Michael A. Covington    Michael A. Covington, Ph.D.
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Daily Notebook

Popular topics on this page:
A new verse for an old Christmas carol
Can't rename a folder on another computer
UPS falsely reports dead batteries after power failure
Against "cursive forever"
Sound card input levels revealed
Safely connecting pro audio gear to sound card
Fixing pinched optics in AT65EDQ (TS65)
Orion Nebula and Running Man Nebula
IC 405 (Flaming Star Nebula)
Zeta Orionis and Flame Nebula
Many more...
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Two thoughts about thinking and learning

(1) Making a simple thing complicated is a misuse of intelligence. We should be making complicated things simple.

But not simpler than they actually are, of course. People sometimes ask me to make something simpler than it can possibly be. (Like "Explain how a car works, but don't mention gasoline.") The most I can do for such a person is show them where to grab the complicated whole — that is, which parts are most important and need to be understood first.

(2) If you can't explain something simply, you don't understand it yourself.

That principle is credited to the great physicist Richard Feynman.

When you memorize and reproduce complicated sentences, words, or formulas without clearly understanding them yourself, you're not learning. You may think you are, but actually you are like the schoolchildren (described by Dewey, I think) who can recite "The sun rises in the east and sets in the west" but can't point to where the sun will set (and don't ask an intelligent question such as "Which way is west?"). To them, "east" and "west" are empty words. They think they know something, when all they're doing is reciting words they don't understand.

How many people's understanding of algebra, or science, or even bookkeeping is on this level? I have had an engineering student try to tell me, in all seriousness, that Ohm's Law doesn't describe how anything works, it's just a formula "that you can't understand." Sure, sure. To that kind of mind, "the sun sets in the west" is also just a formula you can't understand.


Zeta Orionis and the Flame Nebula

Still from the December 24 optics-testing session, here is an image of the Flame Nebula (to the left of the star Zeta Orionis) and, dimly, the Horsehead below it. This was taken from my driveway under somewhat hazy skies. It does help show which parts of the nebulosity are the brightest. It's a stack of ten 1-minute exposures, AT65EDQ, Nikon D5300 at ISO 400. For a much more generous exposure of the same field, click here.

Why I don't use Amazon Echo, Siri, or voice-recognizing toys

I don't think anyone has given enough thought to the security hazard of having a computer, always turned on, that is listening to your voice and is connected to the Internet.

Very simply, a bit of malicious programming could make it record everything it hears and send it to someone far away who might be up to no good.

Right now, there's a dispute about evidence in a murder case that may have been recorded by an Amazon Echo. Frankly, I trust the police more than I trust Amazon. We may be entering a bizarre world in which private companies claim the right to spy on us.

I distrust the "Internet of Things" as a whole (even though I have the technical skills and ought to be busy building it!). The Internet is inherently not very secure. Some parts of it, such as online banking, have been made secure by great effort. But cheap devices that are never updated are always going to be the least secure part.

I don't want my thermostat, car, etc., connected to the world-wide Internet so that someone might spy on them or even tamper with them from far away. Cheap children's toys that recognize voices, and use Wi-Fi, might be the biggest hazard.

For the Internet of Things to succeed, it's going to have to establish security standards and enforce them — and also not let manufacturers disclaim responsibility for what goes wrong. That may make an Internet thermostat cost $500 instead of $50. But it's what is really costs.

It may also make us rethink what we want from networking. The idea of the Internet is to put all the computers in the world on one network. That's great for mass communication, but not for privacy. Maybe the network within my house shouldn't have unrestricted access to and from the outside world.

Non-routable protocols such as Coraid's ATAoE might have a role; these are data packets that can travel on the network within one building but can't get through a router, and so can't escape into the outside world. Combine non-routable packets with one or two heavily secured computers that serve as gateways to the outer Internet, and you might have something.

2016 in review

This strange year, 2016, is going to last one second longer than a normal calendar year; there will be a leap second added to the end of it. How I'll spend the extra second, I don't know. Be ready for minor computer problems on computers that are scheduled to do something at midnight GMT (7 p.m. EST) and might do it twice.

On a more serious note, this year has been a wild mix of good and bad things. On the national level, we have elected an unusually inexperienced and controversial president, and during the campaign, some very ugly aspects of American politics were on display. But we have a strengthening economy.

And much has been made of the flurry of celebrity deaths (most recently Carrie Fisher and Debbie Reynolds). I think that what is actually happening is that 1960s and 1970s technology suddenly made it much easier to become very famous than before, and now we have a huge cohort of people who achieved fame then and are approaching the end of their lives now. (Also, we have very high-quality films and recordings of them, so they don't seem like people from the past; their movies and CDs don't look any older than recently-made ones.) From here on, celebrity deaths are going to be common because celebrities are a larger part of the aging population.

The media are also starting to point out that this generation of celebrities commonly lived much less healthy lifestyles than the general public, largely because of drug abuse, and that's why they're dying younger than their non-famous contemporaries.

On the personal and family level, we've had a mix of good and bad things. We have not yet met granddaughter Emily because Melody can't travel. (Surely by midsummer...) Sharon finally has a successful treatment for her painful damaged nerve; she isn't 100% recovered, but at least she's moving toward a normal life. (That, after life-threatening skirmishes with pneumonia and diabetes during the past year.) Melody lost the ability to walk in April, and it gradually became evident that her hip implant, treated for infection in 2014, was infected again; she is now at a convalescent facility getting further treatment and expects to have a permanent implant and be walking by April. We appreciate the best wishes and prayers of everyone who offered them.



On the evening of December 24 (yes, 24; remember, Christmas came for our family on the 18th), I took a few pictures to try out the newly repaired refractor. This is one. Stack of seven 1-minute exposures, AT65EDQ (6.5-cm f/6.5), Nikon D5300, ISO 400. What you see is the reflection nebula M78 in Orion and another nebula north of it.

The sky wasn't perfectly transparent, but it was unseasonably warm (55 F). We had a hot Christmas (74 F in mid-afternoon on the 25th).


How I fixed my AT65EDQ (TS65) refractor

A while back I noticed that my Astronomics AT65EDQ refractor (equivalent to Teleskop-Service TS65 (TS-APO65Q)) had an optical problem: the star images were crescent- or D-shaped. High magnification was needed to reveal the problem, which showed up most in the light spreading out around highly overexposed bright stars.

Curiously, the optical problem had gotten worse in the last few months. That's a strange thing for a defective lens to do! Here are "before" and "after" pictures, showing the problem on the left:

The problem turned out to be pinched optics, a common problem with this type of telescope. One of the retaining rings was too tight, and repeated thermal expansion and contraction made it get even tighter. It was compressing the lens. The lens mount is not as precisely shaped as the lens itself, and we don't want the lens to bend to follow slight irregularities in its metal mount. But it was doing so.

I loosened both retaining rings (having found the front one very tight) and left them only finger-tight. The procedure is described in this video. In brief:

  • Grasp the black part of the movable dewcap (sunshade) and unscrew the white part of it. Set that aside.
  • Now you can reach the front lens cell. Unscrew the ring with writing on it, revealing the retaining ring underneath.
  • You can loosen and gently retighten that retaining ring without further disassembly. You do not have to unscrew the front lens cell from the tube, but you can if you wish.
  • To get to the retaining ring for the rear element (field flattener), first unscrew the focuser from the (black) rear lens cell. Then unscrew the rear lens cell from the tube. The retaining ring to loosen and retighten is on the forward end of that cell.

Bear in mind that the optical test shown above is very sensitive because it was taken with a Nikon D5300, which has 3.9-micron pixels and no optical low-pass filter. You can see atmospheric irregularities and small imperfections in both images. But I think I made a difference!



Astronomy and the Star of Bethlehem

For those with questions about astronomy and the Star of Bethlehem, I refer you to what I wrote in 2004 with updates in 2007. Here are a few additional notes.

  • There are problems identifying, from historical records, the census that sent the Holy Family to Bethlehem in the first place. But as my friend Doug Downing and many others have pointed out, if the original text actually hadn't made sense, it would have been changed in ancient times by people who knew about the censuses in detail. This is true regardless of whether you believe in divine inspiration or even think the whole Gospel of Luke is fiction. So the confusion caused by the lack of surviving historical records is not a real problem.
  • Reliable sources tell me that exploratory trips by Persian sages (Magi) were common, so it was not unheard of for "wise men" to come to town and look around or ask questions. Admittedly they did not normally come looking for a new king! Herod must have thought that, whether they realized it or not, the Magi had discovered a plot to overthrow him.
  • We shouldn't think of Mary and Joseph in a barn behind an inn or of a possibly hostile innkeeper. The Gospel only says "lodging," which could be a public inn or a private home's guest room. No innkeeper is mentioned. In the architecture of the time, farm animals were kept in a room adjoining the house, not in a barn out back, which is why it would not be hard to get hold of a manger in or next to the house.

Let me wish you all a blessed Feast of the Nativity (Christmas), as well as giving you my best wishes for Hanukkah, the Winter Solstice, Sir Isaac Newton's birthday, New Year's Day, or whatever else you celebrate!


Progress report

Melody came through the operation fine, but because they implanted a temporary antibiotic-filled spacer rather than a regular hip implant, she has limited mobility and isn't ready to come home. She will strengthen and probably be able to join us at home before the next hip operation, but in the meantime, she will move from St. Mary's Hospital (shown below) to The Oaks, the same convalescent facility as two years ago. We want to thank at least 150 people (that we know of) for their prayers and best wishes.

We're having a quiet Christmas, but that's not a problem; Sharon and I are enjoying having a bit of time to ourselves. I've been so busy that I haven't gotten into my workshop or darkroom in a long time, and maybe I'll get to do so. And I have consulting work to do; I always do; as you might imagine, this month I got a bit behind schedule.




Melody's hip surgery, scheduled for December 21, has just been rescheduled for tomorrow (December 19). So we are eating dinner and are about to have family prayers, then celebrate Christmas hastily around a potted rosemary bush doing service as a tiny Christmas tree, then scramble to get ready to go to the hospital. (We will go around midday tomorrow but have a long list of things to do first, including two special baths.)

Prayers appreciated!


A prayer for people with hardened hearts

Recent events in our national life have turned friend against friend and brother against brother almost as if there had been a civil war. Many among us have become accustomed to feeling contempt for each other. For the fourth Sunday in Advent I want to share with you this prayer, which Melody composed, for people with hardened hearts, including, to the appropriate extent, ourselves.

Our Heavenly Father,

We pray for those with hardened hearts,
who no longer hear words of truth,
who live with unfocused anger,
and sometimes raise their hands in violence
against their fellow man.

Grant that their hearts may be softened,
theirs ears opened to reason,
and their minds unclouded from hatred.

Teach them to love again,
and hold all your children in loving esteem,
seeing no difference in the color of their skin,
or the language they speak,
or the country they came from,
or whether their bodies are broken.

Guide them with your boundless love,
to love others as they love themselves.
Grant that those with hardened hearts
find themselves convicted of their sins,
repent of those sins,
and be brought ever closer to you.

Let those with hardened hearts be stricken by your Holy Spirit,
to become as our Lord Jesus Christ,
giving of themselves when there is a need,
caring for those without necessities,
speaking as Christ's wisdom guides us,
always speaking gently and kindly to others.

We praise your Holy Name. Honor and Glory Forever!

More 3D drafting

In just one day I've graduated from Microsoft 3D Designer to Autodesk 123D, which is free for noncommercial use and cheap (by subscription) for commercial use.

It produces solid models, not just mesh models; allows rotation about the center of any face of any object, making it easy for me to simulate the movements of a telescope mount; and will do orthographic projection (infinite-distance perspective). Also, it has a "screen shot" function that outputs a 2D bitmap image of what is on the screen, without the grid.


A strange misconception about my work

I recently learned about a mistaken impression that some of my friends, relatives, and neighbors must have had during much of my career.

Some people think that when a professor gets a research grant, the money goes to the professor. So if I bring in a few million dollars for research, I'm rich.

To quote the old lady in the TV commercial, "That's not how any of this works!" Grant money goes into the university's budget. About a third of it goes for overhead (buildings, offices, secretarial support); the rest goes mostly for graduate assistantships (that's how we pay for people to go to graduate school) and for special equipment and travel. In some sciences, of course, equipment is the major cost.

The only way a grant can help me financially is (1) by keeping me employed in the first place (some research jobs depend on bringing in grant money), and (2) by allowing me to be employed 12 months out of the year instead of the normal 9 or 10. There is a rule that grants cannot be used to fund pay raises.

3-dimensional drafting

I've made my first foray into 3-dimensional drafting. Although the main reason people do this is to make things with 3D printers, my need was completely different. I need to make some accurate line drawings of a telescope on an equatorial mount aimed in various directions, and I wanted the computer to figure out the perspective for me.

In the picture, there's no tripod beneath the telescope. That's intentional. I want to dispel the myth that "you have to level the tripod." False. As long as the polar axis (the orange part) points in the right direction, it doesn't care what's under it. The tripod is just to hold it up. The only reason the tripod has a bubble level on it is to help you set it up in the same position as the previous night.

I tried Microsoft 3D Builder (free with Windows 10), Sketchup, and Blender and settled on the first one. It's freeware and very easy to use. Sketchup is relatively easy to use but not free for commercial use, and they probably consider my use commercial. Blender is elaborate, powerful, and mystifying to the beginner.

The best thing about the Microsoft 3D Builder user interface is that it makes easy things easy. That is much more important than making hard things easy. If the simplest operations are not quick and obvious, the software will always be tedious. This one got it right.

Because it's not mechanical engineering software, 3D Builder does not let me rotate any part around an arbitrary axis, so it took some thought to get everything rotated all the ways I wanted, without disrupting anything else. But I did it. I can capture 2D images as PDF and then either edge-find them with Photoshop or trace them in Illustrator.



Here you see a CEREC numerically controlled milling machine making a crown for my tooth, the one that underwent a root canal 30 days ago. During the installation of the crown, to add dignity to the occasion, we listened to Händel's Coronation Anthems.


  • I had been harboring an abscessed tooth for about 4 months, with minimal symptoms. It was wearing down my overall health just a bit.
  • A root canal doesn't hurt. What hurts is needing one and not having it.
  • Crowning a tooth that has had a root canal did not require any anesthesia and did not cause any pain.
  • With CEREC, the whole procedure was about 2.5 hours from beginning to end. There were two intermissions (when the crown was being made and when it was being baked), and I caught up on e-mail.

Hoax (?) the day: Do they have to say ze at Oxford?


The strange news story today is that some substantial part of Oxford University has ordered people to say ze as a gender-neutral pronoun in place of he or she.

Major newspapers seem to have been taken in, but it defies confirmation. See this. At the very least, if a pamphlet was given out, someone should be able to find a copy of it.

This may be an inaccurate report of something real but misunderstood, or it may be a prank.

Short notes

Melody's next hip operation (to deal with an infection in the same artificial joint that got infected in 2014) is December 21, so Christmas will come early for us, on December 20, and will be low-key.

Refrigiwear is highly recommended. I am in the process of getting a cold-weather coverall for astronomy. Their products are well made and are much warmer than hunting coveralls. I tried one on and am sending it back for a different size; I may end up with a custom-altered one (which they offer).

They say to allow an additional 20 to 25 F for sedentary work (astronomy) compared to ordinary outdoor labor. So I'm ordering a suit rated for -50 to +20 F, expecting to use it to about +45 F during our southern winters. A hunting coverall is comfortable at +50 F but not much lower.

Part of this is that I'm cold-natured, and part of it is that I like to wear the coverall over regular clothes, without adding more layers, so I can get in and out of it quickly. That's just me; I don't like to make getting dressed into an elaborate ritual.


A new (old) verse for an old Christmas carol

If I contribute anything to the world's stock of Christmas music, it will be the following, which can be sung as an additional verse of "Child in the Manger" either before or after the existing verses, or substituted for the first verse. (The tune is "Morning Has Broken.")

God above Heaven,
born of a virgin,
God beyond space, now
sheltered on Earth:
This day is holy!
Sing to the Saviour;
shepherds and angels
herald His birth.

This is my translation of the opening of the Nativity canticle of St. Romanos Melodos, "Today the Virgin gives birth to the one above all existence (epiousion)..."

For several years I thought about trying to translate more of the canticle to make more verses, but I got stuck. I think this one works well substituted or appended into the existing song.

To all my readers: Feel free to sing this. If you publish it or record it commercially, I would like to hear from you. Like all of the Daily Notebook, it is covered by copyright, so you are using it with my permission.

Safely connecting pro audio equipment to a computer sound card

In yesterday's exciting episode (see below) we learned that professional audio equipment can damage a computer sound card because pro "line level" goes as high as 4 V rms, but the most a sound card can handle without damage may be as little as 2.8 V rms. I've encountered a case where this seems to have happened.

Of course, you can use a professional sound card designed to interface to professional equipment — or you can do what I did.

I built this gadget, hiding the resistors inside the inline phone jack. It accomplishes two things: it cuts the voltage to an acceptable level, and it ensures that the ring (R) on the sound card is not connected to anything, since computer microphones use R for power, not for signal.

For more about sound card input levels, scroll down.


Sound card input levels revealed

What are the correct audio signal levels (in volts or millivolts) for a computer sound card? That information is very hard to come by; a long web search found me little beyond vague statements. So I decided to make my own measurements.

Surprise #1: Line and Mic may refer to the same levels! In the normal audio world, Line is about 0.5 V rms (in consumer equipment) or about 3 V rms (in pro equipment), and microphones output about 2 mV rms.

Not in the world of sound cards! Computer microphones have small preamplifiers built in. In fact, sound card inputs, both mic and line, are in between the mic and line levels used by other equipment. The most generally suitable signal level, at either type of input, is about 0.2 V rms, but the gain controls span a wide range.

Surprise #2: Pro audio equipment can damage a computer sound card! That's right — pro audio "line level" can deliver as much as 10 volts peak-to-peak, 3 or 4 volts rms, and that exceeds the maximum ratings for the chips in sound cards. I consulted an older Cmedia CM108 data sheet and found and absolute maximum rating of 2.8 V peak-to-peak, equivalent to 1 V rms at the mic or line input. Go much beyond that, and the chip can be harmed. Go beyond 5 V peak-to-peak, and it certainly will.

Surprise #3: The lowest gain settings are essentially not meant to be used. Aim to have the gain controls somewhere around 50 to 75 on a scale of 100. To get a full-scale signal at a gain of 10 (on a scale of 100), I would have to apply voltages higher than the electrical specifications allow.

Recall that the difference between mic and line inputs is largely wiring, though the mic input may also have a wider range of gain or an optional 20-dB boost. The mic input is monophonic and uses the ring of the connector for a 5-volt power supply through a 4700-ohm resistor (or thereabouts). The line input is stereo.

Now for the actual measurements. These are the level of a 1-kHz sine wave that produces a level shown as 7 out of 8 bars in Windows Control Panel with various settings of the level control. These are rms voltages; peak-to-peak voltages are 2.8 times as much.

Equipment Gain = 50 Gain = 100
Cmedia USB soundcard, mic input 0.6 V rms 0.09 V rms
Cmedia USB soundcard, line input 0.6 V rms 0.09 V rms
Realtek motherboard audio, mic input, no boost 0.8 V rms 0.06 V rms
Realtek motherboard audio, mic input, 20 dB boost  0.08 V rms  0.006 V rms
Realtek motherboard audio, line input 0.8 V rms 0.18 V rms

Now you know!


IC 405 in blue

This, too, was meant just as an autoguider test (on December 1), but it came out fairly good for a picture taken in town. This is the emission and reflection nebula IC 405 around the star AE Aurigae, which appears to have been violently ejected from the Orion Nebula many, many years ago. The nebula that presently surrounds it is unrelated; the star is just passing through. Stack of four 5-minute exposures, AT65EDQ, Nikon D5300.

Out with the old, in with the ... same

The screen of my iPhone 5 was deteriorating, and through their insurance program AT&T gave me a very cheap upgrade to an iPhone SE, which is a more modern phone built into the same case. New, but nothing different, and that's how I like it.

After five years of heavy use, my Casio WV-58A wristwatch (which sets itself automatically from longwave radio time signals) was deteriorating too, and I got a new watch just like it (well, with a darker-toned enclosure) from Amazon for under $25. I then transplanted the watch band onto it (the band may be worth more than the watch). Again, new, but nothing different. It does look spiffier, though!


Against "cursive forever"

Strong rants are being circulated on Facebook making the claim that if our elementary schools stop teaching cursive handwriting, civilization will collapse, or something equally dire will happen.

I disagree.

I believe that it is very important for people to learn to write neatly with a pen. In fact, learning to write goes hand-in-hand with learning to read.

But Palmer Method Cursive is not the right way to do it. Palmer Cursive has had a stranglehold on American education for about a century, and it's time for it to go.

Cursive handwriting was designed for 18th-century dip pens that shouldn't be lifted off the paper. Modern pens don't have that quirk.

My objections to Palmer Cursive and its derivatives (Zaner-Bloser, etc.) are:

  • It makes the children learn two alphabets. Some of the letters look quite different in cursive than in print.
  • It's hard to read. Palmer's system, especially, makes different letters look too much alike. Even the best cursive is hard to read. Done sloppily, it's impossible to read, as all of us know.
  • It takes way too much time for people to learn it and build skill, time that could be spend on other things (including learning to handwrite more clearly with a different system!).

I'm not against handwriting. I think everyone needs to learn to print clearly and to write quickly and legibly in a flowing way, but that doesn't mean cursive. I prefer Fairbank italic, which is what I normally use (a bit sped up and simplified). My italic is as fast as anyone's cursive, can be written with any kind of pen (although an italic pen makes it look prettier), and is much easier to read.

I also think the D'Nealian system, now popular in elementary schools, was a step in the right direction. It is based on the notion that children should not have to learn two alphabets — that there is a smooth transition from the separate to the connected way of writing. But its goal is to end up with something that looks too much like Palmer Cursive for my taste.

What I want to do now is answer some of the arguments I hear for cursive, some of which are sillier than others.

(1) "Printing (writing separate letters) is too slow and too tiring."

Granted, it is if you're not doing it right. It's important to have a fixed, smoothly flowing set of muscle movements associated with each letter.

It's also important not to use a ballpoint pen that requires ten pounds of pressure! To keep from getting tired, write with a rollerball or fountain pen.

(2) "Cursive is traditional and everybody needs to know how to read it."

Yes, but you can learn to read cursive in a few hours in art class in fifth grade, rather than taking countless classroom hours for several years. They started teaching me cursive in second grade and didn't stop until seventh!

(3) "People need to know cursive so they can read the Declaration of Independence."

See previous point, to which I would add two more:

(a) Can you tell me the rules for using the long and short lowercase S in the cursive writing of 1776? If not, maybe you don't know enough cursive for the Declaration of Independence either.

(b) Why stop at the Declaration of Independence? Can you read the Magna Carta? It's in Latin and in a kind of cursive that even you would find daunting.

(4) "How will people sign checks?"

Again, learning to sign your own name is not something that will take years; in today's society it's more an art project that part of your literacy. And the real answer is that people don't sign checks much any more. They use computer authentication of various kinds.

(5) "It fills up the time and gives the less intelligent students something to be good at."

This is being offered as a serious argument. Basically, it's a way to take up time and offer less education and less intellectual challenge. Are you sure that's what you want to ask for?

And if you do need some easy material to fill up the time, could it be something more useful than penmanship?

Like teaching them to type?

They're not going to go work as scriveners for Ebenezer Scrooge and "copy out the letters in a big round hand." Since the 1930s, office workers have had typewriters. Today it's computers.

Afterthought: If the schools in the 1960s had been up to date, they would have taught us to type in fourth grade. Instead, they drilled us on Palmer Cursive for years as if we were going to be office workers in 1890.

(6) "I had to do it, and I want things to be just like my own childhood."

Well, things are not going to be like your own childhood. Your children are never going to live in a world without computers, smartphones, and electronic funds transfers. You can't go back. Don't ask children to be prepared for life in 1950 or 1890. That's not where they're going to live.


M42 and the Running Man

This is a stack of three 5-minute exposures of the Orion Nebula region, taken with an AT65EDQ (65-mm f/6.5) and Nikon D5300 on an AVX mount, testing a 60-mm guidescope, which passed the test with flying colors.

I shall name this guidescope Goldilocks because it is not too big and not too small. My previous 80-mm guidescope is somewhat prone to flexure because of its great size and because its focuser wasn't specifically designed for guiding. My tiny homemade 35-mm guidescope is rigid but has poor optical quality, possibly a collimation problem that I can improve.

I want to call your attention to the smaller nebula at the top of the picture, NGC 1973-1975-1977. In front of it is a dark nebula that looks like a man running very fast. It is called the Running Man Nebula.

The nebula has three NGC numbers because it was discovered visually, with telescopes, and was seen as disconnected bright spots; the connection between them was not visible. And they are an auspicious set of NGC numbers; I entered the University of Georgia in 1973, met Melody in 1975, and graduated in 1977. Next I need to look for NGC 1982, our wedding date!

[Addendum:] It turns out NGC 1982 is in the picture too. It is the upper part of the nebula in the middle; a dark rift separates it from the main part. NGC 1982 is better known as M43.

Quote for the day

"Fallacies are more easily nipped in the flower than in the bud."

Thus said Augustus de Morgan in his book about crackpots, A Budget of Paradoxes. What he meant is that a mistake often needs to be taken to its logical conclusion so that people can see that it's a mistake.


UPS falsely reports defective batteries after a power failure

APS XS-1200 uninterruptible power supply (but this probably applies to many, many others too). Symptom: After running down its batteries during a power failure, the UPS tries to recharge its batteries, and fails, so that a day or two later, it reports defective batteries. (This particular one was so foolish as to actually shut down, turning off the computer and router, even though normal AC power was coming in.)

In many cases, of course, an aging lead-acid battery does die when completely discharged.

But that wasn't what happened to mine. I took the two batteries out and experimented with charging them. It was quickly evident that they would take a charge normally.

So I charged them (using a lab power supply, but a trickle charger would be better) for several hours, then put them back in the UPS (with no computer attached), plugged it into the AC line, and turned it on.

The batteries charged all the way back up to full charge in another two days, and then they passed the self-test.


Windows won't let you rename a folder on another computer

Symptom: You've just created a folder (as "New Folder") within a folder shared by another computer. You try to rename it, and Windows seems to hang. After a very long time, the renaming succeeds.

Explanation: The Windows Search service has grabbed the new folder and is trying to index it. While the Windows Search service holds it open, no one else can rename or delete it.

Cure: The simplest is to disable the Windows Search service on the computer that holds the files. Control Panel, Administrative Tools, Services, find the Windows Search service, stop it, and set it to Disabled.

Alternatively, it may be sufficient to disable indexing on one folder through its Properties window. I haven't tried this.

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