Beginning Astrophotography: Crescent Moonset

Computer-controlled, motorized telescope, dimly illuminated, aimed up and to the left at the distant crescent moon in the upper left, with a camera attached where the eyepiece should be at the back, using a baroque contraption.
Last night’s front-porch setup: Celestron NexStar 5 SE powered by a Celestron PowerTank Lithium and Sony α6300 camera connected using an E-mount camera adapter, aimed at the twilight moonset.

I had clear skies again last night, and I remembered to look for the Moon while it was slightly higher in the sky. I set my telescope up on the front porch shortly after sunset. The Moon presented an incandescent, imperceptibly fuller crescent facing the failing twilight.

Because it was higher, I had a better perspective, I had more time to take photos, I had more time to check my settings, and my photos had less atmosphere through which to photograph (meaning less distortion). And because the crescent was fuller, I captured more detail in my photos.


I always remember to spell out acquisition details in my astrophotography posts, but I’ve found instead people most often ask what equipment I use. I usually don’t list this in detail, both because I’ve usually already mentioned my equipment in earlier posts and also because I find that the exact equipment I used on a given night is partially convenience and whim, not meriting any particular recommendation or endorsement. My photos are within reach of all sorts of equipment of various kinds and prices, given practice and technique, and the last thing I want to do is give someone the impression they need to spend over a thousand dollars to do what a two-hundred-dollar telescope and a smartphone can do.

However, I’m going to try to make an effort to name what equipment I use now and in the future just because it’s so commonly asked. Maybe I’ll need to reference it myself in the future, too. So last night, I used

Those are the only four pieces of hardware I used last night.


I aligned the telescope on the Moon, which let it track roughly. This meant it needed periodic corrections to keep it from drifting out of view (once every several minutes). I concentrated on keeping the extents of the arc within the viewfinder.

View of the LCD display of the camera, zoomed in on a fuzzy section of the Moon, showing bright and dark sections divided by a diagonal line.
Using the Focus Magnifier on the Sony α6300, concentrated on a section of the Moon near its terminator to fine-tune focus.

Once it was centered and roughly focused, I used a feature on my camera called the “Focus Magnifier” to fine-tune the focus. I’ve found this to be indispensable. Using this feature, I zoom in to a close up view of some section of what the camera sensor is seeing. This way, I can make fine adjustments to the telescope’s focus until I get the best possible clarity available. I can also get a good idea what kind of seeing I’ll encounter that night—whether the sky will shimmer a lot or remain still. I was lucky last night to find good focus and good seeing.

Once focus is good, it can be left alone. I ensure that the adapter is locked tightly in place so that nothing moves or settles, keeping the focal point cleanly locked on infinity.

Then I turned the ISO up—doubled it. The Moon is a bright object, so I was not keen to use something I would use for a dark site, but I settled on ISO 1600. My goal was to reach a shutter speed of 1/100 seconds, which I did, without losing the picture to noise or dimness. A higher ISO works great at a dark site, but the Moon is quite dynamic, so I felt like I had less headroom. In any case, I used 1/100 seconds’ exposure and ISO 1600 for all my photos.

I captured a short 4K video before I began so I could capture the seeing conditions that night. I recommend viewing it fullscreen, or it will look like a still photo—the sky was placid as a pond last night.

After taking the video, I realigned the telescope slightly and, using my remote controller so that I could quickly actuate it without shaking the telescope, I took 319 photos, occasionally realigning to correct for drift.

Unfortunately, Venus and Mercury had already sunk too low to get a glimpse, so I packed it up and went inside.


I moved all the photos, in RAW format, to my computer from the camera. Then I converted them all to TIFF format. These two steps took probably something like an hour and resulted in seven and a half gigabytes of data.

Screenshot of a Windows program called PIPP, using two Windows, one showing the Moon highlighted in blood red, the other with several progress bars and a list of files.
Screenshot of PIPP in use, aligning the photos of the Moon and sorting them by brightness.

Because the Moon drifted, due to the rough tracking, the photos needed to be pre-aligned. I used a piece of software called PIPP for that. Without this pre-alignment step, the tracking and alignment built into my stacking software struggled mightily with the photos and created a mess.

Its output was another series of TIFF photos. I found afterwards that two of the photos were significantly too exposed, leaving many details blown out, so I excluded them from the rest of the process, leaving me with 317 photos.

Screenshot of AutoStakkert!3, a baroque program consisting of two windows, one with a large preview of the moon, the other with lots of graphs and buttons and inputs and multiple progress bars. It is 20% through "MAP Analysis."
Screenshot of AutoStakkert!3 stacking the best 50% of the Moon photos I took into a single image.

I opened these 317 photos in AutoStakkert!3 beta. After initial quality analysis, I used the program to align and stack the best 50% of the images (by its determination). This took a bit less than ten minutes and left me with a single TIFF photo as output.

Image stacking leaves behind an intermediate product when it’s complete, which is what this TIFF photo is. It’s blurry, containing an average of all the 157 photos which were composited into it. However, the blurs in this photo can be mathematically refined more easily using special filters. I used a program called Astra Image to apply this further processing. In particular, I used a feature it calls “wavelet sharpening” (which can be found in other programs) to reduce the blurring. I also applied an unsharp mask and de-noising.

Finally, I used Apple Photos to flip the resulting photo vertically (to undo the inversion which the telescope causes) and tweak the contrast and colors.

The Photo

Photo of crescent moon, slender, curving down like a bowl but askew to the right. Terminator stops just short of the Mare Crisium.
Crescent moonset taken at about 8 p.m., PDT, on 20 Mar 18. Composited from 50% highest quality photos of a set of 317 taken.

Click to view the photo in fullscreen if you can. There’s a lot of detail. The terminator of the lunar surface stops just short of the Mare Crisium (the Sea of Crises), the round, smooth basalt surface right about the middle of the crescent.

I can’t help but compare this one to the photo from the night before: what a difference a day makes. I had more time to work, more photos to take, and the benefit of yesterday’s experience to help improve.

Now it’s clouded over here again—Portland weather—and I can’t practice anymore for a while.

Beginning Astrophotography: Cheshire Grin

Thin waxing crescent moon, turned upward like an askew grin, surrounded by blackness
Waxing crescent moon setting in the west, photographed about 8:45 p.m. PDT (image stacked from thirty-nine individual photos taken by a Sony α6300 camera through a Celestron NexStar 5 SE telescope).

Before the waxing crescent moon set tonight, I caught its Cheshire grin among the firs in the west for a few minutes. Then it was gone.

I had to take my telescope (a smaller model, a Celestron NexStar 5 SE) down the sidewalk a little ways to get a view between the branches. I took as many photos as I could before it set too low in the sky, using my Sony α6300 camera connected to the telescope using an adapter without an eyepiece (the “prime focus” technique). They were photographed all at ISO 800 and exposed for 1/25 seconds. The photo above was stacked from the 50% best examples of those seventy-eight photos I took before the Moon subsided among the trees.

The Thing About My Name

I’m just Emily to my friends. I go by “Emily St” in writing whenever someone needs a longer name and there’s no strict, legal reason to give my whole last name. It catches some people up because “St” resembles the abbreviation for a bunch of things which have nothing to do with me.

In this case, “St” is only short for my last name—not “Saint,” not “Street,” not some other thing. I rarely give out the full version because I’ve found it’s unnecessary in almost every situation.

It’s surprising how often the full last name isn’t actually required. For years, I’ve managed to have mail delivered without my full last name—useful so I can know mail from people who actually know me from those who have me from some list. I’ve even had credit card transactions go through okay without the whole last name.

The idea that I might not be going by my “real” or “legal” name might cause someone consternation. But a “real name” is a slippery idea. It comes from a combination of assumptions about a person having a single, fixed name which is registered with a single, fixed governmental entity. This assumption is both relatively recent in history and only true in the simplest cases.

Not only may a legal name for a person vary over time, but even in a single moment, disagreement may exist among various legal entities about a legal name. For example, in the U.S., the moment a judge issues a court order granting a name change, you (and not some automatic process) must then take that name change order to all the various entities, public and private (Social Security Administration, DMV, bank, job, and so on) and get them all updated. Until you’re done, those entities disagree about your name. You can hold in your hand a driver’s license in one name, a Social Security card in another, and be totally in the right simply because of bureaucracy. They’re not even the same governments—one’s federal and one’s state. They have little meaningful responsibility to be in accord with one another (and any bills attempting to create a unified federal ID system have been resisted so far in the U.S.).

Then setting aside legal technicalities, a “real” name is just an idea that can coincide with a legal name or not, may be a single name or multiple. Used enough, a name may become someone’s legal name through sheer use—a name change by usage can be recognized legally as well.

There are people who convert their names through religion, use different names to assimilate culturally, or adopt assumed names for performance or pseudonymous reasons. Do you know Mozart’s “real name”? There’s an entire Wikipedia article about it. Would you be surprised to hear Beethoven introduce himself as Luigi or Louis, depending on if you were in Italy or France at the time?

The process of name change continues today. SAG-AFTRA rules discourage name collisions, so performers often choose new names under which they perform. Names also may have marketing or homage purposes. Diane Keaton loved Buster Keaton. You know Tom Cruise and not Thomas Mapother. Harry Houdini’s greatest escape might have been from the name Erik Weisz.

Seen through the prism of those contexts, what’s a “real” name?

As for why I use “St” and not some other abbreviation, I have a couple of reasons. First, “S” on its own would be even more confusing, I think. It’s less unique and might look like (in handwriting especially) like I’m just pluralizing my first name.

I also liked the way it looked when I signed it. I could cross the final flourish with a downstroke.

Scripted signature signed as "Emily St"

It began at my first tech job, where everyone was assigned usernames with three-letter acronyms, and for some reason, I was given “est.” I took to expanding that out—I can’t remember where exactly first—so my first name would be included.

It was pretty unique—easy to find as a username in places. It had no strong flavor of personality beyond being my name, so I probably wouldn’t tire of it. It was short. I managed to find a Web domain version of it online.

It sometimes confuses people that I shorten it this way—it’s not an initial, but it has no vowels, so it’s not a word. So sometimes I slap a big asterisk on the end—Emily St*—so it looks like something is omitted. (Putting a dot just made people say “Saint” or “Street,” as if part of the name got lopped off.)

That’s all there is to it—it’s just my first name and part of my last name. Nothing more. If you meet me, you can call me by my first name. If you really need to, you can sound out the letters “ess tee,” or just ask me my last name in person. (I don’t mind people knowing. I just don’t commit it to writing without a good reason.)

The Putty

A long time ago, when I was still a young buck in middle school, I was sitting around with my best friend at his trailer playing around, and I noticed a giant tub of what I took to be Silly Putty. Had to have been half a gallon of the stuff, pink, in a white plastic tub.

I thought: hell, yes, tub of putty. Gonna play with some putty. Gonna just scoop up a bunch of this putty, and—it’s a rock. I can’t shove my hand in. I only left finger dimples.

My friend told me it’s putty for physical therapy. “You squeeze it with your hand.” He dipped his hand in slowly, and it gave way to his light touch.

He explained, in middle-school words, that the viscosity makes it resist any flow faster than a fixed rate. You can’t make it flow any faster, no matter how much effort you put in. You can’t speed it up. To shape it, to squeeze it, it doesn’t matter how much force you put in. It always flows at the same speed.

I tried it. He was right. It felt soft and yielding as long as I applied very little force. If I added more force, it responded with obstinate indifference.

He was able to scoop it up smoothly because he allowed his hand time to sink in without shoving. I had thought of it as a liquid like any other that would simply make room for me as I pushed my hand in, but it didn’t. It pushed back. No effort on my part made a difference. Only time mattered.

Early on in my life, many things came easily to me. By that, I mean I learned new information easily and retained it. Some things came more quickly to me that did not come as quickly to others, and I was encouraged for it. I became accustomed to gliding through tasks superficially. I used my innate aptitude to move past unpleasant work as quickly as possible and attend to my interests. But this was an undisciplined way to live. The more I indulged only what came easily, the more I neglected other aptitudes I should have nurtured.

Later came problems for which I had less inherent aptitude—whether that meant synthesizing existing knowledge to adapt to novel situations, coping with uncertainty or ambiguity, training for physical tasks, or understanding and empathizing with new people. I had no ready-made shortcut here. When the time passed beyond which I could no longer ignore these problems, my instinct was again to find some other way to speed up my approach.

I had formed a habit of rushing of which I wasn’t even aware. I also didn’t like being caught off-guard and unprepared.

I figured maybe I could power through these new situations with a burst of concentrated effort. It made sense to me. If I could just summon up one good wind, I could quickly clear whatever problem and—ironically—avoid self-discipline again.

However, I often encountered frustration instead, and I tended to begin by blaming my frustration on extrinsic factors. At work, for example, I blamed the documentation, training material, or managers. I blamed the people around me for confusing me or misleading me. I dismissed or downplayed the subject’s importance. After a while, these excuses stopped working, and my frustration then turned inward. I ended up blaming myself.

My life—one with a relative lack of financial privilege until recently—had a way of forcing me through the hardship of those episodes, just to survive and make my way, and I’m better off for it today. I can look back at times when I finally saw what had to happen, acted on it, and grew from it. I only regret that I had to pass through so much needless, self-inflicted frustration, pain, and blame along the way.

I’ve begun thinking more and more about that physical therapy putty as I get older. I think we’re the putty.

To learn—to grow—we must change, in a real and physical sense, by reshaping our brains and (sometimes) our bodies. This is a process that takes time. Laborious effort makes no dramatic difference in the rate at which this happens, the way a novice cannot just throw a massive amount of weight onto the rack at the gym to get stronger right away. On the other hand, neither can it be slowed by failing to bring all our effort to bear—so long as we devote the time and commit to some progress—nor initial lack of innate ability. We inevitably change as a function of time, provided we keep going, bit by bit, every day.

I have thought about this as I learned guitar. I thought about it when I learned French. I thought about it when I taught myself to juggle. I thought about it as I tried to train my eye to see through a telescope. And I thought about it as I recognized the pattern of discomfort I move through as I begin a new job. As long as I kept at it, I improved—usually just about at the same pace from one experience to the next.

I learned that new kinds of growth came from applying myself and then just waiting, and from accommodating within myself the discomfort of that waiting.

I have often avoided uncertainty in my life out of fear, I think. I’ve never been encouraged to be uncertain or doubtful. Not having the answers makes me vulnerable because it undermines the very thing that set me apart early in life and made me feel more capable. With that vulnerability then comes discomfort because I am unkind to myself when I notice I’m unable to meet my own expectations. Worst of all, it feels inescapable in the moment: there’s just no way to get easy answers, an easy fix, a magic word. It’s tempting to believe—after half a lifetime of being addicted to all the answers coming so quickly—that you’re failing, and it’s your fault.

However, I believe uncertainty, discomfort, and self-forgiveness are precisely the traits I need in order to grow beyond superficial knowledge acquisition, so that I may find kindness and connect to new things and people I could not have done when I was younger. Cultivating these traits allow me to surrender myself in the present to the passage of time and all it brings—and eventually to new circumstances and possibilities I would not have had otherwise. There are matters of experience which I cannot touch intellectually, no matter how hard I try.

The hell of it is, I still don’t know how I will do these things yet. I think that’s okay for now, as long as I keep trying.

(I am grateful to Amy Farrell and to Sophie for their constructive feedback on my earlier drafts of this post.)