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2025 April 29 |
Per aspera ad M105 On the evening of the 28th, I photographed M105, NGC 3384, and NGC 3389 (right, upper left, and lower left respectively) and got absolutely wretched guiding with what should have been excellent equipment, so that only 75 of my 160 30-second exposures were usable. | |
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I ended up with a fine picture, despite the difficulties. In fact, look at the lower left corner; you'll see a trapezium of three stars and a fuzzy object, which is a 17th-magnitude galaxy. Then look a bit to its right, halfway to a bright star, for an even fainter, unnamed galaxy. This was with my new Altair 26C camera and Celestron EdgeHD mount at f/7. The problem was the autoguiding. I was using my usual Losmandy GM811G mount and iOptron iGuider guidescope (which performs well with this mount; it isn't too small; I often get 0.7" RMS guiding). For some reason, there was often a lurch of 4" to 12" in right ascension (the east-west dimension), often accompanied by some movement in declination; the movements in the two dimensions were (usually) similar enough to cast suspicion away from the RA motor, though not similar enough to completely exonerate it. Here is a small part of a guiding graph. The lurches averaged maybe 30 to 60 seconds apart but were not at any regular interval.
Just before the session, I had updated the Losmandy firmware to the latest version. I made sure its PEC was off, since it had never been well calibrated in the first place and might have been corrupted by the firmware upgrade. I varied the tracking algorithm in PHD2 with no useful results. So... Was it unsteady air? With some preponderance of east-west irregularity? I didn't see stars twinkling noticeably, which led me to conclude that my air was steady, as it was predicted to be by Environment Canada and Clear Sky Chart. But Environment Canada predicted unsteady air just a few tens or hundreds of miles from me, so maybe their prediction was off. Or was it a cable dragging against something? Possible, but I did rearrange all the cables with no real change in the symptoms. Or is the guidescope or guide camera loose in its holder? Possible, though I did my best to rule it out. I'm going to loosen and retighten everything the next time I get the mount out. Or is there something with the RA drive itself, after all? Am I about to relubricate the worm gear or something like that? I'll keep investigating. Oh? Canada? I post this screenshot from Truth Social, not as political commentary, but simply as a specimen of what a strange time in American history we are living through. Having seen it quoted, I tracked it to the source in order to confirm that it is authentic. Authentic, but strange!
I can't guarantee that it will be permanent, but presently, the link is https://truthsocial.com/@realDonaldTrump/posts/114415618596069518. ![]() ![]() |
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2025 April 27 |
Museum day Tomorrow will be the 49th anniversary of Melody's and my first date, and in honor of it, we've started visiting the Georgia Museum of Art every April 28. The museum is closed on Mondays, though, so we went a day early. We stumbled upon an outstanding exhibit, "Beyond the Medici", the Haukohl collection of Italian baroque art (see also this announcement as long as it lasts). There was also a new exhibit of Ukrainian paintings recently acquired by the museum. Next year will be the 50th! ![]() ![]() |
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2025 April 25 |
I don't dislike younger people... One thing that has not happened to me as I've gotten older... I have not developed a distaste for younger people. I'm not sure why so many others do. I don't want an all-over-50 social group or a senior citizens' church service. I like to mix with people of all ages. I certainly don't look down on other "generations." This may be related to the fact that I've never had much of a taste for organized all-male groups either. The real world is co-ed and multi-age. Nominal atheists? Fellow Christians: Here's something I was thinking about the other day... We know there are insincere nominal Christians, people who call themselves Christians, consider themselves to be Christians, but have no actual commitment to Christ. Are there also nominal atheists? Are there people who think they are atheists, but actually have a commitment to God, hidden deep down? What led me to think about this was an anecdote about Pope Francis. An Italian man, who was an atheist, nonetheless had all his children baptized. Then he died. His son asked Pope Francis if his father was in Heaven. Now I don't think I would have given the clear affirmative answer that the Pope did, but I do have an idea what he might have had in mind (and there may have been more evidence to back this up): By having his children baptized, this man showed that he wasn't really a convinced atheist after all. Maybe he was only a nominal atheist. In any case, as we communicate with atheists, we need to be alert to the possibility that some of them actually are believers, deep down, and are just looking for some obstacles to be cleared away. I do not think atheists are commonly secret Christians. I think there might be some people who have labeled themselves atheists without totally giving up their commitment to Christ. Maybe they are disgusted with other Christians' behavior, or maybe someone convinced them that rationality and higher education require them to give up faith. I have no idea how common this might be. It is something to look out for. ![]() ![]() |
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2025 April 24 |
Why there was so much witchcraft in the 1960s, 1970s, and 1980s One of the blessings of the Internet is that it is so easy to follow up references. When you find out about a book or a theory, you can also find out what other experts (or non-experts) had to say about it. That was much harder before the Internet; in those days, if you found something in, say, the Encyclopaedia Britannica or a book from a reputable publisher, you took it seriously, and you might not ever know if it was discredited. While following up references this way, I learned something important. Recall that there was an upsurge of interest in witchcraft and the occult in the 1960s, 1970s, and 1980s. I've found something that had an important role in starting it. A fringe anthropological theory, promoted by just a few scholars, claimed that the people tried for witchcraft in early modern times were perpetuating the ancient pagan religion of Europe, a definite religion that predated Christianity. This is called the witch-cult hypothesis. That is how we all heard of covens, black sabbaths, etc., as well as the notion that "witchcraft" was actually a religion which, instead of being evil, was as respectable the worship of Zeus or maybe Buddhism or Hinduism. And that is what modern-day Wiccans are trying to revive. A leading premise is that witches' spells were mostly fertility rituals, not curses. The witch-cult theory was advocated mostly by Margaret Murray, whose book was widely read, and whose theory got into the Encyclopaedia Britannica and was widely taken for fact. The problem? Evidence does not support the theory. It makes a good story, but it doesn't stand up. Not being an anthropologist, I refer you to those links, and any others you might care to pursue. Even if you believe the theory, you need to know it is generally considered discredited, much as it might have helped to sell books, movies, and even heavy metal music. An earlier piece of speculative anthropology, James Frazer's The Golden Bough, was still considered at least somewhat credible when I was an undergraduate. Not any more. It weaves together many different religions under a few themes such as Scapegoat, Dying God, etc., and ties Judeo-Christian to pagan religions. The problem is, it's all a creative stretch; it's not really where the evidence leads. Like many thinkers of his time (early 1900s), Frazer holds to an evolutionary view in which human thought progresses from magic to religion to science. We should consider Frazer a creative and influential part of early-1900s culture — not the key to ancient culture. He certainly tells a good story! Interestingly, Frazer played a role in the conversion of C. S. Lewis to Christianity. As I understand it, during his atheist years, Lewis considered Christianity just one more instance of Frazer's Dying God theme, no more credible than the others. Then he looked at it from the other direction: What if if really happened, and the other religions reflect the idea because they are reflecting and foreshadowing something spiritually as well as historically real? In fact, says Lewis, Christianity would be less credible if there were no foreshadowings or parallels in other religions. So he became a Christian. ![]() ![]() |
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2025 April 21 |
New printer After 15 years of faithful service, our Brother HL-5370DW printer that we bought in January, 2010, has become unable to sustain a Wi-Fi connection reliably, so we are going to give it to someone who will use it via USB connection. It still prints just fine, after 15 years of light use. Its replacement is a Canon D570 with similar printing capability plus a built-in scanner. The scanner is handy to have, and it can make copies at the touch of a button, in case we ever need them (a need that is rare nowadays).
But its biggest advantage is that it has enough of a user interface! There is a screen, a keyboard, and enough well-labeled buttons that we can make settings easily, and it can tell us what's wrong. The Brother printer had just a few lights and a couple of buttons, and for a while, I was misled because the "out of paper" light, together with another light, does not mean "out of paper" — it means "no Wi-Fi." Despite the telephone-style keypad, doubtless carried over from other models, the D750 is not a fax machine. That is just as well, because it does not require connection to a phone line. Fax is still used for confidential communications, especially medical records. I think one of the design flaws of the Internet is that security was not built in from the beginning and is still sorely lacking. Trump's messages for Palm Sunday and Easter As a snapshot of what America is like these days, I want to share with you, without further comment, President Trump's starkly different messages for Palm Sunday and for Easter, both as seen on his own social media site, Truth Social. These are direct screen captures. A message similar to the Palm Sunday message was also posted on the White House web site.
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2025 April 20 |
Feast Day of the Resurrection of Our Lord
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2025 April 19 |
Farewells Retired astronomer Fred Espenak, better known as "Mr. Eclipse," with whom I have corresponded but whom I have not met face to face, is now in hospice care and not expected to be with us much longer. If you have read anything serious about eclipses since about 1980, you have probably read something he wrote. He authored books of eclipse maps, web pages of eclipse predictions, and the like, as well as taking the pictures (there are two) on the 2017 eclipse commemorative stamp. (The picture of the moon becomes visible if you warm the stamp up with your thumb.) I hope his web site, which has details of many future eclipses, will be kept up. Closer to home, word has just reached me of the death of Larry Hatfield, retired from the UGA Department of Mathematics Education. I was his undergraduate lab assistant from about 1974 to 1977, helping people learn BASIC on a timesharing system, and he gave me great encouragement (and let me do a lot of exploration and self-education on work time). I last saw him at Presbyterian Village (a retirement home) just a few months ago, when I gave a talk on the history of amateur astronomy. He is missed by many. And another Valdosta Action Trav'ler is no longer with us. Lynn Connell, whom I knew only briefly but whom my sister knew better, passed away last month after a long illness. It is disconcerting to hear of the old age and death of someone I remember only as a young girl about three years younger than me. Lux aeterna luceat eis, Domine. ![]() ![]() |
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2025 April 12 |
Canonicals matter...
You may have noticed that Google and Bing are indexing the Daily Notebook considerably better than they used to. The reason is that I wrote a Python script that went back and added canonical links to every page on the site. I had already been putting these into new material since I changed to HTTPS in 2022 (details here), but I was seeing poor indexing of older material too. A canonical link tells the search engine the true or preferred URL of the page. My pages need them because they are accessible more than one way (HTTP and HTTPS, covingtoninnovations.com, covington-innovations.com, and covinnov.com, and in many cases, various redirections within my site). Google doesn't like to find the same page at more than one address. I wish Google and Bing were smart enough to figure this out for themselves. It shouldn't be hard. Their job is to tell us what is on the Web. In fact, I wish "search engine optimization" were not a thing, except insofar as it means simply putting, on your page, the words and phrases that people will search for (and not misleadingly). The search engine is supposed to index what it sees. ![]() ![]() |
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2025 April 11 |
The coming shortage of telescopes? At this moment, the United States and China have suddenly placed such high tariffs on each other's products as to stop trade almost entirely. I hope this will be reversed shortly, but if it isn't — or even if it is, but leaves lasting damage — amateur astronomy is about to change radically: The days of good, affordable telescopes may be ending, at least in the United States. Right now, all shipments from Celestron are suspended. Meade and Orion, as you know, went out of business for unrelated reasons a few months ago. Brands that we order directly from China, such as Askar, ZWO, and ToupTek, will of course be much higher priced than before. I suspect Celestron, Sky-Watcher, and other companies that use Chinese manufacturing will survive and sell primarily to other countries; their products will remain available here, at more than twice the price, while we envy our British and Japanese colleagues. Maybe smugglers will carry corrector plates and eyepieces sewn into their overcoats. If you have a telescope and are not actively using it, take note that your telescope is going to be in demand. Don't let good telescopes be discarded or given away mindlessly. Get them into the hands of people who will use them to learn and appreciate the sky. We will need a new emphasis on repairing, refurbishing, and modifying existing telescopes, as amateur astronomers did with WWII surplus optics in the 1950s. Lenses don't wear out. Electronic drive mechanisms do, and plenty of telescopes need to see new life on newer mounts, or even with their parts built into new optical systems. Telescope-fixing will become a more important part of the hobby, as it was decades ago. We also need to think about setting up instrument-loan programs at astronomy clubs, museums, libraries, and the like. This is particularly pertinent because a beginner often needs one kind of instrument for the first year or so, and then moves to something more advanced. Maybe that first year should be spent with a borrowed or rented telescope. You may have thought the Daily Notebook had ceased, but no, I've just been busy. I'm back! ![]() ![]() |
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