavers and we were able to see parts of the process, including dying and weaving.  It was certainly a highlight of the year, and we were grateful for this last opportunity before the pandemic prevented travel.

Comet C/2020 F3 (NEOWISE)   Comet NEOWISEA wide-ish view of Comet NEOWISE photo from a convenient overlook in Brown County State Park, Indiana after sunset. Earlier clouds graciously dissipated in time to get a nice view. The comet is getting brighter, very clearly visible naked eye, and the two tails are quite clear in the photo. This exposure shows more brightness in the sky than was visible.
Nikon D850, Rokinon 85mm f/1.4; 30 still frames, 4 sec. f/4, ISO 6400, post-processed in Lightroom, combined in Starry Landscape Stacker.
One of the most exciting events in 2020 was the unexpected arrival of an amazing comet, the brightest one in many years, known as Comet C/2020 F3 (NEOWISE). It came at a great time, as I have been ramping up my astrophotography equipment and experience (and something I could do while adhering to social distancing guidelines). But the schedule and the anxiety over clear skies were brutal! At first the comet was visible only in the early morning before sunrise, so several times I got up in the middle of the night, traveled to locations with a low eastern horizon, set up equipment, and frantically photographed until it got too light to see the comet. Later the schedule was a bit more civilized with the comet visible in the west after sunset. But the drill was the same: travel to a location with a good western horizon, set up equipment and shoot until the comet set. But the effort was worth it, with many nice photos of a rare and beautiful astronomical event.

North America NebulaThe North America Nebula (NGC 7000), a star-forming nebula in the constellation Cygnus. A composite of 19 frames, 90 sec. each, f/8, ISO 6400, Nikon D800 modified to record the light of hydrogen. Processed in Lightroom and combined in Starry Sky Stacker.
In line with the comet experience, I have been more interested in pursuing astronomy subjects. Of course I have been immersed in astronomy imaging for most of my career. But after retirement I wanted to go in a slightly different direction from the more technical development of images for the Hubble Space Telescope mission and follow some of my original interests in astronomy, views of the sky and details accessible with more modest telescopes and equipment. One of the challenges in this type of photography is finding locations that are away from city lights and waiting for clear weather, all of which requires patience, planning and time. But it also helps to have like-minded folks similarly interested, especially those more familiar with the area than this relative newcomer. Though I continue to struggle with a few equipment challenges, I have managed to start to get some results that are satisfying. One of my favorites so far is the North America Nebula (named for its resemblance to the geography). An earlier blog post describes a previous version of this image that happened to be photobombed by a bright meteor.

I hope to continue this process, keep on learning and improving, and hope to have more images to show in the coming year.

Barred OwlBarred Owl in Gibson County, Indiana Whooping Crane in Flight Mitla Walls Drying Yarn Paynetown Sunrise Milky Way over Williams Bridge Lightning StormA composite of 7 frames, exposed using a Pluto Trigger. Comet C/2020 F3 (NEOWISE) Morning Glory Detail Cosmos Red PepperWith apologies to Edward Weston. North America NebulaThe North America Nebula (NGC 7000), a star-forming nebula in the constellation Cygnus. A composite of 19 frames, 90 sec. each, f/8, ISO 6400, Nikon D800 modified to record the light of hydrogen. Processed in Lightroom and combined in Starry Sky Stacker. Coming in for a Landing

Sunspots are immense magnetic storms in the upper layers of the Sun, often covering an area larger than the Earth. They're dark because they are cooler than the surrounding area and produce less light — though still tremendously hot, about 6,400ºF compared to 10,000ºF for the visible surface. Also notice the brighter areas around the sunspots, most noticeable when the spots are near the edge of the sun. These are also associated with the magnetic disturbance and are called faculae.

There was enough clear weather in early November to photograph the Sun on 11 consecutive days around the same time each day. On some days there were passing clouds but there was always enough clear sky to get a photo. I tried to get photos at the same time, around midday as much as possible so the times would be spaced evenly. The photo at the top is a composite of the frames showing the group of spots crossing the Sun and changing shape. Sunspots stay pretty much in the same place on the Sun but appear to move across the disk because the Sun is rotating, taking about 25 days to complete one rotation (though since there's no solid surface, the rate of rotation is different at various latitudes). They do move somewhat in latitude (toward or away from the poles) over time though.

Here's a time-lapse video from the same still frames showing the spot crossing. The inset detail shows a large view of the spots as they change and fade toward the end. Some of the changing shape is because we see the surface tilted away from us causing features to be distorted by the foreshortening. But the spots do change as the storm develops and then subsides.

The Sun consists entirely of gas and plasma (ionized gas) at extremely high temperatures and incorporates extremely strong magnetic fields with very complex dynamics. Sometimes the magnetic fields get twisted and produce spectacular events and solar storms, including ejecting vast streams of energetic, electrically charged particles into the Solar System. If these streams hit the Earth they can cause brighter than usual aurora (northern and southern lights) and if strong enough can disrupt electronic communication and can even disable electrical grids and orbiting satellites. These events are more common during times of greater sunspot activity during the 11 year sunspot cycle. 

These photos were made with a Nikon D850 DSLR and Celestron C5 telescope (1250mm focal length, f/10) with a Baader solar filter, mounted on an iOptron CEM25P drive to follow the motion of the sun across the sky. Exposures varied somewhat because of changing conditions, passing clouds, etc., but were approximately 1/5000 sec., ISO 160 (the telescope has a fixed f/10 aperture). I shot numerous photos on each day in order to capture at least some frames that were as clear as possible. The Earth's atmosphere is very dynamic and distorts and blurs the light from the Sun and stars on very short timescales (which we experience as the stars twinkling), especially during the day as the Sun unevenly warms pockets of air. Using a fast shutter speed and taking many frames can help increase the chance of capturing a particularly clear moment.

As an example, these two frames were taken just a second apart, the one on the right is noticeably clearer, revealing some interesting details in the central structures.

Photographic plate of asteroid 7 IrisPhotographic plate of asteroid 7 Iris, September, 1973 taken with the Indiana University Kirkwood Observatory 12-inch telescope.

Asteroid 7 Iris, September 28, 1973Asteroid 7 Iris, September 28, 1973 on a glass plate taken with the Indiana University Kirkwood Observatory 12-inch telescope for an astronomy class assignment. Kodak IIaO plate, exposure unrecorded.

For some reason I got it in my head to see if I could photograph the same asteroid with my camera. This is a relatively bright object so I figured it would't be too hard. In fact it's the fourth brightest of all the asteroids and was the 7th asteroid discovered, back in 1847, hence the formal designation 7 Iris. It's now known to be in the Main Belt of asteroids, between the orbits of Mars and Jupiter. It's a rock only about 200 km (120 mi) in diameter 150 million miles away with an unusually bright surface and even has surface features identified from very detailed observations by the European Southern Observatory's Very Large Telescope. But it's too faint to see naked eye so needs long exposures or a large telescope. I don't have a large telescope but I can make reasonably deep exposures with a very sensitive digital camera and fast telephoto lens. And while a single clear, dark night isn't too unusual around here, I wanted to confirm that I was getting the asteroid, which changes position night to night. So I wanted at least two images separated by some time to show its motion, which needed some extra effort. Asteroid 7 Iris, October 2020Two photos of asteroid 7 Iris, Oct. 7 and 16, 2020. Nikon D850, 200-500mm f/5.6 lens @ 500mm, 60 sec., f/7.1, ISO 3200, iOptron CEM25P drive. This is a mosaic of two photographs taken nine days apart with Iris identified as it moves across the Milky Way. Its brightness is intermediate between the brightest stars in the frame and many much fainter stars in the field at about magnitude 10.5 on astronomers' brightness scale. There are also a couple of star clusters nearby: Messier 25 (M25) is the large cluster near the top center and the smaller Trumpler 33 is at right. These are physical associations of stars in the Milky Way Galaxy called open clusters, known to have formed at about the same time at least a few million years ago.

I'm not ambitious enough to do something like calculate Iris's orbit, but these are the sorts of observations needed to do that. Repeated observations over many months and years provide data to compute the orbit through the Solar System. 

Back to that old glass plate from college: I hadn't recorded the date it was taken and I couldn't remember exactly when I took the class but thought I might be able to figure that out from the asteroid's position in the sky. I sent the scan of the plate to the amazing facility astrometry.net, software that compares any image of the sky with very accurate star catalogs and returns the position, something I can't imagine doing manually. From the sky coordinates returned by astrometry.net, I was able to find the same location in the desktop sky simulation software SkySafari, which also shows the location of Solar System objects, including asteroids, for any time, past, present, or future. By running the clock back to the early 1970s, I found the date when Iris was within the field of the old plate: September 27, 1973.

Red PepperWith apologies to Edward Weston.

One of the vendors at our local farmers' market has the greatest peppers, especially the sweet red ones. They're large and meaty and very tasty. And they came in a wonderful variety of shapes. They reminded me of the famous pepper photo by Edward Weston, one of the most recognizable images from early 20th century photography. That photo in turn is reminiscent of Weston's figure studies for which he was well known; the forms of the pepper echoing the posed nudes.

So I had to set up an impromptu still-life studio to photograph one of the peppers we brought home that reminded me of a figure in a crouching pose. I sat the pepper on a plain gray background in the north-facing screen porch in daylight, with no other lighting. It's a fairly straightforward photo with a DSLR (Nikon D850) and macro lens (Nikon 105mm f/2.8 Micro), but converted to black&white in Lightroom. I did use a polarizing filter on the lens to try and tone down some of the reflections from the pepper's very shiny skin. Also, because the pepper is large compared to the size of the frame, I knew it could not all be sharply focused in a single exposure. So I took a series of photos focused at different depths within the scene and combined them using Photoshop's Auto Blend Layers tool that combines a set of images using the sharpest portion of each.

For reference, you can see Weston's pepper photo at the Museum of Modern Art's website.
 

Neptune is the outermost of the large planets in the Solar System. (Pluto is now formally known as a dwarf planet, one of the many such objects in the outer Solar System's Kuiper Belt.) Neptune is bright enough that it's clearly visible in photos with moderate exposure. In the photo above it's a medium brightness green star near the bottom-center. When I looked more closely at the image, I also saw another, much fainter dot to the lower right of Neptune. Looking in my trusty sky simulation software (SkySafari) it turns out to be Triton, Neptune's largest moon, about 20% of Earth's diameter, smaller than our Moon. This is a composite of seven exposures with a Nikon D850 and 200-500mm f/2.8 lens at 500mm, each exposure was 2 minutes at f/8, ISO 2000. They were processed in Lightroom and combined in Starry Sky Stacker.

Not only that, but I noticed some fuzzy patches toward the upper right in the image. These are distant galaxies, identified in star charts as NGC 7576, 7585, and 7592 (from the New General Catalog of Nebulae and Clusters of Stars, originally compiled in the 19th C. and revised up to the present). They are 150-350 million light-years away. 
Finally, looking a the separate exposures, there were a lot of satellite trails in a couple of frames. Most of these are from the new Starlink constellation of satellites being launched by SpaceX to provide global broad-band internet. They are the parallel streaks at the bottom of this composite photo, produced by several separate satellites orbiting fairly close together. There's also another unrelated satellite at upper right.

This photo is also a composite of the same exposures making up the previous photo. It was combined in Photoshop in a way to preserve the brightest value in each frame rather than the first photo, which was combined in a way to average out the brightness between the frames to make a clearer image. There are so many of these satellites that their trails show up in a surprisingly large number of photos of the night sky. And more are being launched all the time, so we're in for an interesting time in astronomy. Fortunately for the kind of astrophotography that I have been doing, the trails disappear when multiple exposures are combined, as with this example.

Fireflies in the Garden 
by Robert Frost

Here come real stars to fill the upper skies,
And here on earth come emulating flies,
That though they never equal stars in size,
(And they were never really stars at heart)
Achieve at times a very star-like start.
Only, of course, they can't sustain the part.

https://www.poetryfoundation.org/poems/42892/fireflies-in-the-garden

I can't think of more appropriate words to describe the experience of watching fireflies on a clear, early summer night. As we transition to autumn now, reading these words is a welcome reminder of warm summer nights watching fireflies and photographing the night sky. Here are a couple of photos that attempt to capture what I've seen a few times and echo Robert Frost's words. Fireflies gather in great numbers around meadows and forest edges, their flashes of light sending coded messages to potential mates. It's hard to capture this in a single photo, which may record a few short flashes. But blending numerous images together adds multiple flashes on top of one another, making for a more dramatic result.

The first photo is a composite of about 60 frames of 15 seconds each with a 20mm lens, taken in Yellowwood State Forest in Brown County, Indiana. In all but one frame the sky was removed with a mask to keep the motion of the sky from streaking out the stars and Milky Way. The images of the foreground then blended together to show the very many flashes of the fireflies. You may also notice a meteor from one of the sky frames at upper right, almost lost compared to the much brighter nearby fireflies.

The second photo combines 50 frames, 15 seconds each, spanning a total time of about a half hour in rural Greene County, Indiana, also taken with a wide-angle 20mm lens so we see a wide area of sky. The stars are streaked because the camera was stationary. It's interesting to see how their large numbers of fireflies seem to make the trees glow as they gather around the edges. 

Veil NebulaThe Veil Nebula, aka Cygnus Loop, the remnant of a long ago supernova explosion. A composite of 22 frames 90 sec. each, f/7.1, ISO 6400, Nikon D800, modified for sensitivity to hydrogen light, tracked with an iOptron CEM25P mount. Processed in Lightroom and combined in Starry Sky Stacker.

One of the objects I was able to photograph not long ago is the Cygnus Loop (also known as the Veil Nebula), the remnants of a star in our Milky Way Galaxy that blew itself apart in a titanic supernova explosion a long time ago. One of the reasons I wanted to make this picture was some connections I have with this target. For one, I helped produce one of the Hubble images of this object. It's just a teeny-tiny part of the enormous region, but reveals the exquisite structure at all its physical scales.

Veil Nebula from the Hubble Space Telescopehttps://hubblesite.org/contents/media/images/2015/29/3620-Image.html

Another reason I pursued this goes back exactly 50 years to my first college astronomy class in the Fall of 1970. The textbook we used was Exploration of the Universe by George Abell and on the cover was a picture not too different from mine, a zoom-in showing only one section of the full area, the left region of nebulosity but in greater detail. And yes, I still have the book, one of the best textbooks I had and one I've referred to many times over the years. Also note the vintage punch cards used as bookmarks — originally, input to the CDC 6600 mainframe computer I used in college. I think that might be a line of COBOL! 

I don't know all the details of that cover image, the caption only refers to the source as Mt. Wilson and Palomar Observatories. I'd guess it was made in the 1960s, certainly from monochrome glass plates, likely using the 48-inch Schmidt telescope on Mt. Palomar. It may have been assembled from images used to produce the comprehensive all-sky survey known as the Palomar Observatory Sky Survey (POSS). These are wide-field (about 6º square) photographs originally taken in two colors covering the whole sky as seen from Southern California.  The color image from Palomar would have been made painstakingly in the darkroom by combining copies of the plates taken through different filters, rather unusual at the time before much more convenient digital photography. Looks like the last edition of the textbook was in 1995, and sports a great photo of the Hubble Space Telescope on the cover. 

The POSS was revolutionary in astronomy and used extensively, not only as a guide to more detailed observations but as a research tool in itself. In fact one of George Abell's greatest accomplishments (besides writing one of the most-used astronomy textbooks) was the systematic cataloguing of clusters of galaxies using the POSS plates. But even beyond that, the POSS was digitally scanned and used to compile a catalog containing millions of stars with very precisely measured positions and brightnesses used to very accurately point the Hubble Space Telescope: the Digitized Sky Survey and Guide Star Catalog. Subsequently, later generations of plates were taken with improved technology and additional filters to extend and refine the images and catalogs derived from them.

Now I can turn my off-the-shelf — albeit high-end — thoroughly modern digital SLR camera to the same spot in the sky and make what I consider a respectable photograph of the same subject. Sure it's not the equal of an image made by a gigantic telescope on huge pieces of sensitized glass (or even by more sophisticated backyard astrophotographers) but I think it's a beauty: filled with stars and showing colors of ionized gases in clouds energized by the long-ago explosion of a dying star. So I feel I've come full-circle in some respect, with a few twists and turns along the way — the (sort of) circular Cygnus Loop is something of a metaphor for me then: a beautiful celestial object now bringing to mind many aspects of my life.

Seeing or photographing the planet Mercury is a challenge, as it orbits so close to the Sun. But when the geometry is right, it's visible just before sunrise or just after sunset as a star in the fading sky glow. The other day I was using the trusty SkySafari sky chart software to check the phase of the Moon. I knew it was a thin crescent just after new phase and it would be setting shortly after the sun. But I also noticed that Mercury would be relatively nearby in the sky. And as luck would have it, the sky was crystal clear, after days of thick haze from western wildfires were cleared out by clearer weather from the north. I found a location with a low western horizon at a nearby wildlife preserve, Stillwater Marsh in Brown County, Indiana. 

Just after sunset I searched and found the Moon and set up the camera on a tracker so it would stay fixed in the view and selected a lens that should put both the Moon and Mercury in the frame. As the sky got darker I kept shooting but never did see Mercury naked eye or on the camera's preview screen. But when I unloaded the images and began processing them, sure enough it showed up, though just barely. Wasn't even sure it wasn't a hot pixel (flaw in the camera sensor) but it appeared in the right place in several frames.

In case you can't see it in the picture above, here's an annotated version with an inset of Mercury in the lower left enlarged.

Also, here's a closer look at the crescent Moon from a separate frame with the lens at 500mm. It's hard to get a good, sharp image of anything in the sky near the horizon. We have to look through a lot more of the atmosphere than when we're looking straight up and all that air is dancing around, causing the light from bend around it. (That's why astronomers launch telescopes into space, like  Hubble, to get beyond the distorting atmosphere.)
Crescent MoonCrescent Moon 48 hours after new. Nikon D850, 200-500mm f/5.6 @500mm, 1/250 sec., f/9, ISO 400, tracked with iOptron CEM25P drive.

A Rare SunspotThe Sun is going through a deep sunspot minimum, meaning there are very few if any sunspots visible these days. One sunspot appeared recently and I photographed each day it as it moved across the face for about a week as the Sun rotated. Unfortunately I missed the first couple of days after it appeared. Tech: Nikon Z 6, Celestron C5 telescope (1250mm f/10), eight frames, 1/2000 sec, ISO 100. iOptron CEM25P mount, Baader solar filter. Post-processed in Adobe Lightroom and Photoshop.

Some of that activity is visible as sunspots, darker areas that are cooler than the surrounding visible layer due to complex magnetic activity. Sometimes powerful flares erupt from the surface that blast vast quantities of energy and particles, some of which can reach the Earth and beyond. The most powerful ones can disable orbiting satellites and knock out power grids. We can also see prominences at the limb, fingers and arches of glowing hydrogen plasma sculpted by magnetic forces. Normally we need specialized equipment to view these but during rare total solar eclipses we can see them with naked eyes through small telescopes because the Moon blocks out the brightest part of the Sun. I was able to photograph prominences during the eclipse of 2017. 

Prominences, Total Solar Eclipse August 21, 2017Solar eclipse August 21, 2017, Grand Teton National Park. Nikon D800, 200-500mm f/5.6, @500mm, 1/1000 sec. f/11, ISO 200, on iOptron SkyGuider Pro drive.

The Sun is going through a deep sunspot minimum now though, meaning the overall activity of the sun is low and there are very few if any sunspots visible these days. One sunspot did appear recently though and I was able to photograph it each day it as it moved across the face for about a week. The same sunspot appears on consecutive days as dark dots below the center, superimposed onto a single image. Unfortunately I missed the first couple of days after it appeared, otherwise there would have been another spot on the left side of the sequence. They are not spaced equally because I didn't take them all at the same time of day. The sunspot is actually relatively stationary on the Sun's visible surface, but the whole Sun rotates with a period of about 25 days. Actually since the Sun is entirely gas and plasma, different parts rotate at different speeds, unlike a solid body like the Earth. If there were several spots at different latitudes we would see them move across the Sun at different speeds. 

A Rare SunspotThe Sun is going through a deep sunspot minimum, meaning there are very few if any sunspots visible these days. One sunspot appeared recently and I photographed each day it as it moved across the face for about a week as the Sun rotated. Unfortunately I missed the first couple of days after it appeared. Tech: Nikon Z 6, Celestron C5 telescope (1250mm f/10), eight frames, 1/2000 sec, ISO 100. iOptron CEM25P mount, Baader solar filter. Post-processed in Adobe Lightroom and Photoshop.

Tech: Nikon Z 6, Celestron C5 telescope (1250mm f/10), eight frames, 1/2000 sec, ISO 100. iOptron CEM25P mount, Baader solar filter. Post-processed in Adobe Lightroom and Photoshop.
 

Hubble Space TelescopeThe NASA/ESA Hubble Space Telescope in orbit, photographed by the crew of the Space Shuttle Atlantis on the STS-125 mission to repair and upgrade Hubble.
Credit: NASA and ESA

While the Hubble Telescope has been watching the universe, I have been watching Hubble go by in the sky, or trying to. Hubble is visible in the sky like many other spacecraft. Well, a lot of other spacecraft are much easier to see. The International Space Station is very bright (only the Sun and Moon are brighter sky objects) because it's very big and it passes high overhead frequently because its orbit is highly inclined relative to the Earth's equator. Even though Hubble is large (about the size of a city bus), it's much smaller than the ISS and its orbit is inclined only 20º or so to the equator so is always low in the sky from more northerly latitudes, like the mid-Atlantic. It is so faint that it's really hard to see, but I have been able to capture it in photographs at least.

Visible passes are rare enough that you have to know where and when to look. Fortunately software is available to help. I use an amazing program called SkySafari that is a general-purpose sky simulator, showing the view of the sky from anywhere at any time, including the Solar System, stars, deep sky objects (nebulae, galaxies, etc.) as well as Earth-orbiting satellites. It will predict when spacecraft will be visible and even send notifications when they are rising, which is a great way to catch these relatively rare events.

I have photographed Hubble passes a few times, from three different states as it happens: Maryland, Utah, and Indiana. The first time was in March 2018 when I still lived in Maryland. This photo shows Hubble's path in the glow of lights of suburban Ellicott City, Maryland, along with a number of stars and a few aircraft. The path is interrupted because this is a composite of several 15 second frames with a roughly one second gap between exposures. The path also varies in brightness; the light we see is reflected sunlight, as the angle between us, Hubble, and the Sun changes, different parts of the telescope reflect varying amounts of sunlight.

I also caught a pass of Hubble from Capitol Reef National Park in Utah while I was an artist-in-residence there in June 2018. As before, the photo is a composite of several 15 second exposures with a small gap between them. 

Most recently was shortly after moving to Indiana and not planned out as the other opportunities. I was out shooting at night and got a notification from SkySafari that Hubble was rising. Since I was already set up for night sky photography, I was able to shift around and point to the right part of the sky and just barely caught the faint trail. Even thought the sky was fairly bright from a rising moon, there was a faint trace of the Milky Way as well. I have labeled a few prominent features in this part of the sky. The "M" objects are in a catalog of deep sky objects compiled long ago by the French astronomer Charles Messier. 

These may not be awe-inspiring photographs, but it has been fun and rewarding to chase Hubble and capture even a faint glimpse of this amazing contraption that has allowed us to learn so much more about the universe. I also can't help thinking about the army of talented, dedicated people who conceived, built, serviced, operate, and use the data from this magnificent instrument.

Lyrid Meteor and the North America NebulaThis was taken from Brown County, Indiana on a cold, clear, moonless morning of April 22nd at 3:04am EDT with a Nikon D800 DSLR, converted to record H-alpha, and Rokinon 85mm f/1.4 lens on an iOptron CEM25P mount. It is a composite of six exposures, each 30 sec., f/2.8, ISO 1250, post-processed in Adobe Lightroom and Photoshop. All the frames were registered and median-combined, and the frame with the meteor was added back in Lighten mode.

On this night several circumstances converged, but mostly luck prevailed. This was near the peak of the Lyrid meteor shower in late April. It was clear overnight, pretty rare here in Indiana in the spring, and I was trying out some equipment that I still need to exercise to take full advantage of. I'd hoped to get some views of meteors with a camera and wide-angle lens tracking the "radiant" of the shower (the location in the sky from which the meteor trails appear to radiate) and taking a sequence of time-lapse frames.

In the meantime, I was using another camera to take closer views of some interesting locations in the sky, mounted on a more precise tracking drive. This camera had been modified to capture light from glowing hydrogen that is normally blocked in stock DSLR cameras. Because some of the most interesting places in the sky are full of glowing hydrogen, it's possible to modify the cameras to fully capture these views. One such place is the North America Nebula, also familiar to astronomers as NGC 7000 a region of active star formation. It is one of the larger such areas in the sky and a good target for a moderately long lens, 85mm in this case. 

I was pleased with the results I was seeing at the time, but didn't entirely realize what I'd gotten until I was loading the photos from the memory card onto my computer. Looking more closely, I noticed that not only was there the very bright trail, since I had taken several identical frames (to later combine in post-processing to improve the quality) but in two other frames I could see the trail of the meteor fading and distorted by the upper atmosphere wind, the orange glow between the pink nebula and Deneb.

I haven't had a whole lot of good results from watching and photographing meteors. It can be satisfying to get outside at night and just watch the sky for a while. Despite the internet hype though, meteor showers are not usually spectacular light shows. The frequency of meteors does increase during showers, but most of the time there still may only be a few per hour over the whole sky. Things like city lights and bright moonlight usually interfere and you see the flashes of only the brightest meteors, which are rare indeed. 

Here are a couple of examples of one of the best showers, the Perseids that appear in August every year.  I keep hoping for a spectacular show, which does happen occasionally with this shower, but haven't been rewarded quite yet. 

Perseid Meteors above Sprague LakeI was thinking about how to process some night sky results and revisited some photos from the Persied meteor shower last August. I happened to be in Rocky Mountain National Park, usually a pretty good site for dark and clear skies. While I missed the peak of the shower, I was able to get out and shoot the following night while there was still some meteor activity. Sprague Lake provided a nice foreground, the calm air kept the lake glassy smooth to reflect the night sky -- as well as the lights of Estes Park, just outside the National Park to the east. (It's supposedly a good place to see moose, but alas none showed up even at their favored feeding time before sunrise.)

The first photo is a composite of seven frames, each a 60 second exposure (Nikon D850, 14-24mm f/2.8 @ 14mm f2.8, ISO 1600). In all but one frame a mask in Photoshop reveals only the meteor trail. Otherwise the motion of the sky (actually a reflection of the motion of the Earth, of course) would make confusing, trailed star images as in the second photo. The same meteors are there, but overwhelmed by the overlapping star trails totaling about 45 minutes of exposure.

The first one was taken at Sprague Lake in Rocky Mountain National Park a couple of years ago. It's a composite of seven exposures, the ones with meteors out of many frames in a time-lapse spanning a few hours. One of them is a nice bright meteor. I like the night sky landscape even without the meteors, which are a bit hard to see. You may notice that the streaks are roughly radial, looking like they originate from a point in the sky. This is because in reality the Earth is moving through a stream of small rocky fragments along a path in the Solar System that was the orbit of a comet long ago. As we plow through the stream, we see meteors coming at us, their paths foreshortened into short streaks, something like driving through a snow storm. The name Perseids comes from the apparent source of the meteor paths, in the constellation Perseus. Despite the glow on the horizon is from Estes Park, the town just outside the National Park the sky there is quite dark so we see part of the northern Milky Way and many faint stars, even reflected in the calm lake. 

2019 Perseid Meteor ShowerEven one day after the peak of the Perseid meteor shower, I was able to capture many meteors over several hours on the morning of August 14, 2019. There may have been many more, fainter ones, but the nearly full Moon illuminated the sky. And this was taken from my patio with a fair amount of ambient light from suburban Bloomington, Indiana.

This is a composite of 34 frames from a stationary camera shooting a time-lapse sequence for about 5-1/2 hours. To compensate for the motion of the sky, the frames were aligned in Photoshop so that the shower's "radiant" and the meteor trails retain their true position in the field. Meteor trails were isolated using a Photoshop mask and superimposed on a single frame to provide the star background.

Nikon D850, 20mm f/1.8, each frame 14mm, 30 sec., f/4, ISO 1000, Pluto trigger.

The second one was taken in my back yard in Bloomington, Indiana last summer. This shows many more meteors despite brighter skies than in the Rocky Mountains because this was closer to the peak of the meteor shower, and likely there were just more meteors that year. Here you can see the radial pattern of the paths more clearly. This too is a composite of many frames from a time-lapse sequence. I aligned the images as well as I could and then used a mask to reveal each meteor streak against a single frame of the starry sky.

But sometimes you just get lucky.
 

Carina Nebula

In reality, this is a vast expanse of space covering some 50 light years across, an incomprehensible 300 trillion miles. Yet it's so far away that it appears only about 1/2 degree across in the sky, roughly the diameter of the full Moon. It took about 50 separate Hubble frames to cover this area.

In contrast to Hubble's narrow view of the sky, our eyes take in a very wide view and most normal camera lenses we use, even the longest telephotos, also show a relatively wide field of view. This was brought home to me recently when I started to take more photographs of the night sky with my relatively limited equipment. We're not talking about some of the large, high-end telescopes that many amateur astronomers have these days. I have been using off-the-shelf cameras and lenses mostly, taking a lot of wide-angle views of the night sky, including the Milky Way, mostly in the background of interesting landscapes. I enjoy these juxtapositions of the more familiar Earth-bound scenes with the larger universe that becomes visible at night (from a dark site at least). The lens I use mostly for these is 20mm focal length which provides a whopping 84x62 degrees wide field, much wider than what we normally take in visually. But it is able to capture a large stretch of the Milky Way in a single frame.

Milky Way over Hickman Bridge

This photo shows the Hickman Bridge, a natural stone arch in Capitol Reef National Park in Utah. I was able to find a place to stand where the Milky Way would rise above the arch. Capitol Reef is quite remote so the sky is very dark. So dark in fact that taking photographs exposed well for the dark sky also captured some detail in the landscape, illuminated only by the light from the sky.

But sometimes you do want to zoom in to see details more clearly, as you may want to capture distant wildlife, so you need to use a longer focal length. Aside from a small telescope of 1250mm focal length, the longest telephoto lens I have is 500mm, the long end of a 200-500mm zoom, an amazing piece of equipment. Its field of view is 4.2x2.7 degrees with my full-frame DSLR. By comparison, the field of view of Hubble's WFC3 camera in its visible-light mode (UVIS) is 2.3x2.1 minutes of arc, that's a factor of about 82 in linear scale (a minute of arc is 1/60 degree). I'd have to put a 57,600mm lens on my camera to equal Hubble's field of view, kinda outside my price range at the moment.

Lately I have been using an 85mm lens to photograph the sky, considered a moderate telephoto, which provides a field of view of about 24x16 degrees, much wider than that 500mm. It works well to capture some interesting details of the Milky Way. I got super lucky recently while using this lens to photograph an interesting part of the Milky Way known as the North America Nebula. Can you see the pinkish shape in the center of the photo below? It looks vaguely like the map of North America, rotated with north to the left in this view. That bright streak is a meteor, a chunk of rock that hit the Earth's atmosphere and vaporized, creating a glowing trail. This happened to be during a meteor shower known as the Lyrids, named for the constellation Lyra.

Lyrid Meteor and the North America NebulaThis was taken from Brown County, Indiana on a cold, clear, moonless morning of April 22nd at 3:04am EDT with a Nikon D800 DSLR, converted to record H-alpha, and Rokinon 85mm f/1.4 lens on an iOptron CEM25P mount. It is a composite of six exposures, each 30 sec., f/2.8, ISO 1250, post-processed in Adobe Lightroom and Photoshop. All the frames were registered and median-combined, and the frame with the meteor was added back in Lighten mode.

Here's another meteor captured the same night using the same equipment. I wasn't expecting to get meteors in these relatively narrow pieces of the sky. They are rare enough that you usually need to see large expanses of sky to have a chance to see many of them. I was instead aiming at another celestial target familiar to astronomers, a galaxy known as the Whirlpool. Astronomers also know it as M51, in a catalog assembled long ago by Charles Messier. In this view the galaxy is quite small and hard to see at this scale.

If we crop the image down to about 100 pixels wide around the galaxy, it looks like this. Not an especially impressive result, but I was surprised that with this lens and camera there was any detail at all. We can tell that there are actually two galaxies, and that the larger one on the left has spiral structure. With a longer telephoto lens or a telescope with longer focal length there would be much more detail, using the same camera.

Whirlpool Galaxy

This is the same as zooming in or cropping an image to single out a tree in a wide landscape.

Now here is the view of the Whirlpool Galaxy from the Hubble Space Telescope. That's a lot of detail! The difference between this and my rather pathetic version is a much longer focal length that provides enormous magnification, though limited to a very small field of view. In fact Hubble's view was even smaller; this image was constructed from six separate views, stitched together in a small panorama. It also helps enormously that Hubble orbits above Earth's atmosphere so it does not suffer from the distortion and absorption the air imposes on the light.

Milky Way over Yellowwood LakeThis early-season Milky Way photo was taken 30 March 2020 at about 6:00am EDT at Yellowwood Lake, in Yellowwood State Forest, Brown County, Indiana. It is a panorama stitched from five vertical frames taken with a Nikon D850 DSLR and Nikon 20mm f/1.8 lens. Exposure for all frames was 10 sec., f/2, ISO 2500. The frames were post-processed and merged in Adobe Lightroom. The three morning planets are visible to the right of the trees on the left: Jupiter, Saturn, and Mars.

It's always a treat to see the Milky Way and I always enjoy getting a decent photo of it, even though I have to miss some sleep. Unfortunately, in winter the brightest part of the Milky Way is not visible, it's above the horizon only during the day then. But early spring brings not only warmer weather, flowers, grass to mow, etc., it also means the Milky Way will be visible again, though only in the wee hours of the morning. Of course it has to be clear and dark to see the night sky, both of which are pretty rare where I live, in Southern Indiana. As the year progresses, the Milky Way rises earlier each night and by the end of summer is visible all night so it's a little easier to get out earlier to catch it.

I was able to take advantage of a clear, moonless night recently, dragged myself out of bed at 3:00am, and got to a favorite spot not too far from home. Yellowwood Lake in beautiful Brown County, Indiana is a good location to see the sky: close to home but far enough from the medium-sized town of Bloomington to the west and smaller Nashville to the east so the lights don't entirely dominate the night sky and within a state forest, with minimal development. The lake is conveniently oriented with it's length oriented mostly north-south so it provides a nice foreground view to complement the sky. If the conditions are right, the lake also reflects the stars making for interesting compositions.

I'm pretty sure the glow on the horizon is from the Louisville, Kentucky. I was surprised that an urban area of its size would be that noticeable from about 100 miles away. But there is not very much development between here and there other than small towns and rural security lights. Also these are deep exposures to capture the faint glow of the Milky Way, which pick up stray light pollution just as well.

Technical details:
This photo is a panorama stitched from five vertical frames taken with a Nikon D850 DSLR and Nikon 20mm f/1.8 lens. Exposure for all frames was 10 sec., f/2, ISO 2500. The frames were post-processed and stitched in Adobe Lightroom. The three morning planets visible to the right of the trees on the left are Jupiter, Saturn, and Mars.

ISS Lunar TransitThis is a daylight pass of the International Space Station passing in front of the Moon. Thanks to the ISS Transit Finder (https://transit-finder.com/), I learned about the location and timing of a pass visible from close to home. Fortunately the weather cooperated, though there were passing clouds right before the event that came awfully close to scuttling it.

This is a composite of ten frames shot in high speed continuous mode starting a second or so before the predicted pass: Nikon D850, 200-500mm f/5/6 lens, 500mm, 1/400 sec., f/14, ISO 250. Processed in Lightroom, composited in Photoshop with lighten layer blend mode.

This is a daylight view of the ISS passing in front of the Moon. It's quite a challenge to capture; one of those times where being at the right place at the right time truly counts. It took only about 1/2 second for the ISS to pass in front of the Moon. It happens only a few times a year for any location and at any given time only from within an area on the ground a few miles wide by maybe 50 miles long, much more tightly constrained than a total solar eclipse, but much more frequent. Thanks to software called the ISS Transit Finder (https://transit-finder.com/), I learned about the location and timing of a pass visible from close to home. Also, the Moon is actually fairly small in the sky so needs a lens with high magnification (long focal length) to project any size in the camera. And it's a challenge to focus and set the exposure, but there's plenty of time to take test exposures while waiting for the main event. Oh and the weather has to cooperate too of course. I was afraid that some clouds would scuttle the view today but there was a patch of clear sky just at the right time. This was my second try for such an event; the first one, with the ISS transiting the Sun, failed. And this one almost did too, one of the two cameras I used did not fire properly.

With a bit of enlargement, you can even see some detail in the ISS, which seems remarkable to me considering the relatively minimal equipment used to take the photo. The ISS is about the size of a football field and was 279 miles away at the time. 

ISS Lunar Transit DetailThis is a daylight pass of the International Space Station passing in front of the Moon. Thanks to the ISS Transit Finder (https://transit-finder.com/), I learned about the location and timing of a pass visible from close to home. Fortunately the weather cooperated, though there were passing clouds right before the event that came awfully close to scuttling it.<br/><br/>This is a composite of ten frames shot in high speed continuous mode starting a second or so before the predicted pass: Nikon D850, 200-500mm f/5/6 lens, 500mm, 1/400 sec., f/14, ISO 250. Processed in Lightroom, composited in Photoshop with lighten layer blend mode.

Technical information: this photo is a composite of ten frames shot in high speed continuous mode starting a second or so before the predicted pass: Nikon D850, 200-500mm f/5/6 lens, 500mm, 1/400 sec., f/14, ISO 250. Processed in Lightroom, composited in Photoshop with lighten layer blend mode.
 

Comet Atlas (C/2019 Y4)The brightening comet ATLAS (C/2019 Y4). It's the greenish fuzzy dot near the left edge of the frame. It doesn't look like much now but is expected to brighten dramatically in the next few weeks. Tech: Nikon D850, 85mm f/1.4 lens, 24 exposures, 30 sec. each, f/1.8, ISO 2000, iOptron SkyGuider Pro. Processed in Lightroom, median-combined in Photoshop.

Look toward the right, past the field of stars and see two whitish fuzzballs that are famous galaxies: M81 above, a classic grand spiral, and M82 below, a more bizarre specimen. Detailed images (from Hubble and other powerful telescopes) show material flowing out of the galaxy, driven by activity deep within. 

Not to be melodramatic, but here's an example, in a single image, that shows the vast depth and scale of the universe. The little green comet is part of our Solar System, a visitor from the cold, vast depths beyond Pluto. It's relatively nearby, "only" 100 million miles away or so at this time. The stars filling the frame are much farther away, but still relatively close in cosmic scales, up to a few thousand light-years away, in our Milky Way Galaxy. The two galaxies, M81 and M82 are quite a bit farther, 12 million light-years away.

Tech: Nikon D850, 85mm f/1.4 lens, 24 exposures, 30 sec. each, f/1.8, ISO 2000, iOptron SkyGuider Pro. Processed in Lightroom, median-combined in Photoshop.

For more information about Comet ATLAS and how to see it, go to https://earthsky.org/space/how-to-see-bright-comet-c-2019-y4-atlas

Indigenous culture spans many centuries in Mexico, long predating the arrival of Europeans. On a recent trip to the southern state of Oaxaca I was struck by the timeless designs on many of the remaining ancient buildings. Many intricate stone panels adorn the large ceremonial and residential structures at sites such as Mitla including tomb interiors, courtyards and exterior walls. Fortunately many of these remain spectacularly preserved, though many structures were dismantled or destroyed, their stones used to construct newer buildings including European-style churches. 

Mitla TombInterior tomb in the Mitlan archeological site. Mitla, OaxacaZapotec architecture in Mitla, Oaxaca.
Looking closely, it became clear that the intricate designs are not carved into large stone blocks, but 3-dimensional mosaics of small blocks pieced together into large, regular patterns creating a very pronounced texture when viewed from some distance. There are many different designs, but all with a consistent, geometrical aesthetic set into very large, multi-story structures themselves made from much larger stone blocks with astoundingly accurate masonry. I had to keep reminding myself that these were produced many centuries ago, all with hand tools.

As remarkable as these structures are, it is fascinating to see the very same designs used in other artforms still being produced today in the same area. Weaving is one of the most important industries in Oaxaca, particularly in the town of Teotitlán del Valle, where several multi-generational families carry on the traditional practices (https://www.etsy.com/shop/MBWeavings).

They produce rugs and other items from local wool, processed and dyed in-house and woven on large, traditional looms by hand. Though traditional natural dyes are still used, they also use synthetic dyes with more vibrant colors.

Drying Yarn

During a recent trip to Oaxaca, Mexico I found a number of very interesting doors. One interesting feature of the architecture there is the frequent use of ornamentation and bold colors. Many of these doors are old, from Mexico's Spanish-colonial period, but there are sites that are much older than that, dating from centuries BCE from the Zapotec, Mixtec, and Axtec cultures. The bright mid-winter light made many buildings, including their doors and windows pop and sparkle.

Entering the ChurchCatedral de Nuestra Señora de La Asunción, Oaxaca City. Oaxaca City Church GateEntrance to the Templo del Carmen Alto, Oaxaca City Panteón Municipal, TeotitlánEntrance to a cemetery in Teotitlán, Oaxaca. OmarA small cafe in Teotitlán, Oaxaca. Teotitlán DoorResidence in Teotitlán, Oaxaca. Teotitlán Church DoorwayDoorway in Iglesia Preciosa Sangre de Cristo, Teotitlán, Oaxaca. Church Gate, TeotitlánGate of the Iglesia Preciosa Sangre de Cristo, Teotitlán, Oaxaca. Mitla Curch DoorDoor of the Templo Católico de San Pablo Villa de Mitla, Oaxaca. Mitla DoorwaysDoors in the Mitla Archeological Site. Kitchen DoorKitchen door of the Las Granadas Hotel in Teotitlán, Oaxaca.

I also photographed the total eclipse in 2017, with better equipment, digital color cameras. 

Total Solar Eclipse SequenceA sequence of the total solar eclipse of August 2017 including the "diamond ring" and the corona during totality.

Starry Night over Yellowwood Lake

This part of the sky holds secrets that we cannot see with naked eyes, even on the darkest nights and clearest skies. Some of these secrets involve light emitted by hydrogen atoms in great clouds of gas and dust (technical term: nebulae) in between the stars in our galaxy. We can see the brighter stars, but much of the light emitted by the clouds of hydrogen is too red for our eyes to see. Even most cameras cannot record this light because they include a filter that blocks infrared and far red light. Recently I had one of my DSLR camera bodies modified to swap out the infrared-blocking filter to one that transmits the hydrogen light. Using long exposures, and a bit of post-processing, these vast clouds of gas become visible. This is a close-up of the upper right area in the first photo showing mostly only Orion and the neighboring Monoceros constellations.
Orion & MonocerosA composite of eight exposures, 1 minute each with a Nikon D800 converted to record the light of hydrogen and 50mm f/1.8 lens on an iOptron SkyGuider Pro mount to keep the camera pointing at the same spot in the sky. Many large clouds of glowing gas in our galaxy are in this field: the Great Nebula in Orion (M42) in Orion's sword and Horsehead and Flame Nebulae just above in the belt are dwarfed by the much wider Barnard's Loop to the left and another large feature above. The fine Rosette Nebula is to the upper left and above another large complex including the Cone Nebula and Christmas Tree Cluster. Anyone very familiar with Orion will notice that one of his brighter stars, Betelgeuse (Alpha Ori) is dimmer than usual these days. It is known to be variable, but this is the dimmest it has been for quite a while and nobody is sure why. Stay tuned.

The brightest patch, the Great Nebula in Orion (M42), part of Orion's sword and the Horsehead and Flame Nebulae just above in his belt are dwarfed by the much wider Barnard's Loop to the left and another large feature above. The fine Rosette Nebula is to the upper left and above another large complex including the Cone Nebula and Christmas Tree Cluster. Anyone very familiar with Orion will notice that one of his brighter stars, Betelgeuse (Alpha Ori) is dimmer than usual these days. It is known to be variable, but this is the dimmest it has been for quite a while and nobody is sure why. Stay tuned.

Circumpolar Star TrailsStar trails over Boulder Mountain taken from the Larb Hollow Overlook on Utah Highway 24. This is a composite of 31 frames, 2 minutes each, for a total exposure of about 1 hour; Nikon D800, 14-24mm f/2.8 @14mm, ISO 800.