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Daily Notebook
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2020 January 28 |
Astronomy is a science, not just a hobby It's going to sound as if I'm deliberately taking the wind out of people's sails. But I've heard from several frustrated beginning amateur astronomers lately, and looking at the cause of the frustration, this needs to be said: Astronomy is a science, not just a hobby. When we look at the sky, we're looking at the universe itself, not some kind of man-made entertainment. That is the great thing about amateur astronomy, and also the challenge. The sky isn't just a gallery of pretty things to look at — it is the universe. That means amateur astronomy is a lot more like laboratory science than other hobbies are. Not everybody has to be an amateur astronomer. But if you don't enjoy astronomy at all, you're going to find amateur astronomy frustrating. Yes, there's math in it; astronomy is a mathematical science. And when we use telescopes, we're doing applied physics. You don't need a graduate-level or even college-level knowledge of the physical sciences, but you do need at least a bit of inclination toward them. Note: I am not saying not to use a computerized telescope or a computer. But understand what your instruments are doing for you. Don't treat the telescope like a cable TV box that is supposed to bring in any view you want, regardless of physical constraints. That's the road to frustration. For example, I think every amateur astronomer should read a college-level astronomy textbook and absorb at least the easier parts, including knowledge of how the earth's rotation makes the sky seem to move. That is not a gob of trigonometry that only your telescope's computer can keep up with. It's a simple rotation that you can grasp intuitively, and learning about it should be fun, not a chore. The same goes for the earth's revolution around the sun. An amateur astronomer should be proud of knowing exactly what is meant by equinox, solstice, precession, and similar terms. The same goes for the astronomer's tools. If you don't care to understand why a telescope forms a magnified image, and what determines its field of view, you're missing something most of us enjoy. A telescope doesn't just show us things; it puts basic laws of physics in our hands. That's why so many of us invent optical gadgets, or at least appreciate other people's inventions. Inventing the telescope is a job that's not yet complete. If things of that sort don't appeal to you, there's no shame in it, but amateur astronomy probably isn't what you're looking for. Most other hobbies deal only with man-made things; many deal only with things specifically made to entertain the hobbyist; but amateur astronomy confronts the whole universe and the laws of nature. |
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2020 January 27 |
Is Betelgeuse rebrightening? My eyes tell me Betelgeuse has stopped fading and is again slightly brighter than Bellatrix. My camera doesn't agree. Some observers, including me, think Betelgeuse was fainter than Bellatrix around January 22, but it may have rebrightened. My impression by eye (with glasses on and also with glasses off, to defocus) was that it is about 0.2 magnitude brighter than Bellatrix now (evening of Jan. 27). But the camera doesn't agree. This picture of Orion is deliberately out of focus to make it easy to compare the brightnesses of bright stars. Betelgeuse is the orange one at the upper left. Most of the time it is almost as bright as Rigel (lower right), but for the past few months it has been unusually dim. When I photographed it on Dec. 31 it was almost the same brightness as Bellatrix (upper right), but then it dimmed further.
Measurements on this picture, however, show that Betelgeuse is not quite as bright as Bellatrix. The camera's response to the spectrum may not be the same as that of human eyes or a proper V photometer. 8-second exposure at f/5.6 with Canon 40-mm f/2.8 lens, unmodified Canon 40D (a camera old enough to be in high school!), and iOptron SkyTracker. |
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2020 January 24 |
Quick updates — I'm still here! The last ten days have been a whirlwind of activity. No time for pictures or hyperlinks right now, but I can at least tell you what's going on... One big thing is my increasing involvement with FormFree, which I've been part of, in a minor way, almost since the inception. I'll write more about this soon. It's keeping me busy. We've also had major repairs to our roof and drainage system and to a window in my workroom, which, thank goodness, doesn't have to be replaced yet. And I've gotten a new lens. Nikon has replaced the 18-35mm AF-S "kit" lens with a new 18-35mm AF-P lens that autofocuses faster, autofocuses silently (important for videos!), and has a more advanced optical design. More about that soon, I hope. I also upgraded Word, Excel, PowerPoint, and Visio to the 2019 versions. What's new compared to 2010? Mainly, faster startup, and much better display on high-DPI screens. The overall functionality isn't much different. However, Visio has a new file format (.vsdx, replacing .vsd) with easy conversion from the old one, and a much better user interface more consistent with the other software. I have been using Visio for 25 years, longer than Microsoft has owned it, and I have shapesheets with 1998 dates on them! Back then I built a very sophisticated set of electronic symbols and want to continue using them. I also built an optics symbol set and used it in illustrating two of my books. And another big thing — we are making progress on Sharon's chronic severe shoulder pain. Two doctors strongly suspect a condition which, although somewhat rare, is not at all mysterious or spooky; diagnosis and treatment can proceed. More about that too, as it happens! |
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2020 January 14 |
McAfee Antivirus deletes legitimate software [Repeatedly updated.] The latest excitement around Covington Innovations is that a user of my free software package EXIFLOG told me McAfee antivirus software wouldn't let him install it. To investigate, I bought a copy of McAfee Total Protection myself and installed it on my computer. Poof! My installed copy of EXIFLOG disappeared. McAfee said it had found a "Trojan" and apparently deleted the file. (Actually, it was "quarantined" — see below.) Whoa there. Norton Antivirus, Malwarebytes, and Microsoft Security had all checked EXIFLOG and found no virus. According to both Microsoft and McAfee, the whole computer was virus-free, except that McAfee thought there was a virus in the EXIFLOG executable. And this is the computer on which EXIFLOG was created — so where would the virus have come from? It was a false alarm. Some pattern of bytes in EXIFLOG happens to resemble some virus McAfee thinks it can recognize. I fault McAfee not only for the false alarm, but also for removing files without asking the user. What if I had no other way to get a copy of that file? The process for restoring such files was not obvious to me; see below. The rest of the story, so far, is that when I compile EXIFLOG in release mode with either Visual Studio 2017 or 2019, McAfee thinks it's virus-infected. But if I compile it in debug mode, which puts a few more bytes into the file for use by the debugger, McAfee gives it a clean bill of health. For now, I've compiled it that way and put it up for people to download. I have reported the problem to McAfee. Their documentation leads me to believe that false alarms are a common problem and that they rely on people to submit files to them that are falsely flagged, so they can make corrections. I have an ethical and legal concern, too. Falsely saying someone's product has a virus in it is slander. Are there legal remedies? McAfee's blunders could cost other people a lot of business — could even completely ruin a newly launched small product. The bottom line: Viruses are much less of a problem than they used to be, now that Windows has virus protection built into it. I do not believe there are many, if any, viruses that McAfee knows about and Microsoft doesn't. One of the products might get slightly ahead of the other occasionally, but I actually think vendors of antivirus products nowadays make money by giving you false alarms so you think you are being "protected" against constant hazards. How to restore files apparently deleted by McAfee To keep the window design neat and clean, McAfee Total Protection hides many of the things that you might urgently need to see. Here is how to restore files that disappeared during a virus scan. (1) Open McAfee Total Protection. (2) Click on the gear at the upper right, then on "Quarantined Items."
(3) In the window that opens, click on "Quarantined items."
(4) Click on each item you want to restore (or "select all") and click Restore.
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2020 January 12 |
Protection from alligator (clip) bites Here's a workshop hint that I picked up from Wranglerstar's video while I was looking at wire-splicing methods. If you have a "helping hands" tool with alligator clips, like this, put heat-shrink tubing on the teeth of the clips so they won't mar the things you clip them on. Otherwise they can put quite noticeable tooth marks on soft objects, including the insulation on wires.
Melody gave me this tool for our first Christmas together as newlyweds (1982). As I recall, it came from the Radio Shack just north of our apartment, in the shopping center at Rosemead and Las Tunas in San Gabriel, California; or possibly the Radio Shack in Santa Anita Fashion Park. (Southern California had a Radio Shack every couple of miles in those days.) She dubbed it "Leadfoot" even though its foot is actually made of steel. In honor of its 37 years of faithful service, I gave Leadfoot some maintenance yesterday, with new alligator clips and heat-shrink tubing on their teeth. The same tool is still made. Click here to get one. |
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2020 January 11 |
How to twist wires together to make a soldered splice Now for something completely different. People have stopped sending me military secrets and messages of alarm, and I can get back to doing what I enjoy — collecting useful knowledge and then repackaging it for you. In this case, a whole blog entry about how to twist wires together, with over 100 years of history. I've written about soldering and about crimp connectors several times. Today I want to address something even simpler: how to twist wires together to splice them. Most electronics books say very little about these important manual skills. The splices I'm about to describe are intended to be soldered. They do not have enough mechanical strength if the wires are just twisted together and taped — the wires could be pulled out. So don't skip the soldering step. If you're not going to solder, use some type of approved solderless connector. It's easy to twist wires together crudely, but I'm about to describe how to do it a bit more neatly and reliably than you otherwise might. The two splices I'm going to describe are both based on a pair of twisting motions, where you twist one way with your right hand and then the other way with your left:
The two twists are the two ends of a single helix — the wire doesn't reverse direction in the middle. Both of these joints are descendants of the famous Western Union lineman's splice, which can be immensely strong when made with strong solid wire. That is where we got the idea of using two opposite twisting motions.
The classic lineman's splice has a place in the middle where both wires run side by side to make sure solder reaches both of them. When it's 1915 and you're soldering with a gasoline torch and no flux, that can be an important precaution. But today, we have no trouble getting our solder to soak into the entire joint, and we can make it a little more compact. So... Modified lineman's splice This is for solid or stranded wire. (1) Strip insulation from both wires, about 1.5 to 2 times the total length of the finished splice. Cross them about 1/3 or 1/4 of the way from the end of the insulation. (Common mistakes are not to remove enough insulation, or to cross the wires too far out.)
(2) Wrap one end of the left wire compactly around the part of the right wire that is below the crossing.
(3) Complete the splice by doing the same on the other side.
Then solder, and you're done. This joint has only moderate mechanical strength before you solder it; the wires can be pulled apart, but the splice is not fragile and not likely to come apart accidentally, even with a good bit of movement. Mesh splice This is only for stranded wire, and it's easy to do wrong. Done right, it is a two-step process, and you can see that it is descended from the classic lineman's splice, although it has little mechanical strength until soldered. (I've seen many people do this, but you may find this video by "Wranglerstar" particularly helpful.) (1) Strip insulation from each wire for a length equal to the length of the finished splice.
(2) Splay the strands apart, either individually or in bunches.
(3) Push the wires together so that the strands mesh.
(4) Grip the left-hand end of the splice, and use your other hand to twist the right-hand end.
Here's what you'll end up with:
(5) Finish the splice by gripping on the right and twisting on the left.
Do not pull on the wires until they are soldered. The mesh splice is very easily pulled apart. And then what? By popular demand I'm adding the following pictures to show you what happens to a splice after the wires are twisted. First I add flux (to remove corrosion so the solder will adhere better):
Then I apply solder. The tip of the soldering iron needs to be clean and have melted solder on it for heat conduction; a surprising amount of this melted solder is taken up by the copper wires immediately, and more has to be added. But the solder that will make the joint is applied from the top while heat is applied from the bottom:
Here is what the splice looks like with most of the solder on; as seen here, it still needs a little more:
Next step is to slip a piece of heat-shrink tubing over the splice. (Trap for the unwary: If the other end of at least one of the wires isn't open, you need to hop into your time machine, go back to before you made the splice, and slip the heat-shrink tubing on, leaving it farther down the wire until it's needed.)
Next step is to make the tubing shrink. I use a special, small heat gun that I got at Radio Shack (back when there was still such a thing); other hot-air guns and even lighters will work.
And now you know the whole process. When great durability is needed, I sometimes add a second layer of heat-shrink tubing. Why did I do this? Not just to tell someone (who?) how to splice wires, but also to get experience illustrating things like this. The camera was my Nikon D5300, not entirely satisfactory because its self-timer is good for only 5 seconds and has to be set by pressing two buttons (besides the shutter button) before taking each picture. Five seconds is not a lot of time to go from pushing a button on the camera to holding the soldering iron and solder. I think I'll use the old Canon 40D for pictures like this in the future; fewer megapixels, but more professional features. But I did have an interesting time using Adobe Illustrator to make the diagram at the beginning, about twisting in two directions. |
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2020 January 7 |
A wild day on the Internet [Revised.] The Iran conflict seems to be bringing out the worst in everyone. Here are some of the cautions I have had to deliver on social media and forums today:
Never spread anything on Facebook or other forums unless you can personally take responsibility for what it says and where it comes from. There. Now if people will stop sending me alarming things, maybe I can get back to work. |
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2020 January 5 |
Computer security in wartime
[Updated again.] There has been a reliable report of at least one Iranian cyberattack today, with the expectation of many more. Reports are that cyberattacks are mostly directed at electrical utilities, city governments, and other sites where a break-in could harm a lot of people, but the level of computer security is not what it would be at a bank or other financial institution. Local governments, in particular, are often understaffed or careless about computer security. The modus operandi is reported to be password spraying, trying to break in by using lots of passwords that other people have used. Don't use a name, birth date, or local slogan as a password! You're not the only Harry, the only 2013grad, or the only Bulldogs fan. Not by a long shot! For the rest of us, some cyberattacks are going to mix indistinguishably with traditional kinds of computer crime — they may just be ordinary computer crime with foreign sponsors. Here's are some ways to keep yourself safe.
This is just my theory, but I think the bad guys already know who's easy to scam. They've been watching who shares groundless gossip, fake news, quack medicine, etc., on social media, and willingly give out personal information in response to "games" and "quizzes." Some people will pass along anything, or get involved in anything, just because words on the screen tell them to. Those people are willing servants of any enemy that comes along. See also January 7. |
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2020 January 1 |
The dimming of Betelgeuse Look at the constellation Orion in the night sky — it is now high in the southern sky around 11 p.m. — and in particular the star Betelgeuse.
If you've been looking at the sky for a long time, you'll notice something wrong. Betelgeuse is supposed to be brighter than that. Like many red supergiant stars, Betelgeuse has long been known to vary in brightness, with a cycle of about 400 days superimposed on another cycle about five times as long, but it is normally almost as bright as Rigel and now it's barely brighter than Bellatrix. To see how Orion looked five years ago, click here. That picture was not taken with Betelgeuse in mind, and the brightest stars are overexposed, but you can still tell that Betelgeuse far outshines Bellatrix. Not any more. Here's another picture of Orion from last night (around 0415 UT on January 1) with the stars out of focus so that none of them is overexposed and the brightnesses are easy to compare:
So what's going on? We have to remember that Betelgeuse is hard to observe visually — there are no nearby stars to compare it to — so really accurate measurements date only from recent decades. We know Betelgeuse has been varying as long as people have been looking at it. Today it is around magnitude 1.5. It apparently got that dim once in the late 1940s, though I don't have the specifics. So I am not sure it is unprecedentedly dim. But we should keep an eye on it. Betelgeuse is getting ready to explode as a supernova. It's likely to do that within 100,000 years or so. A few astronomers think it may happen much sooner. Not everyone agrees. |
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