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Daily Notebook
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2015 February 27-28 |
Live long and prosper, Leonard Nimoy
We mourn the passing of Leonard Nimoy, who played the character Spock on Star Trek. In the hands of a lesser actor, Spock could easily have been a shallow, obnoxious nerd. But Mr. Nimoy developed him into a character who was deep, sophisticated, and noble. In so doing, Spock in particular (and Star Trek as a whole) was an inspiration to young people who valued rationality and intelligence in a popular culture where it was fashionable to be silly and confused. He was a good antidote to the 1970s. I was not, myself, a committed Star Trek fan, simply because I didn't like (or see) much TV at all. But I willingly admit that Star Trek was the best thing on TV at the time. It was the only TV show that was free to explore speculative hypotheses about humanity and society, and in spite of that, it was unpretentious — did not present itself as a highbrow philosophy program. That, of course, is part of the point of being intelligent. If you are intelligent, you can say things that ordinary people understand. If you can't, maybe you aren't. Jupiter
Last night's equipment-testing session yielded one halfway decent image of Jupiter, in unsteady air, with a telescope that was actually a bit out of collimation (as I discovered too late). Celestron EdgeHD 8-inch, 3× Barlow, DFK camera, stack of the best 75% of about 3600 video frames processed with AutoStakkert and RegiStax. Autoguider saga — Whatever it was, it's fixed Last night (Feb. 27) we finally had clear weather, and I was able to address the problem with the AVX mount's autoguider socket. Conclusion? Whatever it was, it's fixed. It may have been a transitory bad connection. It might conceivably have been a transitory firmware problem, because what may have cleared it up was resetting the AVX autoguide rates. Most likely, though, it was a combination of backlash, lack of backlash compensation, and a slow autoguide rate, causing the mount to take about 15 seconds to respond to a correction in declination. (Relay 4 always failed, not Relay 3, because 4 was always calibrated right after 3, when the backlash from the prior opposite movement would be maximum.) On February 11 but not last night, the problem may have been exacerbated by a balance problem. During the testing I found it very useful to use a hand box with buttons on it that simulate the autoguider relays. Plans for one are in How to Use a Computerized Telescope. In fact, one that I built several years ago is presently locked up at Camera Bug with my Meade telescope that I was trying to sell on consignment. So I had to build another one. To conclude the test, I brought out the autoguider itself, got a good calibration, and then had it autoguide for about 15 minutes, tracking in both dimensions. [UPDATE, 2019:] In fact, this was nothing more than a notorious problem with AVX mounts — not really a defect, just a mismatch between expectations. The AVX has a large amount of backlash in declination, in its gearbox, not just its worm gear. This shows up when an autoguider calibrates itself by moving north, then south. The amount of backlash is so large that some autoguiders' software won't believe it. Actually, once measured and accounted for, the backlash is not a problem, but it causes calibration to fail. Remedies: Use a longer calibration period (30 seconds); make sure the declination autoguide rate is set to 0.8 or 0.9 rather than the default 0.5. |
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2015 February 23-26 |
Short notes Unending winter: Fortunately, I can work at home. We've had bad weather for weeks (which has kept me from testing the autoguider more thoroughly) and were at home because of snow, ice storms, or storm warnings part of the middle of last week and then again yesterday. This morning much of North Georgia has had a major snow and ice storm, but Athens was spared. We didn't know it was going to be spared — there was certainly plenty of sleet yesterday — so we didn't make any plans, and the public schools are closed today, although UGA is open. The weather today is actually decent (37 F, light rain) but was predicted to be much worse. LED bulbs: Although we have had one LED floodlight bulb for a while, last night I installed our first LED bulbs that were designed to replace conventional light bulbs. I'm pleased with how well they work. They come on instantly (unlike CFLs) and seem brighter than the 60-watt bulbs to which they were supposedly equivalent. Hints when installing LED bulbs: (1) Write the date on the plastic around the base; there may be a warranty, and you'll want to know how long the bulb lasted. (2) Put some grease on the threads, because you may not unscrew that bulb for 20 years. Bulb grease is sold at auto parts stores, but any general-purpose grease will do, and you only need a little. (3) LEDs are not harmed by being turned on and off a lot. That is one of their biggest advantages over CFLs. (4) Red LED bulbs (which we don't have yet) actually use red LEDs (not white ones with a filter), are very efficient, and are good for preserving night vision and for use as darkroom safelights. Unlike a safelight with a filter, a red LED cannot emit any light in the range that fogs photographic paper. So when I finally get my darkroom going again, there will probably be some red LED safelights added. Autoguider saga: No further developments; it has been cloudy! Either the problem will be irreproducible (because a stuck relay or bad connection didn't persist), or it's an electronic failure and the AVX mount is going back to Celestron. Click here for more. |
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2015 February 22 |
Tax, right, and wrong One of the surprises of adult life, for me, was finding out that the IRS simply takes my word about numerous things that affect my taxes, even things they would probably not be able to check even in an audit. I'm a conscientious person, so this is not a big problem for me. I also assume the IRS might sometimes check things in ways I can't foresee. But a different type of person must find the income tax returns to be a constant source of temptation, even irresistible temptation. That's one reason I don't like having a complicated tax code. But even with the simplest reasonable tax code, there would have to be rules for deductions of genuine business expenses, since we tax net income, not gross income, and the IRS would still have to rely on us to be honest. A subtle challenge is that some of the information we must report to the IRS involves matters of judgment, especially the difference between business and personal activities. Try as they might, the IRS can't give precise definitions of every situation. What we have to do is understand the intent of the regulations and then judge things the way an experienced accountant would who is experienced in making the same judgment. The goal is to be neither stricter nor more lenient than normally accepted practice. The idea is to conform to standards accepted by others, not make up your own interpretation, no matter how well-intentioned. So what do we think of people who try hard to minimize their taxes? It's easy to get the impression that avoiding taxes is a sleazy practice. But wait a minute — surely nobody has a moral duty to pay more taxes than the tax laws require, quirky as those laws may be. And if the laws give a tax break to people who don't deserve it, your grudge is against the laws, not against the people who follow them. But (as Teddy Roosevelt would say) "on the other hand, not so fast." My friend Owen Shelton passes along an important tip: Don't trust people who have "secret" or "special" ways to help you get a bigger refund. They might be wanting to involve you in tax fraud. That's a good reason to deal with respected, professional tax preparers and understand what you're signing. |
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2015 February 20-21 |
Income tax tips and misconceptions [Updated.] Thanks to some careful tax planning by Dennis Haynes of Williams and Guined, I'm going to get a small tax refund (about 0.5% of my income) this year, even after the ups and downs of running a small business. That's as it should be — I want a refund, but a small one. To get it, I keep a running estimate of my annual profit and make sure my quarterly payments follow a table that he calculated for me, erring on the high side early in the year. This is much easier than doing a full accounting of actual profits every quarter in order to get a quarterly estimate. In what follows, I want to share some tips and address some misconceptions about American income taxes. Some of this is new, and some of it reviews what I've said in earlier years. Tip: You probably need professional help. If you are a wage earner with no special deductions or anything unusual, then by all means do your own taxes. But if you have other income, substantial deductions, or anything that needs more than about 4 pages of forms, get expert help. And I don't mean buy software — I mean hire a human being. If you need only a little help, go to Liberty or H & R Block. If you have a small business or large deductions, you need a CPA. The reason? Accounting is not arithmetic; it is the interpretation of financial data, and when there are questions of interpretation, I want them to be decided by someone who is experienced, aware of controversies, and working for me. For a while I wondered why the government didn't do all the work for us, but then I realized that we're much better off having our own advocates. Tip: You also need to understand taxes yourself. I rely on my CPA to know things that would be off my radar, such as changes in the tax laws and deductions I would have overlooked. But I want to know the basic mechanisms myself. Otherwise I would manage my affairs badly trying to save taxes in ways that don't work, or I would put effort into gathering data I don't need while neglecting data that I do need. The IRS is actually a pretty good place to get basic information. Many of their leaflets and web pages are well-written and understandable. There are also good popular books about income taxes. I wouldn't take a genuinely disputed question to the IRS, though; you're much better off asking a CPA or tax lawyer. By the way, I don't blame the IRS for the complexity of the tax laws. They don't make them up! Congress does, and the IRS scratches its head trying to implement what Congress asked for. Last year, as part of a consulting job, I got an inside look at the implementation of a different set of federal regulations (in banking) and saw what an ugly process it was. Congress passed a set of poorly-thought-out exhortations — well-intentioned but not based on a good understanding of how banks operate — and the regulators had to make "implementing regulations" that banks could actually follow. It took several iterations and came out much more complicated than if Congress had consulted the experts in the first place. Now for misconceptions. Misconception: If you claim the home office deduction, you'll get audited. In fact, I've had a home office for 25 years and have never been audited. Here's what I think I'm doing right. (1) My home business is genuine; it's not a tax dodge for a hobby. The home office is genuine, too — a suite of rooms built for the purpose, and not containing beds or clothing or anything like that. (2) I'm telling the IRS the whole story. My Schedule C (business profit form) is not something thrown together at the last minute to account for a couple of Form 1099s. It reports the finances of my business in detail, including information the IRS would probably not have gotten any other way, such as income from small clients and foreign ones that don't report to the IRS. Misconception: You want a big tax refund. No; it's your own money; as far as possible, you want to receive it when you earn it! Listening to financial call-in radio shows, I'm surprised at how many people think of tax refunds as a source of income. "When we get our tax refund, we're going to buy a car." Why did you lend that much money to the IRS in the first place? My goal is to get a refund, but only a small one. I don't want to have to make an unexpected payment, so I err on the side of overpayment, but not by a large margin. You, too, can get with your payroll office and adjust your withholding so that your refund is small. After all, getting a tax refund is like finding a quarter in your car — the only person who could have lost it there is you! Tip: Don't count on your refund being the same size as last year; don't plan on it as part of your budget. There are always changes from year to year. This sage advice comes from my friend Owen Shelton, who also contributed an important tip that I included in the next entry. Misconception: You need deductions or a mortgage in order to lower your taxes. "Don't pay off your mortgage, you need the deduction" is the single worst piece of financial advice I hear people circulating. It doesn't make a bit of sense. Your income tax is something like 25% of your income. A deduction subtracts money from your income. So if you have a $1000 deduction, you save about $250 on taxes. And does it make sense to pay $1000 to save $250? No. When something is deductible, that's like getting a 25% discount on it, not like getting it free. Of course, if you already have an expense, and it's deductible, you should definitely deduct it. Medical expenses, mortgage interest, employee business expenses, what have you — if it's deductible, deduct it and save taxes. But only if it's money you already need to spend. Don't spend extra money just to get deductions. That's how it works regardless of tax brackets or tax withholding. If you can't do the arithmetic, get with someone who can. By the way, the mortgage interest deduction only affects your taxes if you file Schedule A and find that it saves you more money than the standard deduction. If your financial life is simple, the standard deduction might be better in the first place. |
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2015 February 18-19 |
Autoguider, episode 2 Continued from February 12. I tested the autoguider and cable indoors tonight. They are OK. The relays close reliably, and the cable does not have a discontinuity, not even an intermittent one. The remaining possibilities are:
It will be a while before I can test the mount under the stars; we are having unseasonably cold weather, have had one ice storm, and seem likely to have another shortly. Stay tuned. |
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2015 February 17 (Extra) |
Honesty and software bugs [Updated twice.] Do you remember the days when software often crashed with a "General Protection Fault" and a hexadecimal number that was no use to anyone? In those days, a lot of end users got the impression that software is inherently unreliable (like early color TVs, or any other immature technology) and nothing much can be done about it, at least in the short term. It is tempting to let customers continue in that false belief and never take responsibility for software problems. "You shouldn't expect it to work 100% of the time." That attitude makes life easy for the lazy programmer. "Don't bother us with bug reports." But in fact I agree with E. W. Dijkstra's recommendation that "bugs" should be called "errors." That's what they are. Human beings make them. They do not crawl in by themselves. And unlike machines, computer programs do not have unknown physical properties. A program doesn't fail because you didn't know exactly how strong a piece of metal was, or because one copy of it was a little weak in one place, or anything like that. It fails because the instructions in it did not tell the computer to do the right thing. Undiagnosable crashes were common back in the 1980s, when a lot of people were using the C programming language in an undisciplined way. The amateurish C style of the 1980s — spread in books and articles and from programmer to programmer — made excessive use of pointers (variables containing memory addresses) and created lots of situations in which the programmer could forget to initialize a pointer. There was a folk belief that every extra statement should be trimmed away, and that meant no "defensive code" (initializations or tests that you imagine aren't strictly necessary). Things have gotten better with the move to C++, which automates some of the pointer work in C, and, even better, Java and C#, which attempt to produce meaningful error information every time there's a crash. There remains some debate as to how much of this information you should pass along to the user. Some developers are tempted to keep it hidden, just as in the bad old days. My own practice is to be open and honest about program failures. Typically, any of my large C# programs runs in a try...catch block that intercepts all crashes and displays a message such as, "This program cannot continue. If the reason is not evident, please report the problem, and if possible, quote the following technical message: ..." If the crash is a FileNotFoundException or an ApplicationException, then the technical message itself should be understandable to the user, so that's what I display. Two afterthoughts. First, as Jason Young reminds me, words like "illegal" and "fatal" scare people. Don't use them if you can avoid it. Second, no software runs reliably on bad hardware, but customers probably overestimate the extent to which hardware is to blame. "I need a new computer; the old one has gotten slow." No, you don't; your software probably needs cleaning out; you probably have installed a lot of Windows add-ons and background processes that are taking up memory and time without doing you any good. I have seen programs crash or malfunction due to hardware problems, especially problems with high-end video cards. Because it's not the main CPU, the video card doesn't get tested fully every time the computer starts up. It can have subtle things wrong with it. Even then, though, the newest driver software for it should always be tried before you give up on it. Also, of course, make sure your computer tests its memory when you boot it up, or at least do this occasionally. Iced Today (Feb. 17) we are advised to stay home at least until noon because there's ice all over town, and trees have fallen across roads. There's no damage in our immediate surroundings, but it's still cold. The worst ice storms occur when the temperature is just above freezing and a misty rain is falling. Individual objects become colder through radiative cooling, and ice forms on them. Crack... snap... skid... The weather forecasters and news media vacillated about the situation all day Sunday. Yesterday (Monday), we cancelled a trip to take Melody to the eye doctor in Atlanta, but then I got out of the house and went to UGA for a research group meeting — and then came right back home because the temperature was falling sharply. Last night, we listened to the scanner radio and heard about trees and power lines falling at the rate of one incident every two minutes. We never lost power, but much of Athens is still without it. I'll work at home today. |
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2015 February 17 |
Mr. Contraction I just heard a radio commercial spoken by a man who was running words together in an odd way. He said you can't rely on "Sosecurity" and you need a "retiremaccount." I'm going to listen for it again... I'm in favor of conciseness, but that is not quite the way to achieve it. |
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2015 February 16 |
Dwarfs
Here you see (from right to left) a normal star, a red dwarf, and a white dwarf. The image is deceptive — you're not seeing the sizes of the stars, but rather their brightnesses. Each of these stars would be a tiny but bright speck if the image were sharper. In the camera, a star spreads out into a circular image whose size is proportional to the brightness. Nonetheless, the picture does show you that one star is normal-sized and the other two are smaller (fainter). This is the multiple-star system 40 Eridani (Omicron-2 Eridani); the three stars are close together in space and all about the same distance from Earth. The white one was the first white dwarf to be discovered. This is a stack of three 5-second exposures with the Celestron 8-inch EdgeHD. By the way, the plural of dwarf is dwarves in the works of J. R. R. Tolkien and dwarfs everywhere else. |
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2015 February 15 |
Short notes I spent some time last night (Feb. 13) doing a full disassembly and reassembly of my Lenovo Z570 laptop. Fortunately, Lenovo puts its service manuals on line. What had happened was that recently, I replaced the keyboard using video instructions that I found on a web site. Somehow I removed too many screws, and although I got the computer put back together, one of the screws that hold the bottom cover on would not engage, and its nut was flopping around loose inside. It turns out that what had happened was that the nut had broken loose from the plastic that it was molded into. In fact, the same thing had happened to the corresponding screw on the other side. Both of them bore essentially no load and had probably been broken (with the screw still in the nut) for some time, so I just took them out. The computer may be a little less solidly built than before, but it works. Its fourth birthday is coming up, so it may be time for a new one. I may need to explain that I never publish pictures or articles sent to me by other people. The Daily Notebook and my Facebook pages are entirely for my own work. There are thousands of good astrophotographers in the world, and if I accepted outside submissions, I might get hundreds per day. Eventually, there will be a Notebook entry in which I rant against the dumbing down of church music. Somehow, in evangelical churches, within the past decade the notion has gotten out that "to bring in the young people" you have to have a loud but mediocre rock band, performing this week's top 10 playlist from a commercial Christian radio station, and nothing else. I've watched as organ music, hymnals, choir robes, children's choirs, and handbells have been done away with. (Handbells are far from essential, but who can actively dislike them??) I think serious mistakes are being made. More later. |
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2015 February 14 |
M42 in EdgeHD
For comparison to yesterday's picture, here's the Orion Nebula (M42) at the f/10 Cassegrain focus of my 8-inch Celestron EdgeHD telescope. This is a stack of three 30-second exposures at ISO 1600 and two at ISO 3200 with a Canon 60Da. Because it's at f/10 rather than f/6, it shows less of the nebula, but because the EdgeHD system is being used as designed, the star images are sharp all the way to the corners. |
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2015 February 13 |
Old-style focal reducer on EdgeHD telescope For Friday the 13th, here's a picture taken by a technique that is not recommended. On my EdgeHD telescope I used an old-style f/6.3 focal reducer instead of the new f/7 one designed for EdgeHD. That's why the star images away from the center of the field are elongated. More here. This is, of course, the Orion Nebula (M42).
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2015 February 12 (Extra) |
SBIG STV autoguider down for the count Last night I encountered a problem using my SBIG STV autoguider (vintage 2000) with the Celestron AVX mount. Relay #4 (which is either south or north, I'm not sure which — telescope mounts differ) always produced "no move." I checked it not only with the regular calibration process, but also with the "Move" option under "Calibrate" on the STV. Fortunately, guiding corrections are normally east-west, and I had done a very careful polar alignment to eliminate north-south drift, so I simply carried on, guiding in one dimension rather than two. The troubleshooting process is going to involve the following: (1) The cable from the STV to the mount. Last night I tried reseating the connectors and swapping the cable from end to end; I also tested its continuity and couldn't find anything wrong. Nonetheless, since the cable is the prime suspect, I'm going to replace it. The problem may be intermittent. (2) Connecting an ohmmeter in place of the telescope mount, I will make sure that the STV can actually close all four relays and does not have high resistance. (3) I will make a handheld control box with pushbutton switches in it to mimic the STV's relays. Plugging this into the mount, I can test whether the mount is responding to switch closures, independent of the STV. (4) I will also reflash the telescope mount's firmware; there's an update available. If step (3) shows that the problem is with the telescope mount, and step (4) doesn't cure it, then the mount will go back to Celestron under warranty. It's much more likely, though, that the problem is with the 15-year-old autoguider or its cables. It is also very likely that the problem is intermittent. If it's a stuck relay, then simply moving the STV around might cure it. I may clean the relay contacts electrically by making them carry about 50 mA (much more current than usual) as they open and close a few times. Stay tuned as the story unfolds... Continued February 19. Click here for the conclusion, February 28. |
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2015 February 12 |
Jupiter's back
On a happier note, Jupiter is back in the evening sky, and late at night it is almost directly overhead, so that even when the air is unsteady, we get a reasonably good view. Here's Jupiter through unsteady air around 11 p.m. last night (Feb. 11), with my Celestron EdgeHD 8-inch telescope and a Meade 3× Barlow lens and DFK camera. Stack of about 3000 video frames, processed with AutoStakkert and RegiStax. This is not the best this telescope can do, not by a long shot. |
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2015 February 11 |
A friendly reminder This is a reminder I posted on Facebook this morning, and it is something I never thought I would have to say. It is against the law to threaten violence against other people. It's called "making terroristic threats" and you can go to jail for it. If you make the threats on Facebook or any other Internet forum, permanent copies will be kept in numerous places even after you delete them. If you are a gun owner, and if you talk about how you might defend yourself or your property, make sure that you never say anything that sounds like a threat to harm a particular person or group. If you are the recipient of a threat via Internet, first save and secure a copy of it, then go to the police. The Internet is not a separate world; the people on the Internet are human beings and are subject to the law of the land. I had to deal with a rather troubling incident this morning. Fortunately, it is over now, and fortunately, I was not the recipient of the threat. |
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2015 February 10 (Extra) |
Hip, hip, hooray! Today Melody's doctor told her that her replacement hip is finally free of infection; no more surgery will be needed. The Battle of the Hips is finally over, and we won. Deo gratias. |
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2015 February 9 |
DSLR astrophotography notes How to take a DeepSkyStacker Autosave.tif file into PixInsight Manually color-balancing a picture in PixInsight or Photoshop Also, Nikon has released an astrophotography DSLR, the Nikon D810A. This is the first time anybody but Canon has released a DSLR for the astrophotography market. The camera has a full-frame sensor (24×36 mm, the same size as 35-mm film) and some nice features such as an exposure timer that goes all the way up to 15 minutes. But it's expensive ($3500?). What's really important is that this shows that DSLR astrophotography is here to stay. |
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2015 February 8 |
How to save money on a Sirius XM subscription Sirius XM just sent me my auto-renewal notice, and the price struck me as too high, so I called and said to cancel instead. Whereupon the price came down from $204 to $86 for the coming year. At that price, I was willing to renew. They are hoping, of course, that I will let them auto-renew next year for $204 or whatever the price has risen to at the time. I won't. I am uneasy about these widely differing prices for the same service to different customers (Proverbs 20:23). I prefer plain dealing. |
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2015 February 7 |
Comet Lovejoy retreats
Although it will be in the evening sky through March, Comet Lovejoy C/2014 Q2 is slightly past its prime. Here we see it next to the star Gamma Andromedae. The tail actually seems brighter than before, which is reasonable because dust and gas are still being emitted. Stack of three 30-second exposures, Canon 60Da on iOptron SkyTracker, Sigma 105/2.8 lens at f/4, ISO 1600. Orion is still there
The worst thing about having the flu was not being able to get out and do astrophotography. I'm still coughing, but I ventured outside briefly this evening to take the comet picture above and this picture of Orion (from M78 at the upper left corner to the Orion Nebula at the bottom). The purpose was to experiment with an Astronomik CLS filter, which cuts out the wavelengths of some common types streetlights. (As LED street lighting becomes common, this kind of filter will be much less effective, so I'm enjoying it while I can.) The filter gives the picture a blue-turquoise cast, but by adjusting the histograms in PixInsight such that R, G, and B peak together, I got a picture with natural color rendition. The filter helps greatly with pictures of nebulae like this. Unfortunately, it didn't help my view of the comet very much, so the comet picture above is one that was taken without it. Stack of five 30-second exposures, Sigma 105/2.8 lens at f/3.2 on a Canon 60Da at ISO 1600 with Astronomik CLS "clip-filter" on an iOptron SkyTracker. |
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2015 February 6 |
What killed Radio Shack Three things, I think:
America could have supported a chain of specialized stores for electronics hobbyists and people with technical needs. That's what Radio Shack was in the 1970s. But it's not what they've been trying to be since 1990 or so. |
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2015 February 5 |
Some perspective on the Anthem (Blue Cross) security breach A computer security breach at Anthem Blue Cross has led to unauthorized disclosure of customers' "names, birthdays, Social Security numbers, addresses and employment data including income." I'm probably one of the victims. While I regret that the breach happened, let's remember that this kind of information was not top secret in the first place. Admittedly, income has traditionally been confidential — unless you're a state employee as I was, in which case it's in public records. In recent years, everybody has decided to treat the Social Security Number as a secret password, but that's not what it was designed to be. It is just an identifying number. Likewise, birthdays, addresses, and employers have traditionally not been secret. My birth date is in at least two major reference books! I think the real problem here is that the banking industry has developed a strange concept of "identity" where anybody who knows some basic facts about me can impersonate me! In 1950 or 1970, that was not the case. And it's the banking industry's fault if they have made security depend on things that are not secure. Don't blame the victim, and don't burden the victim. The industry itself needs to take responsibility for developing more reliable ways to identify people. |
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2015 February 4 |
Here comes AoE 3 We may not have Radio Shack, but we still have AoE. The long-awaited third edition of Horowitz and Hill's The Art of Electronics is finally in production. This is a long-awaited event. The second edition came out in 1989; the first, in 1980. Finding the first edition in the Cal Tech bookstore in 1982 was a major turning point for me. At last, a book crammed full of things I actually wanted to know! As a newlywed, I couldn't afford it, but I managed to earn a copy by doing some reviewing for the publisher. Then I read it avidly until the next edition supplanted it. Horowitz and Hill were in the right place at the right time. The integrated-circuit (microchip) revolution happened just once, and I think practical electronics changed more between 1970 and 1980 than it has since! It's remarkable how up-to-date even the 1980 edition seems — while anything published even five years earlier is visibly antiquated. The other thing Horowitz and Hill did right was admit that working engineers don't spend their time solving differential equations. Almost all academic electronics textbooks were (and still are) about the mathematical beauty of circuit functions and how everything can be derived from Ohm's Law, Kirchhoff's Laws, and lots and lots of calculus. The thing is, once the basic circuits have been invented, we don't keep doing differential equations to figure out how they work. We use them as practical building blocks. And we don't need high-precision calculations of quantities that are not known to high precision. (The hfe of a transistor can range from 40 to 200, so despite their mathematical elegance, there's not a lot of point in doing the h-parameter calculations! Instead, you design a circuit so that the exact value doesn't matter. That is the essence of reliable circuit design.) Accordingly, The Art of Electronics is 1100 pages of how to make things work, and it hasn't gone out of date. Its only real predecessor is the famous Radiotron Designer's Handbook, from the vacuum-tube radio era. And its nearest competitor is a German book, Tietze et al.'s Halbleiter-Schaltungstechnik (which, however, is distinctly less "hands-on" than The Art of Electronics). |
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2015 February 3 (Extra) |
Requiem for Radio Shack I don't want to be premature, but all indications are that the Radio Shack chain of electronics stores will soon no longer be with us. During its heyday, the name was written as two words, not one. In the military (especially World War I) and in ham radio, a "radio shack" was any location for radio equipment, whether permanent or improvised. The Radio Shack was a store that opened in Boston in 1921 and, over the next several decades, opened a few branch locations. In the 1970s, Radio Shacks proliferated. I first set foot in one in Augusta, Georgia, in 1971. Until then, and for some time afterward, experimenters such as myself bought their parts and supplies either by mail-order — which was slow and awkward without the Internet — or from parts jobbers that supplied the radio and TV repair industry. These parts stores have almost vanished now; one of the last of a dying breed is Ack Electronics in Atlanta; but in their heyday, every town had at least one, and they looked and worked a lot like auto-parts stores. I relied on the one in Valdosta called Specialty Distributing Company. But by 1978 or so, every town had a Radio Shack. By the time Melody and I got to Los Angeles as newlyweds in 1982, Radio Shacks were ubiquitous. In several places I recall finding two or three that were in easy walking distance of each other. At that time I had just finished my Ph.D. in linguistics and was scrambling to acquire the computer and electronics knowledge that I would need for a computer-related career, and Radio Shack was an important source of knowledge and supplies. On one memorable visit to Santa Anita Mall, I bought a lot of discontinued digital ICs (which I used to teach myself combinational logic design) and Melody and I both discovered the music of Mannheim Steamroller. Over the years, Radio Shack has had its ups and downs. In the mid-1980s they had a problem with cheaply made, unreliable gadgets. Later, they tried to be a cell phone kiosk, then returned to their technological roots. Recently, they seemed to be doing well, selling power supply solutions (Radio Shack was where you could get a power supply for almost anything, with the appropriate coaxial connector) and also jumping on the Arduino bandwagon. I knew they were in financial difficulty but did not realize the end was imminent. |
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2015 February 2-3 |
Does Le Sueur mean what it looks like? Surely you've seen a brand of canned English peas called Le Sueur. The name puzzled me for some time, ever since I found out that sueur is French for 'sweat.' An odd thing to name a brand of canned peas. I guessed it was someone's surname and might be an alteration of Le Sieur, which is a minor title of nobility (compare monsieur). Not quite. I looked it up. Le Sueur peas are named for a county in Minnesota which is named for a French explorer. And his name, Le Sueur, has a different etymology. In earlier French, sueur could mean 'person who sews' (Latin sutor), not just 'sweat' (Latin sudor). It was an early surname for cobblers and tailors. Now you know! |
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2015 February 1 |
Is it wrong to work on Sunday? [Revised more than once.] If you thought this was a science blog, hang onto your hats — here's something completely different... One of the most confused points in Christian doctrine is the status of Sunday as a day of rest and worship. The following will probably interest my non-Christian readers as well as my fellow Christians, as I outline the main variations on the doctrine and something of the reasoning that leads to them. This is not a Bible study; I will not be reviewing all the relevant Scripture and theology and defending a position. I mainly want to present a menu of possible beliefs — to let you know what's out there. Some Christians don't realize that the Old Testament Sabbath (day of rest) was Saturday, the seventh day of the week. The Old Testament gives detailed laws forbidding work on the Sabbath and defining what constitutes work. Considering themselves exempt from Jewish ceremonial law, the early Christians switched to Sunday as their day of worship and rest, but only the beginning of this shift is recorded in the New Testament, which does not explain it in detail. A few Christians, such as Seventh-Day Adventists, have gone back to observing Saturday. Among the rest, you'll find the following four main positions: (1) Sunday is not the Old Testament Sabbath. It is our traditional day of worship but has no other special significance. (2) Sunday is not the Old Testament Sabbath but inherits some of its character as a day of worship and rest. No specific activities are forbidden on that day. (3) Sunday is the continuation of the Old Testament Sabbath and we must refrain from unnecessary work. (4) Sunday is the continuation of the Old Testament Sabbath and we must refrain as far as possible from work, secular entertainment, and non-religious personal activities. The first two are non-sabbatarian positions and the latter two are sabbatarian. Position (1) is not indefensible, but it is less than most Christians throughout history have believed, so I won't say a lot about it. Position (2) is written into The Baptist Faith and Message, as well as similar documents of many other Christian bodies, and is probably the most commonly held position across history. It is subtle. It maintains that the idea of a Sabbath is a merciful provision for human nature, but the law of the Sabbath was part of Old Testament and no longer applies to us. Slightly on the strict side of (2), as I understand it, is the traditional Roman Catholic position, which also appeals to many Protestants: Sunday is not the Sabbath; it is a newly established holy day that recurs weekly to honor the Resurrection. Catholics view Sunday as a day of obligatory worship and of "abstaining from unnecessary servile work." By "servile work" they mean the kind of work a servant or slave does — things that are tedious and/or tightly controlled by others. The idea is to give your servants the day off on a holy day, and to give yourself a day off from the same kind of work, as far as possible. Behind the notion of "servile work" is the recognition that not all "work" is tiresome; some of it can be restful and refreshing when done voluntarily for one's own satisfaction. This is something with which everyone can agree. Thus it's futile to try to make lists of what activities constitute "work" versus "rest." If it's something you feel like doing, and enjoy, then it's restful. In an era where most people don't get enough exercise, physical exertion isn't a good criterion. In one strand of Eastern Orthodox thought, there is a further subtlety: Saturday is still the Sabbath in honor of the end of Creation, but it is much less important than Christian holy days (including all Sundays) that no specific observance is prescribed. Now over to position (3), Sabbatarianism. The radical difference between (2) and (3) often goes unappreciated. The sabbatarian maintains that Sunday is not just like the Sabbath, it is the Sabbath. It's easy to adopt this position accidentally if you are a Christian trying to follow the Ten Commandments. It says to remember the Sabbath, and that must mean Sunday. Right? In fact, sabbatarianism is a minority position on the stage of Christian history. It is associated mainly with a movement in Calvinism — not Calvin himself, but later Calvinists, many of whom have gone all the way to position (4). They admit that sabbatarianism is not clearly taught in Scripture, but their position is that it follows logically from it, especially in a system of theology (covenant theology) that stresses continuity from the Old Testament to the New. Position (4) is written into the Westminster Confession of 1643, still used as a doctrinal statement by many Presbyterian churches:
And although I said I wasn't going to defend a position, I will say that in my opinion, position (4) is a mistake, and position (3) is probably the smaller mistake from which it arises. Position (4) imposes on Christians a restriction never found in the Bible. It seems, to me, entirely too much like people trying to win points with God by giving Him more than He asks for, as if He were too shy to ask for what we really need to give. Jesus repeatedly got criticized for healing people on the Sabbath (e.g., Mark 3:1-6). If people hadn't been wanting to deal with Him so brutally at the time, these situations would be funny: someone actually claimed it was more godly to refrain from work than to heal the sick. The notion that God is pleased by strict observance of man-made (or man-elaborated) rules is called legalism and is generally understood to be a serious mistake. And the same kind of small-minded people were afoot in the late 1800s, accusing their fellow Christians of "Sabbath-breaking" about trivialities. The ice cream sundae was supposedly invented to give soda fountains something to sell on Sundays when laws were passed against serving fizzy drinks on the "Sabbath." If that doesn't make you both laugh and wince, you may be the kind of person who would have hassled Jesus for healing people on the wrong days. So I will continue enjoying myself with writing, hobbies, exercise, etc., on Sundays with a clear conscience, while trying to avoid burdensome work. Finally, I'd like to tie up some loose ends. First, strict Sunday observance is particularly a part of rural American culture. I can think of two reasons. One is that if you're self-employed, nobody can give you a day off. If you're not forbidden to work, you must work. That gives farmers an incentive to treat Sunday as a day on which unnecessary work is strictly forbidden. Otherwise, they'd never get to stop working. The other is the long-standing American tradition of reading the Bible eagerly but without a lot of background knowledge. I'm in favor of people reading the Bible, of course. But it's tempting to read the clear, straightforward directives in the Old Testament and assume that they, or something very much like them, must apply to us; the theology of grace in books like Colossians is much harder to understand. Second, remember that the Ten Commandments are not a simple numbered list of ten. Much of the argument for Sabbatarianism is that we can't lose one of the Ten Commandments. In fact, however, the Ten Commandments are a brief summary of various moral and legal teachings that are expounded elsewhere. They are not numbered 1 to 10 in the Bible; there are several rival ways of numbering them, so that some people's Third Commandment is other people's Fourth Commandment. So the notion of a pristine set of ten things, all on the same level, is harder to defend than you might expect. Third, let's watch out for economics and politics disguised as piety. The main motive for "blue laws" (laws to require businesses to close on Sunday) is actually to keep big businesses from having an advantage over small ones. Super Mart can afford to operate all week long, but Mom and Pop's Hardware has no other employees, and Mom and Pop need a day off. You may believe that Mom and Pop's day off should be subsidized by restrictions on Super Mart, but when you argue this, please don't bring God's name into it. I am very uneasy with schemes to reduce people's freedom in the name of Christian piety with hidden economic motives. Of course, I applaud businesses such as Chick-Fil-A that choose to close on Sunday as an employee benefit, without trying to impose the same practice on others. |
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