Michael A. Covington    Michael A. Covington, Ph.D.
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Popular topics on this page:
How Melody's self-portrait was made
Two PixInsight tips
Color casts in DSLR astrophotography and PixInsight
Music that Melody introduced me to
A photo safari to Braselton
Markarian's Chain
Moon (first quarter)
M56 (globular cluster)
M57 (Ring Nebula)
M13 (globular cluster)
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What is this a picture of?

A bit more photography for art's sake...


Caverns? Glaciers? Homage to Lyonel Feininger?

No, it's actually a close-up of my glass of Coca-Cola when sunlight hit the back of it. I took Melody out to dinner the other night at Amici at the Falls, a new restaurant across the road from FormFree. And snapped the picture with my iPhone.


50 years ago today: The Action Trav'lers

Half a century ago, on June 26, 1971, I was riding my bike to the Valdosta Public Library and got lost. I happened upon the headquarters of the Action Trav'lers, recognized the place from having been involved briefly in 1969, and was welcomed in by the founder, Robert C. Winter III, who remains a lifelong friend.

The Action Trav'lers were a unique youth travel club whose story (as of 1968) is told in this movie. By 1971 the organization had had expanded, was open to girls as well as boys, and was known as The Action Trav'lers rather than Adventuretours. The organization thrived through the 1970s and still exists as a way for alumni to keep in touch, but no longer conducts trips.

Many members spent a lot of time at the headquarters as volunteers, working on the converted bus, building and maintaining camping equipment, and helping to manage and publicize the club. I was delighted to be among people my own age with an entirely positive mindset — no cynicism — not a hint of rebellious adolescence — everybody wanted to team up and do something worthwhile. And people with all levels of talent were affirmed. Boys with disadvantaged backgrounds were often happy to discover that they could do any kind of good work and be respected for it; meanwhile, I did very specialized things such as editing newsletters and fixing electronics. At first I ignored the travel altogether but eventually went to Mexico with them in 1972.

This was a turning point in my daily way of life because it gave me a way to get out of the house during the summer and on Saturdays. In middle school I had spent long, boring days in the house when school was not in session. Not any more. The Action Trav'lers were accessible by bicycle. Actually, so was the whole town; Valdosta has flat terrain. From 1971 to the COVID lockdown in 2020, it was my habit to get out of the house, when possible, for at least a couple of hours every day.


45 years ago today: Braselton

Uploaded 1 day early. If you are reading this on June 20, don't worry, the space-time continuum of the universe has not been disrupted.

On Monday, June 21, 1976, Melody and I undertook a "photo safari" not to Africa, but to Braselton, Georgia. Melody wanted to photograph an old house in the picturesque little town, and she was trying out her new Minolta and also carrying her father's Fujica rangefinder camera. I was trying out my new car (a bright green, almost Day-Glo green Buick Century chosen by my mother) but was camera-poor — my Mamiya/Sekor SLR was being repaired, my father's Petri rangefinder was also not serviceable, and I ended up shooting Kodachrome in my father's Voigtländer Vito B, with no focusing aid or light meter, relying on Melody for exposure readings.


This was actually the first time I had ever done nature or scenic photography with anyone. Other people had enjoyed my pictures but never joined me in taking them. My photography had been a solitary pursuit. So I was delighted that my beautiful companion and I could do photography together. And she wasn't just keeping me company; she was doing exactly the same kind of photography, on the same technical level.

We went up Highway 53 from Winder, stopped at a lake on the Jackson County line, stopped again in Braselton, and then continued to Gainesville for lunch at Shoney's. When we headed back to Winder, sudden rain caused steam to form on the road, something I had only seen in the much hotter climate of South Georgia.

Here are some of Melody's pictures, starting with the house that had caught her eye:





And here are some of mine:





That's not the order in which we took the pictures; the order was lake, meadow, Braselton, and (on the way back) fog. Many times the two of us took almost identical pictures.

We thought about re-enacting the trip this week, but after surveying the route on Google Street View, I concluded that things have changed too much. The lake in Jackson County is still there and apparently little changed, but after multiple hip operations, Melody may not be in shape to walk down to it safely, and anyhow, if it's little changed, there's no point in photographing it again.

Braselton, by contrast, has been turned into a tourist attraction, which means it looks neater, cleaner, and just a bit more artificial; were glad we caught it when its quaintness was all natural. Click here to have a look around.

The beautiful meadow, I have not been able to pinpoint. Fortunately, Melody took one good picture of it and I took three, all practically identical. The sequence of my film frames tells me it is on Highway 53 between the pond and Braselton, probably in this general area. The exact spot may have been disguised by construction or by the growth of trees.

I haven't tried to identify where we took pictures of steam on the road, since those places aren't very distinctive-looking. My notes from that day don't even tell me whether we returned to Winder on 53 or took what had been Melody's usual shortcut home from college, turning onto 211 to bypass Braselton and enter Winder nearer her home.

This is the last of the 45th anniversaries I will write about here. A few days later (after one more dinner date with Melody), I went to Oxford University for a six-week summer program; when I got back, it was the beginning of my last year at UGA and her first, and we could finally spend a lot of time together. By then, we were inseparable companions, but I was going to spend five of the next six years away at graduate school. I was deeply unsure whether I had any right to even wish that we would still be together after that. Fortunately, Melody was patient, a slow courtship suited both of us, the story unfolded at its own pace, and we were happy at every stage of it. We had a great year together at UGA, followed by a five-year long-distance relationship, and then we got married and lived happily ever after.


The moon, in some detail

Finally, some astrophotography! The combination of clear weather (which has been rare lately) and a day off for Juneteenth (enabling me to stay up late) led to a good astrophoto session on the night of the 17th.

I used my iOptron GEM45 mount (which served me well), Celestron C8 EdgeHD telescope, f/7 reducer, and Nikon D5500 (H-alpha modified) camera. And although designed for deep-sky work, this setup also happens to give quite sharp images of the (nearly) full face of the moon. And since the moon was high in the sky, I took aim at it and snapped away. The result wasn't bad:


Surprisingly, shutter vibration didn't blur the picture. This is a stack of five exposures ranging from 1/250 to 1/640 second.

Why is this phase of the moon called "first quarter" when we see half of it, not a quarter of it? Because it's a quarter of the way around its orbit, from new, to first quarter, to full, to last quarter, to new moon again.

Globular cluster M56


This distant cluster of stars, in the direction of the constellation Lyra, is known mainly for being old and lacking interesting peculiarities. (Well, I have at least one of those things in common with it; you get to decide which.) Globular clusters are clumps of stars on the periphery of our galaxy (or any galaxy).

Why do I say "in the direction of the constellation Lyra" rather than "in Lyra"? To make it clearer that Lyra isn't a place. It's a patch of sky comprising everything that is the right direction to fall within it, whether near or far.

Stack of eleven 2-minute exposures.

The great globular cluster M13


Here is the great Hercules globular cluster, one of the finest in the sky, together with a completely unrelated distant galaxy at the upper left corner. (I got photobombed, so to speak.) In front of the cluster you can see a set of dust lanes that resemble a Mercedes logo or upside-down Y (more about that here).

Stack of fourteen 2-minute exposures.

The Ring Nebula


This is an example of the good tracking I was getting with the GEM45 (and autoguiding with a 60-mm guidescope and PHD2 software in multi-star mode). Stack of 17 2-minute exposures.

The Ring Nebula is a "planetary nebula," which has nothing to do with planets except that in the telescope, it looks a bit like a faded-out planet. It is actually a cloud of gas expelled by a dying star — which survived the process and lives on, right in the center.

About halfway from the nebula to the upper right corner of the picture, you can see a faint smudge that turns out to be the distant galaxy IC 1296. I could have made it more visible by processing the picture differently, but then the nebula would have been too bright.


Short notes

An unexpected holiday: On slightly more than one day's notice, FormFree gave us today (Friday, June 18) off for Juneteenth, the new federal holiday commemorating June 19, 1865, when the Emancipation Proclamation was promulgated in the last of the Confederate states, Texas, ending slavery in the former Confederacy. (It took a few months longer to end slavery in the slave states that had not seceded and in the Indian Territory.)

Juneteenth had already been celebrated by African-Americans for decades, and I don't mind making it a federal holiday at all. (Some do, perhaps because it involves admitting that white people have done wrong.) But the logistics of implementing a holiday on such short notice are challenging. I doubt that all businesses that would normally close for it, or go into holiday mode, are able to do so this year, simply because it's too late to change plans. I don't even know if it's officially a holiday this year, since the legislation was only signed yesterday.

How goes the war? COVID-19 in Georgia alternates between flat and declining; it's definitely not on the rise. I wonder if there are factors that make measurements inaccurate, or make them read high, when the total number of cases is small.


Water Music

Continuing in the series of 45th anniversaries, today marks a visit with Melody that gave us a piece of theme music. On this date in 1976, she and her sister invited me to swim at a small neighborhood club near their house. Afterward, her mother gave us a snack of watermelon, and there was music playing on the stereo, Händel's Water Music, which I had never heard but which was very much to my taste. (It was composed for a stately procession of ships.)

Melody's mother quipped, "Water sports, watermelon, and Water Music," and that's the name by which we have remembered that day ever since.

Click here to hear Händel's Water Music.




This picture is homage to our longtime friend, artist Scott Pope, whose dramatic paintings of clouds have inspired us.



Goodbye, old chairs


While I was in the UGA Main Library today both to get a book and to take a picture that I've just added to the May 1 entry, I saw what may be the last of the library's mid-century chairs on the way out.

These chairs predate my arrival in 1973; they probably go back to the opening of the (older part of the) Main Library building in the 1950s. Or at least the opening of the new part of the building in 1974. The ones you see here are on the 7th floor (art and photography); I've sat in some of them over the years. The new chairs look more comfortable, but it's the end of an era.


Another almost-postwar note

Melody and I went out for dinner again the very next evening — last night, June 11 — and saw, at Longhorns, a waitress who had waited on us regularly at Dos Palmas two or three years ago.

And at the (still depopulated) Science Library the other day, I saw a librarian I hadn't seen since the lockdown.

These are the kinds of connections that I thought would be lost — not people we know well enough to seek out socially, but acquaintances we are accustomed to seeing in our daily lives. There will have been at least a year and a half worth of turnover and attrition before normal life resumes.

My own post-COVID life will be quite different from before, simply because Formfree now has an office building (just north of Molly's Coffee in beautiful suburban Watkinsville) and I spend much of every day there. I'm ramping up my involvement with the company.

Meanwhile, Georgia's COVID infection rate is flat or even (according to one estimate) now increasing. I still think this is a Memorial Day bump. I'm not sure what to do about it; I'm fully vaccinated and not part of the problem, but something like two thirds of Georgians are refusing to be vaccinated because they swallowed some garbage about magnets or space aliens.


College students are not all legal adults

Long, long ago, in a university far, far away, I, as a faculty member, found myself remonstrating with a university bookstore manager that he should not prominently display Playboy and Penthouse while we were being visited by a Catholic high school, whose bus was parked outside.

He argued that the university was a completely adult environment, and that I should get used to it.

My argument, which convinced him, is that his contract to run a bookstore on campus probably included some duty not to embarrass the university.

But I should have simply pointed out that the students are not all legal adults! We have always had some regular college students who were under 18. Melody was 17 during her first year of college. I was 16 my first year, 17 my second year. And, of course, there are plenty of high-school and middle-school students walking around the campus for good reasons.

I realize, of course, it's not illegal to promote girlie magazines to minors, it's just obnoxious. But the fact that these people are minors means you can't claim we're an all-adult environment. That has much wider implications.

The university's sexual harassment policy might also kick in. The bookstore is on campus, not an off-campus private business. The university has rules against showing people sexually explicit material that they don't want or need to see, regardless of their age.

Almost-postwar life

One nice thing about taking Melody to dinner last night was simply seeing lots of other people doing the same thing. During the pandemic, social life, even the shallowest parts of it, has consisted only of intentional encounters with individuals, as one would have in a sparsely populated rural area. Although moderately shy, I've always been accustomed to, and felt energized by, the energy of the crowd, the hum of the hive, the sight of other people enjoying each other's company. That was missing.

Meanwhile, after a heartening decline, Georgia's COVID infection rate has flattened out (R=1.0) and we hope there's not about to be another flare-up. Most likely, we are looking at a "hump" from Memorial Day gatherings, which will peak in a couple more days. But we're not sure.


45 years ago today: Dinner date


Melody's and my first dinner date to a restaurant was June 10, 1976, and today we marked the 45th anniversary by going out for a very similar meal. Back then, we went to Manuel's, a Mexican restaurant on Baxter Street that was already the favorite of both of us (she had been there with her family, who would drive over from Winder for it, and I had been there with friends). Manuel's is no longer there, so we went to La Parrilla. (Which, Melody points out, was also the last restaurant we had gone to before the lockdown.)

After dinner that evening in 1976, I brought Melody home to meet my mother at our house on Cleveland Road. This was actually the first time my mother had met any of my college friends, though she met a handful of them later. I wasn't sure at the time exactly what either Melody or my mother thought of the other. Fortunately, they got along well.

After dinner back in 1976, at my (parental) home, we sat on the sofa, listened to Neil Diamond's music from Jonathan Livingston Seagull (I think the music is better than the film, which is better than the book), and, together, looked through the first 5 volumes of Grooks, epigrams by Piet Hein that we have been quoting to each other ever since. Tonight, we did the same, with two small differences. Now we also have the sixth volume of Grooks. And although we still have the vinyl record that we listened to back in 1976, we don't have a record player in the same room as the sofa, so we listened to the music on a laptop computer via YouTube.

Tonight's dinner out was our third since the pandemic; the first and second were at Chicken Salad Chick a few weeks ago, and at Firehouse Subs in Commerce on a shopping trip last Thursday. Before the pandemic, we ate out maybe five times a week.

I thank Roy Green for the copy of the old newspaper ad.


50 years ago today:
A church youth program does a good thing

Fifty years ago, on June 8, 1971, the youth program of my church, First Baptist Church of Valdosta, did a very good thing. It amped up the youth program to meet the young people on the right educational level. To be specific, June 8 was the first day of PROBE, an evening discussion series for young people with questions, which was the beginning of a greatly enriched youth program.

Before starting PROBE, the church invited people to submit questions to discuss. They also polled us about some suggested questions. One of them was, "Did God intend for men to go to the moon?" and I don't think it got any votes. The actual discussions were about how to apply Christian values and insights to everything from sex education to the Vietnam War.

This is part of several changes instituted, as best I can tell, by Rev. Mac Weaver, who was at the time the new minister of education (and is still there!).

As a child, I had found Sunday School boring and had noticed that it seemed to be pitched lower than the grade level of the children in it. That's because the denominational textbooks were aimed at rural churches (the ones that need the most help from the central organization) and were not addressing a college-bound population. This is what First Baptist, Valdosta, addressed.

Our Sunday School got reorganized. Instead of "You are in this room because you turned 14 between such-and-such dates," it was "Would you like to take our course about the Holy Spirit?" and things like that. I found it much more congenial. College-bound students who know what a logarithm is and what DNA is have a right to know about such things as how the New Testament canon was formed. I ate it up. At last I realized that church life was going to be part of my education.

As the summer progressed, we had group Bible studies that led to real discipleship. The key goal of a youth program should be to give young people a sense of ownership of their spiritual condition, so that they're not just going where their parents said to go and doing what their parents said to do. Personally following Christ has to be part of learning to think for yourself. If it isn't, you'll stop doing it when you start thinking for yourself.

The fatal mistake that some youth programs make is to pretend that the young people are never going to grow up, or at least haven't started doing so. Just keep them entertained, keep them from falling in with bad crowds, and — bore them to death! Or at least drive away the ones who aren't crowd-followers.

The early 1970s were a crucial time for young Christians. There was an upsurge of evangelism that some later called the Fourth Great Awakening. It was essential to tell young people that Christianity was not the same thing as materialism, secular conservatism, or middle-class conformity; we had a right and a duty to think critically about such things, not swallow them whole. And there was a new wave of musical creativity that we needed to tap into. In the face of popular music that was sometimes unprecedentedly ungodly, it was important to show that God can be worshipped with new voices.

And I am proud that, that same summer, Melody, whom I had not yet met, was on tour with First Baptist Church of Tucker, Ga., performing in a youth musical called Show Me Jesus with exactly that message.

Show Me Jesus, a.k.a. Show Me, was composed by Jimmy and Carol Owens. You can hear a recording of it (not Melody's performance) at this link.

Some of you will know that I think that later, too many people didn't outgrow the youth program and failed to connect fully to historic Christianity. I wrote about that back in 2019 and extremely alert readers may notice I've just quoted some of my own words. But in the 1970s, a new type of youth program was just what we needed, and it's what we got. Hats off to Rev. Weaver and all who made it happen.

A plant by the fence


Here's another bit of art. I can't take much credit; the beauty of plants always intrigues me. Nikon D5300, zoom lens at 55 mm.


Why were my galaxies green?
Color casts in DSLR astrophotography and PixInsight

[Updated 2023 March 26.]


I've written a few times about color casts in astrophotos taken with my DSLR; see this Notebook in May 2020, this article on Cloudy Nights, and this note just a few days ago. But I need to bring everything together and also explain a new discovery.

First key point: Contrast-stretching an astrophoto increases the color saturation. Color differences are, after all, just differences in brightness, across channels. Accordingly, a relatively mild color cast often comes out garish and overpowering when the image is viewed with screen stretch.

Second: It is common for an image to have some color cast due to the sky background (brownish or bluish depending on the kind of streetlights nearby). And that is not the problem I want to address here.

When you calibrate with flat fields, any of several things can happen.

If the flats have the same color cast as the astroimages, the color cast of the flats will correct the images, at least approximately. In PixInsight WBPP, this requires unchecking "Separate CFA flat scaling factors." And even then, it only works if you are not using a saved master flat. For consistency, therefore, I don't recommend doing it. So leave "Separate CFA" checked — that's my current recommendation.

If the flats have a different color cast than the astroimages, they will shift the color of the resulting image toward the complementary color of the cast in the flats. That is, cyan flats will give you reddish images. That is the situation I corrected — by filtering my flat panel — in this article.

If the flats are perfectly neutral gray, or are decolorized (by checking "Separate CFA flat scaling factors," which is default in WBPP), then they will not affect the color of the astroimages.

That sounds desirable, right? Actually, it gave me green pictures, and I finally figured out why!

When you open a raw camera file with Photoshop, or with PixInsight (set to deBayer it), the camera color balance data will be used to adjust the strength of red, green, and blue. (This is a setting you can get to by double-clicking on RAW in Format Explorer.)

When the image is calibrated and processed, or if you open it raw and then deBayer it, the camera color balance data will not be used and you will get an image with a strong color cast. Don't worry, all the data in the image is intact, and you can correct the color balance in Histogram Equalization or various other ways.

Specifically, images from my Nikon D5500 come out green. And I figured out why. The sensor in that camera picks up more light on the green pixels than on the red and blue pixels. Color cameras commonly do. They render green about half a stop brighter than red or blue, until color-balanced.

Some of you are thinking, "Of course it's green; the pattern is RGGB, and there are twice as many green pixels as red or blue." No; that's not it; PixInsight and all other deBayering algorithms are not that dumb. They average (not add) the two greens to make RGB.


Look at this picture. This is a Nikon D5500 image of a flat-field source that is gray with a hint of red. In front, you see the deBayered image, which is green (screen stretched of course). In the background, you're looking at the upper left corner of the image, un-deBayered, greatly magnified. It looks like a checkerboard — the R, G, G, and B pixels are not equal.

Recalling that the pattern is


look at the four pixels in the upper left corner. The G pixels are lighter because they actually registered more light. The color balance data from the camera does not make it through processing (and perhaps ought not to be used even if it did). The green color is correct, at least as far as the deBayering algorithm knows. It is present when you render all the data that is actually in the pixels.

What's the right thing to do? Let it be green, and then color-balance it in processing. Several ways to do that are described here.


Music that Melody introduced me to

[Repeatedly updated.]

Most of the music titles here contain links to YouTube, where you can hear the music. Many of them will show advertising first.

I paid little attention to popular music in middle school, high school, and college; I was too busy discovering classical music. As a result, though I heard the most popular of the popular songs, I neglected them and only liked a few of them. Also, since childhood, I had had a strong preference for instrumentals rather than vocals. To me, one of the high points of popular music ever was Paul Mauriat's "Love Is Blue" (1968). I think my preference for instrumentals reflects the questionable habit of using music as background for reading or study rather than giving it my full attention.

A third factor is that, in Valdosta, popular music came to me almost solely via the local top-40 radio station, and it struck me as rather commercial — telling teenagers what to like so they'll buy it — and hence not extremely trustworthy. It would have been very different in a big city with a local musical culture and a variety of radio stations seriously interested in music and in getting to know their local audience. And for Melody, in Atlanta, it was.

Melody had appreciably more interest in popular culture, was more inclined to give songs her full attention, had access to much more on the radio, and had friends who could suggest things to listen to. (Once, on the bad advice of a fellow seventh-grader, she bought a heavy metal album.) She liked vocals more, and, as an artist, had much more inclination to try to find value in music even if she didn't actually find it pleasant. I had the much more naive idea that music always needed to be superficially enjoyable.

Another difference was that we shopped for records differently. A vinyl record album cost $5 to $7 back then, which is $50 in today's money. My mother had no interest in music, and we had been on a very tight budget for a while after my father died, so in our family, we considered full-price albums an expensive luxury. I enjoyed listening to my father's jazz records and took it for granted that the phonograph was for hearing music we don't hear on the radio, not music we do. What few records I bought for myself consisted of bargain albums from discount bins, and they were usually poor. By contrast, Melody's father had a good record library of his own and taught Melody how to build one; the key point is that five or ten good albums are a better investment than twenty or thirty from the bargain bin.

My escape from the bargain bin came from discovering budget classics (such as this Nonesuch album). Unlike a cover performance of a popular song by an unknown band, a second-rate performance of a classic is usually very good. Not everybody has to be the Berlin Philharmonic. The Chamber Orchestra of Somewhere in Poland is often just fine.

Melody escaped from high prices a different way. She joined the Columbia Record Club and was able to buy major albums at large discounts. Perhaps more importantly, they published catalogues and brochures (no online samples in those days!) and she often had to choose albums sight unseen, or rather sound unheard, from the program notes. This led to interesting discoveries. It also led to her knowing the background of the albums, whether or not she had heard them. And it led to the occasional embarras de richesse, as when she got 14 albums in one shipment and still does not know if she has actually listened to everything on all of them.

Thus it was that, after dinner with her family on May 21, 1976, when we sat down to listen to her records, she had some worthwhile things to share with me. We started with the versatile team of Loggins and Messina. This is who had given us "The House at Pooh Corner" back in 1971; of course I had heard that. And also "Danny's Song." But what I didn't realize was that neither of those songs was very representative of their other work.

As best we can recall, Melody got out a brown-jacketed album and we started by listening to "Native Son" (and probably several of the tracks that follow it); that accounts for my impression, recorded in my journal, that Loggins and Messina were "similar to Simon and Garfunkel." Then, for comic relief, she got out a different album of theirs and played "Holiday Hotel" which starts out sounding like it might be about something disreputable, but it's actually about frugality, a trickster, and an over-advertised, overpriced motel chain of the 1960s.

After hearing more of their repertoire, I've concluded the best Loggins and Messina song, to my taste, is "Be Free." It has a fascinating instrumental section in the middle. The lyrics are good, too, and are very well delivered. There is one potentially offensive word (near the end, a couple of lines after "life is but a dream"), but since it expresses genuine disgust at a well-deserved target (drug dealers on the street), I'll grant it to them.

Next we listened to Rick Wakeman's fascinating "Myths and Legends of King Arthur" [corrected]. This is a kind of music that I later learned is called progressive rock, a term that I had heard but misunderstood. I thought progressive rock would be rock that had progressed further and was rockier than any other kind. Not at all! It is the use of rock instruments and techniques in music that ranges into other genres, and often steps completely over the line. For example, progressive rock includes perfectly straight performances of classical pieces on electronic keyboards. Emerson, Lake, and Palmer are the prototype for the genre; I was acquainted with their work but had never dived in, and neither had Melody.

Much later, around 1981, Melody introduced me to another progressive rock band, Sky, whose "Mozart Album" I particularly liked, though we started with "Sky 2." Sky broke upon her through hearing one song from that album, the Bach-inspired "Toccata," on an Atlanta radio station while driving on I-285.

Through me, classical music came into Melody's life in a big way; she had been acquainted with it but had not gone into it very deeply. In a few days I'll tell you how Händel's "Water Music" came to be one of our theme songs. We went to concerts at the University. She took a music appreciation course there — something I wish I had thought of doing.

But the most important musical experience we ever had together was when we were walking by a stereo in a Radio Shack in Santa Anita Fashion Park as newlyweds in the fall of 1982. What Melody heard first was "Dancing Flames," part of Mannheim Steamroller's album "Fresh Aire IV," but I think that by the time she came and got me, the music had moved on two more tracks, to "Embers," and the beauty of it almost made my mouth drop open. From then on, "Fresh Aire" I through IV have been "our music," the first music that we discovered and came to enjoy together, simultaneously. Mannheim Steamroller may be outside the bounds of progressive rock, completely into something else ("new generation music" or "new age music," not related to "new age" spirituality or superstition). It was a breath of fresh air (pardon the pun) to hear something that was designed to be beautiful from beginning to end. The composer, Chip Davis, has talked about this explicitly as one of his values.

I would be remiss if I didn't mention the late Dan Fogelberg. Melody has always enjoyed his music (and went to a live concert of his with her sister while I was away in graduate school); I have dipped into it but not listened systematically (but as of August 2021 I'm changing that). "Our song" is his love song, "Longer."


45 years ago today: Melody's high school graduation


On Friday, June 4, 1976, Melody graduated as valedictorian of Winder-Barrow High School. She had spent the year doing 100%-0% joint enrollment at Gainesville Junior College and so had not actually been in high school at all. Her family invited me to join them for the evening. Here's what I wrote in my journal:

I returned home [from my day at the University] early, around 4:15. After getting ready, I drove to Winder and was greeted by Melody, who was wearing a majestic white academic robe with gold trim. Unfortunately, the rainy weather required the graduation to be moved from the stadium to a very inadequate auditorium and only parents were allowed to attend. I therefore "did the honors" (as Mrs. Mauldin phrased it) of taking Melody to the school. Then I returned to their home to eat dinner as their guest. While Mr. and Mrs. Mauldin were at the graduation, Melody's aunt and uncle, who were visiting, together with Crystal (her sister) and I, set up a surprise graduation party for Melody. We blew up several dozens of balloons and placed them all over the den; Crystal also put up banners saying HAPPY GRADUATION and CONGRATULATIONS.

Around 9:45 they finally returned; Crystal, her uncle, and I each released a balloon which went darting through the air in the general direction of our arriving honored graduate. Then we had snacks and punch. Pictures were taken; Melody and I were photographed together for the first time.


Her valedictory speech was based on a quote from Ralph Waldo Emerson, "This time, like all times, is a very good one, if we but know what to do with it." I regret that I didn't get to hear the speech, and Melody's notes do not survive. But I'm sure it was a good one.

As graduation presents, Melody's parents gave her a Minolta SRT-101 SLR camera and 2× teleconverter, which we still have; I gave her a boxed set of Lewis's Perelandra trilogy, which we also still have.

Picture Picture


Red brick wall


Finally, again, some photography for art's sake. I took this picture back in March as a sequel to my picture of an alley near it in downtown Athens, Georgia. iPhone SE, postprocessed in Photoshop.

Colorful rosebush


Are the flowers the only colorful part of a rose plant? Not in this case. Also taken with my iPhone SE and postprocessed in Photoshop.

Sun illuminating trees from below


The picture doesn't do justice to the range of tones and hues that I saw with my eyes, but it's better than nothing. Nikon D5300, ISO 400, 1/320 second, zoom lens at 18 mm, f/9.


Markarian's Chain


Markarian's Chain is a striking chain of galaxies in the Virgo Cluster; M84 and M86 are the most prominent members. I've photographed it before, but this is a new try with newer equipment. Askar 200-mm f/4 astrographic telephoto lens, Nikon D5500 camera body (H-alpha modified), iOptron GEM45 mount using PEC. Stack of 21 2-minute exposures at ISO 200. I rendered this picture as monochrome (black and white) and left it a bit grainy to make it easier to see faint galaxies. Every little smudge on it is bigger than the whole starry sky that you can see with the unaided eye.

Two PixInsight tips

Avoiding strong color casts when stacking color images

Note: For more context see June 7, 2021.

It is common for color (CFA, OSC, DSLR) images to have a strong red, green, or blue color cast when calibrated and stacked, even though PixInsight can open the raw image files and decode their color correctly. In the past I've written about how to remove a strong color cast, but now we have another tool in our kit, making it easier to get a correct stacked image in the first place.


Use the Weighted Batch Preprocessing script, and, in the Control Panel, uncheck "Separate CFA flat scaling factors." When this is unchecked, PixInsight can use your flat fields (presumably color-neutral) to correct any disproportion in the strengths assigned to red, green, and blue. The pictures won't be perfect — you still need to do some color adjustment — but they won't be garish.

Preloading a set of process instances when PixInsight starts up

There is a small set of process instances that I like to have ready on my PixInsight desktop whenever the program starts up. Mine happen to look like this:


Each of them, of course, has settings already made in it so it's not quite what you get by choosing the item from the menu, and some of them have been renamed.

Initially, I created a PixInsight project (with no working file in it), saved it, and loaded it every time I used PixInsight, in order to get the same process instances on my screen each time. But there's a better way.

Create the process icons you want, and place them in convenient positions on your screen, and then select them all and save the selected set. This makes a file whose name ends in .xpsm and I saved mine in C:\Program Files\PixInsight\CovingtonPreload.xpsm. (I had to give Windows permission to write in that folder.)

Then I edited the file C:\Program Files\PixInsight\etc\startup\startup.scp, which is PixInsight's startup script, to add the following line at the end:

.open "C:/Program Files/PixInsight/CovingtonPreload.xpsm"

(note the forward slashes; this is Linux-compatible). Now the process instances load automatically at startup. If I want to change them, all I need to do is save them again to the same .xpsm file.

I thank "sreilly" on the PixInsight Forum for this tip, which was the answer to a question I asked there.

NOTE: When you uninstall and reinstall PixInsight, for example going from version 1.8.7 to 1.8.8, you must copy and preserve these files (they will be deleted), then put them back in place.


How Melody's silkscreen self-portrait was made


This picture, which Melody made in the summer of 1978, has hung in my dorm room and then my office, and now my home office, for most of the time since she made it. It's a silkscreen print. We think we have another copy of it that is cleaner, and I still hope to find it and make a more definitive digital rendering. But in the meantime, this is the story of how it was made.

The work was done in the Visual Arts Building on Jackson Street (Athens, Ga.), and I was present for some of it.

It's a silkscreen print. That means it was made by squeezing ink through a piece of fine cloth (probably synthetic nowadays rather than silk) that was mostly coated with material that would block the ink. Where there were openings in the coating, the ink went through the cloth onto the paper. This is the way most T-shirts are printed, but this print is on heavy paper.

Now then. The coating on the silk screen was a photosensitive emulsion. The technique was to project an image on it, and the emulsion would harden where light struck it. In the areas where no light reached it, the emulsion didn't harden and was washed out. Thus, the dark areas of the image, where there was little light, became dark areas in the print, where the ink went through freely. The emulsion is like a photographic negative, and then, when you print on light-colored paper with dark-colored ink, you get a positive.

So Melody projected a color slide (which I had taken) onto the emulsion-coated silkscreen using a photographic enlarger.

If there had been only one ink involved, that would be the whole story. But there were three. Melody made three silkscreens and used yellow, magenta, and cyan ink, in that order. The three inks were at least partly transparent so their colors could combine.

Now here's the key point: Although it's colorful, this print is not a color separation.

The colors in the print correspond to brightnesses, not colors, in the original image. The emulsions on all three silkscreens were the same, and so they responded to colors of light in the same way. The difference is in the exposure. The screen for cyan ink received the most exposure, to put the least ink on the paper. The magenta screen received less exposure, and the yellow one, less exposure yet, but in fact the magenta and yellow exposures were almost the same, so that much of the picture would be red (yellow and magenta combined).

Accordingly, the lightest areas of the picture are white (all three emulsions hardened), some areas bordering white are yellow (with all but the yellow emulsion hardened), many more are red (with neither the yellow nor the magenta emulsions hardened), and the darkest areas are deep bluish-gray (with no emulsions hardened and all three inks combining; if the inks were more precisely matched, they'd be black).

The explanation that I just gave doesn't fit the stained-glass window, which was partly manipulated by hand. Blockout material can be, and is, hand-painted onto silkscreens; it's the normal way to fix small holes or cracks in the emulsion, and you can even make the whole picture that way. There is also blockout tape, used at the edges of the screen. Using these materials, Melody made the stained-glass window more colorful. That is how, for instance, there are areas that pass only cyan ink, and areas that pass only cyan and yellow.

And now you know! (There is more about the process here.)

Note added Mar. 20, 2022: It's more complicated than that! This is not a print of a single color slide; it's a composite of at least two, plus some freehand alteration of the lower part of the window. Melody did a great job of "condensing" a tall stained-glass window into a smaller picture that matches our memory of the window better than it matches the window itself. We will eventually work out how it was all done!

If what you are looking for is not here, please look at previous months .