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

Popular topics on this page:
Microsoft fixes Windows 10 webcam problem
Beware of the worst kind of gossip
Beware of losing the big picture
Lowell and the spokes of Venus
Gould's Belt
Should every teenager flip burgers?
What to do if cyberwar breaks out

Field of Mu Cephei
Field of Delta Aquilae
Field of Zeta Aquilae
Field of Gamma Cygni (Sadr)
Pipe Nebula
Gamma Sagittarii star cloud
M52 and Bubble Nebula (NGC 7635)
Field of M24
Field of M24
Many more...
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The heart of Cygnus and a little-known nebula

The first deep-sky observing I ever did, back in October of 1967, consisted of going out with binoculars at my grandparents' house and looking at the Milky Way. I did not know any constellations, but I did have a sky map and knew roughly what part of the sky to look at. What I saw was the Milky Way in Cygnus, high overhead, and it was dazzling. I didn't actually learn any constellations or look at the sky very much more until the Belt of Orion caught my eye in March 1968.

Since then, I've kept coming back to the middle of Cygnus. That's what you see above, and specifically, the field of Gamma Cygni (Sadr), surrounded by nebulae light and dark. This is a stack of 30 (yes, 30) 1-minute exposures with a Nikon D5300 at ISO 400 and 180-mm ED AI lens at f/2.8. It was taken in town, so the view is not as good as if I had been at Deerlick, but it is still spectacular.

I want to call your attention to the blurry star in the lower left corner. It is 44 Cygni, surrounded by a reflection nebula, which you can see if you click on the link to Simbad.

Curiously, this nebula is almost unknown to science. It is designated GN.20.29.1 in Neckel and Vehrenberg's Atlas of Galactic Nebulae. Simbad returns only one bibliography entry for it, Magakian's Merged Catalogue of Reflection Nebulae.

[Updated twice:] It's not so unknown after all. It's van den Bergh 133, and I didn't realize that when Simbad lists a reflection nebula involving just one star, they equate it with the star itself. Thanks to someone on Cloudy Nights Astronomy Forum whose name I didn't catch, I can offer you this link for an excellent picture and more information.

44 Cygni is a close double star and is not variable, so there is no reason to expect this to be a variable nebula. It must have gone largely unnoticed mainly because there are so many other fine sights nearby.


Another view of M24

The star cloud M24, which dominates yesterday's picture (below), is seen here at greater magnification. This picture was taken in town, so it doesn't have as much contrast, but I was able to subtract out the city lights to a remarkable degree. Stack of thirteen 1-minute exposures, Nikon D5300, ISO 400, Nikon ED AI 180/2.8 lens at f/4.


The heart of the Milky Way

Click for higher-resolution image

Saving the best for last, here is my pièce de résistance from the September 30 trip to Deerlick. You're looking at the star cloud M24, with the Swan and Eagle Nebulae above it, along with streaks of interstellar dust.

Stack of fourteen 1-minute exposures, Canon 60Da, 105-mm f/2.8 lens, ISO 1600, iOptron SkyTracker.

How I doubled the sensitivity of my Canon 60Da

Soon after getting my Canon 60Da four years ago, I made the mistake of choosing "Highlight Tone Priority" on the menu, to avoid overexposing highlights in daytime pictures. I thought it only affected the exposure meter.

Just now I've been testing the sensor quantitatively, and I discovered to my dismay that "Highlight Tone Priority" cuts the analog gain (DN/e-) in half. It's equivalent to cutting the ISO setting in half.

So almost all my serious photography with the 60Da has been done at half the ISO speed that I intended. No wonder I got good results at 3200 a while back; it was really 1600. The picture above was taken with the camera set to 1600 but really operating at 800, which is less than optimal.

I've turned Highlight Tone Priority off!


What to do if cyberwar breaks out

Today (Oct. 21) there have been at least two large denial-of-service attacks on the Internet in the eastern United States. I have no way to know who is behind them, but attacks of this type have some risk of being "state-sponsored," meaning a hostile country or rebel force is behind them. I have no information about the source of today's attacks, but they were carried out on a surprisingly large scale.

Note that today we have not had "hackers" trying to break into accounts or steal personal information. We've had an attack on the ability to communicate, achieved by flooding web servers and address servers with requests for information. This doesn't enable criminals to steal anything. Its only purpose is to disrupt. It is the kind of thing hostile countries plan to do to each other in wartime.

Supposing "cyberwar" breaks out, how can you protect yourself? Here's my advice.

(1) Do not expect the Internet to be perfectly reliable. Conduct your life so that you won't be harmed by outages. Keep paper copies of essential records.

(2) Do not obey instructions that you receive unexpectedly, no matter who they claim to come from. The bad guys want to infect your computer with a virus. Nowadays, almost all viruses require the permission of the victim to install them. So who installs them? People who do anything the words on the screen say! There are entirely too many such people. Don't be one of them.

Fake software updates are a possibility, so if the situation continues to warrant suspicion, this might be a good time to put off updates. On the other hand, you may be offered legitimate updates that are protective. Ask knowledgeable people and find out what you can.

(3) This is not a good time to play with free software whose source you're not sure of. It may be virus-infected. Even if it was perfectly good to begin with, it may have had a virus added by someone else. Don't be paranoid, but do run checks.

(4) Do not open files that arrive attached to e-mail unless you're sure they're genuine. I've had a flurry of fake "invoices" and "bills" and "payments" from strangers that were really virus installers (none of which I opened).

(5) Beware of fake news and fake web sites. Disrupting the DNS system could be a preparation for setting up a fake CNN.com, fake BBC.co.uk, fake Fox News, etc., and directing people to the fake web site in place of the real one. It would contain mostly a copy of the real site, but with slight alterations. It is much harder to fake sites that require a password to log in (such as Facebook), but if a web site asks you for a password when you thought you were already logged in, it may be fake. Keep your eyes open.

(6) Beware of gossip. The easiest way to circulate fake news is of course just to make a "meme" or a "pass this on" message and put it on Facebook. Too many people will pass along anything they're told to!


Should every teenager flip burgers?

Should every teenager have a menial entry-level job as part of the process of growing up?

I discussed this with a group of friends recently, including some distinguished educators, and here's what we concluded.

(1) If the family needs the money, or it helps the teenager go to college, then go for it. It is very fulfilling to help your family or fund your own education.

(2) On the other hand, if the money isn't needed and the job doesn't build important skills, not so fast. A job, providing pocket money to someone with no clear plans or needs, can be a path away from success. Smoking, drinking, and drugs require pocket money that parents can't track, and that's what a job provides. Then there are the opportunities provided by a self-funded, parents-not-involved automobile...

On a more mundane level, people learn bad attitudes from jobs. If they learn that they're supposed to hate their job and whine about it, that's a real career-killer. And if their co-workers are people who are aiming low, they may start aiming low too.

So there is a lot to be said for letting young people spend their time getting education, skills, and even enjoyment from a wide variety of things, rather than being put to work just because it's possible.

But there are some important things people learn from their first job. Among them:

(1) You can do menial work that you thought was beneath your dignity, and there is satisfaction in doing it because people need it. Cleaning toilets, for instance, is no one's hobby, but is worth doing.

(2) In real life, 70% isn't passing. If people tell you something needs doing, then it really does — completely and accurately — or else they're bluffing, which is rarely the case.

(3) You have to meet other people's needs, providing services to other people. That is the essence of business.

It may not actually take very long to learn these things, and they can be learned in settings other than an entry-level job. For me, it was a travel club called The Action Trav'lers, although (2) and (3) were mostly intuitive already.

What puzzles me is the notion that, as a coming-of-age ritual, teenagers need menial jobs even if they have specialized skills. I never flipped burgers; if I had had to work at 15, I would have done photography. (Before I was 17 I got into computer programming and had a part-time job doing it.) Plenty of people who are doing well in high school are literate enough to do secretarial work. Others have other capabilities. Shouldn't we be teaching people to use what they have?

The conversation was on line, and I don't remember all the participants, or exactly what each one contributed. I especially want to thank three seasoned educators, Paula Schwanenflugel, Sarah Tillery Caldwell, and Lew Nix.


Moon and Aldebaran

Around 1:20 this morning, the star Aldebaran disappeared behind the edge of the Moon (as seen from here) and was hidden for about three quarters of an hour. Clouds kept me from seeing the actual disappearance, but here is a picture taken a few minutes beforehand. Celestron 5 (vintage 1980), Canon 60Da, single 1/400-second exposure at ISO 800, postprocessed with Photoshop.


Gould's Belt


An astronomical fact I've been contemplating lately is that a lot of bright stars seen from Earth are not on the Milky Way, but rather west of it (that is, to the right of it, seen from the Northern Hemisphere). The bright constellations Orion and Scorpius are conspicuous examples.

In fact, there is a band of bright stars, encircling the entire sky, inclined at an angle to the Milky Way.

It's known as Gould's Belt and was reported in 1879. And it's real — a flattish cloud of nearby stars, not quite parallel to the galactic plane, about 3000 light-years in diameter. We're near the center of it, but the actual center is thought to be in the direction of Perseus.

Gould's Belt crosses the Milky Way in Cepheus. From there it heads south through Perseus, Orion, Canis Major, Puppis, and Carina (all west of the Milky Way). It crosses the Milky Way again in Vela, Crux, and Centaurus, then comes north (again west of the Milky Way) through Scorpius and thins out a bit; in Ophiuchus it is not as conspicuous as elsewhere. From there, through Lyra and Cepheus, it completes the loop.

Benjamin Gould described the belt on pages 354-357 of the Uranometria Argentina, his catalogue of stars visible from the Southern Hemisphere; it came up as he was doing statistical checks to make sure his measurements of star brightness were compatible with other catalogues. But he says he had previously mentioned it in the Proceedings of the American Association for the Advancement of Science, 1874, p. 115, a reference I have not yet been able to follow up.

Since it is a physically real and significant part of our galaxy, Gould's Belt is being explored by researchers.



The Mercedes logo in Percival Lowell's eye

Today has been my first "sick day" in years, in the sense that I didn't even get out of pajamas. I had a sudden gastrointestinal problem but am much better now — still taking it easy in order to be up and at 'em tomorrow. During the day I've done some interesting reading. Here is a spinoff from some of it...

Notoriously, the astronomer Percival Lowell (of the "canals of Mars") saw radial streaks or spokes on Venus that nobody else except his loyal secretary could see. Here is his map, which looks utterly unlike any other astronomer's picture of Venus:

Believed to be in the public domain; obtained from www.phenomena.org.uk.

To observe Venus, Lowell used his great telescope at 140×, but stopped down to an aperture of just 1.5 to 3 inches — which made it smaller than most amateur telescopes — giving an extremely small exit pupil. In effect, his retina was being lit by a point source, or nearly so.

In that situation, optical defects in the observer's eye are strongly visible on top of the image.

[Update:] Lowell himself discovered that this was an optical effect in his eye, though he was at a loss to explain it. I haven't read his whole article yet. (Astronomische Nachrichten 160:129-132, 1902.)

One standard explanation of Lowell's "spokes," from William Sheehan and Thomas Dobbins, is that Lowell was seeing the blood vessels in his own eye. (Article here.) You've probably seen yours, at the eye doctor, when your whole retina is suddenly illuminated by a point source of light. You see a dark spot with slightly irregular spokes (vessels) radiating out of it.

I've always been uneasy with that explanation because the vessels cover the whole retina. You would not see them projected onto the small image of a planet. At 140× in a telescope, Venus looks about as big as the moon seen with the unaided eye. It does not cover much of the field of view.

In Galactic Encounters, which I'm reading now, Sheehan tosses out another possibility — Lowell may have had a congenital cataract, or rather what is known as a Y-suture cataract (they can also arise during adulthood).

I read up on this, and it seems to fit. During fetal growth, the lens of the eye grows in three sections (like a Mercedes-Benz logo), which join together. A common abnormality is for the junction lines (the "Y sutures") not to be completely clear. (Excellent picture here.) As I understand it, there are two Y sutures, on the front and back of the lens, one of them upside down relative to the other. In the adult eye, each of them can have more than three branches.

Y-suture cataracts usually "not visually significant" — they do not affect vision in everyday life.

But if anything would make them visible, it would be using a telescope with a tiny exit pupil. The pupil of the eye closes down to about 2 mm, or a little smaller, in bright light. A telescope at high power, however, sends out a beam of light much smaller than this. I don't go below 1 mm with my own telescope, but as we noted, Lowell went down to about 0.3 mm. That would bring out the worst in any eye, and in fact would make it easy to see tiny irregularities that are not normally considered optical problems at all.

The crucial difference between Y-suture cataracts and blood vessels on the retina is that the visible part of the Y suture can be very small, less than 1 mm in diameter, and hence easily seen projected onto the image in a telescope — and not seen in any other situation.

I haven't entirely worked out the optics, but I think this theory needs to remain on the table. Lowell's map of Venus, after all, looks very much like two Mercedes logos, right side up and upside down, superimposed on each other, just what you'd expect from Y sutures on the front and back of the lens.


Beware of the worst kind of gossip

The most evil and destructive kind of gossip is the kind that doesn't even make any claims of fact — just "something awful is about to be revealed" or "they're terrible, but I can't give you any details."

Because it can't be fact-checked, that kind of gossip is pure manipulation. You're being asked to side against someone without even being given a reason.

At least one such piece of gossip, about a political candidate, is being trumpeted loudly by an online commentator this morning. There's going to be plenty more.

I call upon everyone with a conscience to disregard that kind of gossip (no matter which side it's on) and shun those who originate and spread it.

Admittedly, unconfirmed misconduct by a candidate or public official may be of public interest. But all allegations should be made in a way that leads toward fair determination of the facts. Say what they're supposed to have done and what the evidence is.

"Thou shalt not bear false witness" has not been repealed.

Beware of losing the big picture

As a political train wreck continues to unfold (do train wrecks unfold? hmmm...) in America, I stand by everything I said about the voter's dilemma three months ago, and I also want to add a really big caution:

Don't lose sight of the big picture.

This close to the election, a lot of people's strategy is to make you focus on one fact or allegation that's supposed to make up your mind for you.

That means forgetting everything else you know.

And forgetting relevant knowledge is not good.

In particular, don't forget that you are voting for a candidate, not a platform, and you have a duty to use all your knowledge of what is likely actually to happen when that candidate is elected. It's not enough to wash your hands of reality and high-mindedly vote for a platform. A platform will not take office.

His name was Saint-Saëns

Trivia: The composer Camille Saint-Saëns was also an amateur astronomer and wrote magazine articles about astronomy. Many of them are on line here.

There has been a 200-year controversy about how to pronounce his name. Saint-Saën(s) is the name of a village that changed the pronunciation of its name at least twice.

The final -s is pronounced (nowadays) although there was a time when it wasn't, and I'm not not sure whether the man himself pronounced it. The ë is silent even though two dots over a vowel in a Romance language normally mark it as not silent. So Saëns is pronounced as if it were spelled Sance — it rhymes with France (in French, not English).

The music is great, whichever way you pronounce the name. Listen to some.


The field of Mu Cephei and a meteor

Here is the region of Mu Cephei (the Garnet Star) and a large emission nebula (at the lower right) with streaks of dark nebula running in front of it, making it look broken. Again, we are looking at a relatively nearby part of our galaxy, in the plane of our galaxy but not close to the direction of the galactic center.

Stack of 25 one-minute exposures with a Canon 60Da at ISO 1600 and a Sigma 105-mm f/2.8 lens on an iOptron SkyTracker, at the Peach State Star Gaze on September 30.

Now for a surprise. While reviewing the images in the camera I noticed that one of them had caught a telescopic meteor (near the top of this enlarged image):

I say "telescopic meteor" because its path is so short, something like a quarter of a degree, indicating that it was a tiny particle that burned up high in the atmosphere. We do see meteors through telescopes occasionally, and this is one that could have been seen that way. It must have been quite bright, since it was exposed for much less than a second, moving all the time, and the rest of the picture was exposed for 60 seconds, tracking the stars.

Why doesn't it show up in the combined image above? Because the image-stacking algorithm rejects pixels whose values disagree too strongly with the average of all the other images. That effectively eliminates airplanes and satellites, but also meteors.


Star clouds around Delta Aquilae

Still more astrophotography from the Peach State Star Gaze. Here you see star clouds around Delta Aquilae, a little farther from the galactic center than the Sagittarius pictures that I posted earlier. Stack of 25 1-minute exposures with a Canon 60Da, 105-mm f/2.8 lens, and iOptron SkyTracker. Notice the "river" or streak of interstellar dust below the center of the picture.


Short notes

Short notes on more cheerful subjects today...

His name was Abbe, not Abbé. I'm referring to the noted German optician who invented the orthoscopic eyepiece and also gave us the Abbe number for chromatic dispersion. Much earlier in history, his surname was apparently the French name Abbé, but not in his own time. He wrote it Abbe and pronounced it (roughly) "AH-buh," not "ah-BAY." Click here to hear me pronounce it, or look at this German documentary.

Noto fonts recommended, with one caveat. Google has released, as freeware, a set of TrueType fonts that aim to cover all of Unicode so you won't get "tofu" (white rectangles) when you display foreign languages. I recommend downloading and installing them. They are intended to be used under all operating systems.

Just one hitch: Noto Mono (the monospace font) isn't the same width when boldfaced (in Notepad++ under Windows). That means you can't boldface part of what you're editing and have it stay lined up. For that, you still need Consolas (in Windows). However, that isn't Noto's fault. Noto does not supply a boldfaced monospace font (yet), and Windows has to fatten it up by itself.


50 years

It has been half a century. We still miss our Dad.

Further investigation of my father's death, some of it quite recent, confirms that he was murdered while on duty and disproves a lot of speculations and alternative theories that once circulated. In particular, I want to steer people away from a novel that someone self-published on Amazon a few years ago, giving a highly fictional account of the event but accusing real people of misdeeds without evidence. The sooner that novel vanishes into obscurity, the better.


M52 and the Bubble Nebula (NGC 7635)

My final picture from the Peach State Star Gaze, taken on October 1, is this one, showing the star cluster M52, the Bubble Nebula, and the surrounding rich field in the northern constellation Cassiopeia. This is in the plane of our galaxy but away from the galactic center, so there aren't thick star clouds in the background.

This is a stack of 25 1-minute exposures with a Canon 60Da and a 105-mm f/2.8 lens (for a total aperture of about an inch and a half). Here's a labeled image (courtesy of Astrometry.net) to show what you're looking at:

And here's the central part of the original picture, enlarged, with red boosted to help bring out the nebula. Look at the 11th- and 12th-magnitude stars in the cluster — fully resolved with this tiny aperture.


Spout of the teapot

The constellation Sagittarius looks like a teapot, and right at the spout of the teapot is a bright cloud of stars. Here's a picture of it, taken at Deerlick on October 1. Stack of 25 1-minute exposures, Canon 60Da, ISO 1600, Sigma 105-mm f/2.8 lens, iOptron SkyTracker.

Purists will call this the Gamma Sagittarii Star Cloud rather than the spout of the teapot. Suit yourself...


Pipe Nebula

Continuing yesterday's series, here are the Pipe Nebula and Snake Nebula (two dark dust clouds; the snake is at upper right; the bowl of the pipe is at the bottom, and the stem is outside the picture). These are in Ophiuchus, near the galactic center. You can see many more streaks of dark nebulosity in front of the thick clouds of stars.

Stack of 25 1-minute exposures with a Canon 60Da and Sigma 105-mm f/2.8 lens on an iOptron SkyTracker, at Deerlick. Compare what I got 6 years ago.


Field of Zeta Aquilae

I went to the Deerlick Astronomy Village on September 30 and again on October 1 to attend the Peach State Star Gaze. Both times, I brought along only a tripod, iOptron SkyTracker, Canon 60Da camera, and 105-mm f/2.8 Sigma lens, like this. My goal was to photograph some scenery along the Milky Way.

I came back with lots of pictures, which I'll present roughly in reverse order. So here's the last one:

This is the field of Zeta Aquilae (lower right) and the tail of Sagitta (upper left), with Barnard's E, a dark cloud, at the lower left corner.

What you're looking at here is part of the Great Rift, a dust lane in our galaxy that runs vertically through the middle of the picture. That is, you're not looking at a thin area of the Milky Way — you're looking at a heavy streak of dust that hides the more distant stars. You can see some of the brownish coloration of the space dust.

Stack of eighteen 1-minute exposures, 105-mm f/2.8 lens, Canon 60Da at ISO 1600.

Happy birthday, Melody!


Microsoft fixes Windows 10 astronomy camera and webcam problem

As far as I can determine, the notorious problem that caused many webcams and astronomical video cameras to fail under Windows 10 has been fixed.

It was fixed by Update KB3194496, which was distributed automatically by Windows Update on September 29.

Microsoft did not mention webcam or video problems in its list of things fixed by this update. However, my ImagingSource DFK21AU04.AS now works correctly with both its own software and FireCapture, and I am hearing that many others are having the same experience, including owners of Logitech and Skyris cameras.

To see if your computer has that update installed, go to Settings (the gear at the lower left when you press the Start Menu), Updates & Security, Windows Update, Update History.

Recall that this problem affects Windows 10 Anniversary Update (1607), the big update that many of us received at the end of July.

The simplest way to see if you are running version 1607 is to press the Start button. At the lower left, if the gear icon, power icon, etc., have words like "Settings" and "Power" continuously visible next to them, you are not running version 1607. In version 1607, the word "Settings" is shown only when you mouse over the gear icon.

Another way to check is to go to Settings, System, About, and look at Version. For more about Anniversary Update, click here.

Windows 10 Anniversary Update adds a useful (but optional) command-line-only Linux subsystem and other new features.

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