Michael A. Covington    Michael A. Covington, Ph.D.
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Photography for art's sake
Do you always have a right to your own opinion?
Dew-heater controller
Making software look right on high-DPI displays
Getting files to another computer fast
The Lunar X
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Making software look right on a high-DPI display

Many newer computers, including my ThinkPad, have high-DPI displays. That means their screens have appreciably more than 100 pixels per inch and are very sharp and crisp, and most of the software looks great. If some of yours doesn't, read on.

Most computers until recently had about 100 pixels per inch, such as my previous laptop, with its 17-inch, 900×1600-pixel display. Software is designed for displays about this size.

The ThinkPad has a 17-inch, 3840×2160 display, giving about 260 pixels per inch. This is a high-DPI display.

Obviously, if software were to address the pixels of the ThinkPad as if they were the native pixels of an earlier computer, everything would come out tiny. Instead, Windows scales it up, and usually gets it right. In fact, newer software addresses the screen using vector graphics and comes out very, very sharp. Older software is usually just magnified, and looks less crisp, but completely normal. Some software is partly one way and partly the other.

Some software goes wrong; part or all of it comes out either very tiny or very blurry. You can generally fix this by telling Windows to do the scaling a different way. Here's how I fixed an older version of Photoshop:


You have to find the executable file, which is usually somewhere in C:\Program Files. Then, "System" is usually the right setting, but try all the alternatives.

I had to do this for several pieces of software. The only one that foiled me was Virtual Moon Atlas 7.0, which makes the labels too small no matter what I do. Fortunately, Virtual Moon Atlas 6.0 is still available and works correctly with the "System" setting.

Getting data to another computer fast

I record my lunar and planetary video images on an old Asus UX32A notebook computer, often generating 20 GB of data in a single session. I then need to transfer this to the computer on which I process the images, which are distilled down to high-resolution still pictures.

And there are several ways to do this. What I've just learned is that some USB flash drives are a lot faster than others — and that the USB 3 ports on one side of the computer are appreciably faster than the one on the other side!

Here are speeds I measured:

Copying from the internal SSD drive to itself 175 MB/s
Speed at which the software records video files 64 MB/s
Fast USB flash drive on right-side USB port 53 MB/s
Fast USB flash drive on left-side USB port 29 MB/s
Fast (class 3) SSD card in SSD card reader 16 MB/s
Older, low-cost USB flash drives < 5 MB/s
Wi-Fi transfer to another computer on the network    8 MB/s

Bear in mind that these speeds are from a vintage-2013 computer; back then, I was delighted to get USB 3 at all. My new ThinkPad can write on the SSD card at 70 MB/s, but its speed writing to the new USB flash drive is the same as that of the old Asus.

Lessons learned:

  • A fast USB flash drive is a good investment. The one that is serving me so well is linked below.
  • Some USB 3 ports can be faster than others on the same computer — try them all!
  • With newer computers, SSD can be faster than USB flash. Try it.
  • Wi-Fi is very slow compared to any kind of removable flash media.
  • The best USB flash drive is probably not quite fast enough to record the video directly. But I'm going to try it. If it works, it will save me a step.

Here's the one that is working so well for me. Click on it for the Amazon link.


Short note

This ThinkPad has a color-calibrated screen, and with that in mind, I've adjusted the Daily Notebook's background color to be a bit bluer. This is retroactive to other recent months that use the same style sheet.


Dew-heater controller

Yesterday I finished an electronic project that had been sitting on my workbench since mid-2006. Back then, I went to the late lamented Ack Radio, Inc., in Atlanta, and bought, among other things, an enclosure and a small potentiometer and knob. The purpose was to build a new dew-heater controller for my telescope, to replace a temporary one built in 2001 (which I ended up using for 20 years).


What are dew heaters? Weak heating elements wrapped around the front lenses of telescopes to keep dew from forming. Left to itself, the lens radiates heat and actually gets colder than the surrounding air, thus attracting dew. With a couple of watts of heat, the lens can be kept at the same temperature as the air, eliminating the dew problem and actually making the view steadier by reducing air turbulence.

The amount of heat needs to be variable, hence the need for a controller. This one uses pulse-width modulation at about 450 Hz.


Changes made later: R4 is 22k, not 2.2k (to keep the LED from being too bright during observing sessions); a 7.5-amp fuse was added to the circuit in the 12-volt input, before any outputs.

This is the same circuit as I used in 2001 except for a better MOSFET; the one I used is on a heat sink but apparently doesn't need it, because with an "on" resistance of 0.16 ohm, it dissipates only 2/3 of a watt when carrying 2 amps continuously.


It's in a clamshell-type enclosure made of extruded aluminum; the circuit board fits into a slot and is held in place with dabs of contact cement (which is rubbery and can be peeled off if I ever need to repair the board). The big hook, for hanging the unit on an eyepiece rack, is a U-bolt with heat-shrink tubing over the threads on one side.

Building with stripboard

This construction project in fact used up part of the last sheet of stripboard remaining from about a dozen that I bought from a bargain counter in Germany in 1987. The exact same sheet is still made — it is or was a European standard — and one example is the BusBoard ST3U available from Amazon and other suppliers.

Stripboard has holes 0.1 inch apart (to match IC pins), connected by copper strips, which can be cut by twirling a 3/16-inch drill bit in one of the holes. Here are top and bottom views of my circuit board. You can see one place where I cut one of the copper strips in the wrong place and had to bridge it with wire.



Incidentally, this was done entirely with lead-free solder (Kester K100LD) and came out beautifully. Two hints: In modern times we put a little flux on almost everything before soldering it (I used a Kester flux pen), and lead-free solder only comes out shiny if there is absolutely no lead-based solder mixed with it.

On the top, you can see something unusual — row headers with pins missing (to make it easier to attach larger wires). Where do I get these? Simple. I attach the row header to the board, soldering only the pins that are going to stay, and then remove the other pins by heating them with a soldering iron to loosen the plastic so they can be pulled out.

Getting back to stripboard: It remains my preferred type of prototype board even though pad-per-hole board is nowadays much more common. As the name implies, pad-per-hole board has a small copper pad around each hole, not connecting to any other hole. You have to lay down wires to make connections. This can come out more compact, but it makes it harder to replace components — you can't just pull them out of their holes, you also have to deal with whatever is attached below deck. You can make components replaceable by looping wires around the holes they will occupy, as demonstrated here.

Prototyping with pad-per-hole board is described and illustrated here. I've accumulated so much pad-per-hole material over the years that I should try to get used to it. I think it works best with digital ICs that have a lot of pins but leave many of the pins unconnected.


The X on the moon

Picture Picture

For a couple of hours around the time of first quarter moon every month, there is a striking letter X formed by the light striking the walls of two craters. In the pictures, it's below center, on the left. I saw it around 8 p.m. EDT on March 20.

For the first picture, I just held my iPhone up to the eyepiece (14-mm Radian, on my 1980-vintage Celestron 5). For the second one, I used an ASI120MC camera to record about 4800 video frames, then stacked the best 50% and sharpened the result — the classic way to do high-resolution lunar and planetary work. There is less difference in the results than you might have expected.


Short notes

I haven't actually stopped writing in the Daily Notebook, but we've all been busy. Here are some short notes.

Fourth wave coming? Both in Georgia and nationally, the rapid decline of COVID infections has stopped or even reversed. This may just be an irregularity in reporting, but on the other hand it may be the start of a fourth wave. Friends, now is not the time to party like it's 2019.

(Official Georgia data below. Note the recent upturn, a false upturn in February, and a real upturn in October.)

[Update: One theory is that the virus has mutated and is more contagious.]

There are still some grounds for cautious optimism. The United States is finally vaccinating a substantial number of people. And if you look at the date of disease onset rather than of reporting, it's not so evident that we're having an upturn; maybe we're not. We'll see.

Vaccinated: Melody, Sharon, and I finally got the first dose of the Pfizer vaccine two days ago. For me, it produced mild cold-like symptoms and some soreness in my arm. Death to the viruses! Second dose is April 8.

New laptop: One of the many things going on is that I'm moving into a new Lenovo Thinkpad P17. This is a very generously configured machine with an 8-core, dual-threaded CPU. The idea is for it to be my main computing engine, even to the point that I may remote into it from my desktop when I want the comfort of sitting at a big screen. Its keyboard and screen are much more comfortable to use than on cheaper laptops, even Lenovo.


One year in

March 11, 2010, was the "last normal day" for FormFree, and the last time I worked in their Milledge Avenue office. A co-worker suggested that some of us who normally worked at home should come in, and I joined them.

That was the day the WHO declared the pandemic, and that evening, a pro basketball game was suddenly cancelled, followed by cancellations of almost all public events in the next few days.

Today, there are signs of hope. I'm cautious. Already I've prematurely expressed hope upon seeing the downturns after two waves, but they were followed by a much more deadly third wave.

The good news is that Georgia's spread rate (Rt) is estimated at 0.75, the lowest it has ever been, and if we can keep it that low, in a few weeks COVID-19 will be scarce.

But will we? Do you stop fighting a fire when it's 90% out? No, of course — you press on and kill it dead.

If my fellow Americans will do that, we can get rid of COVID. Or we can make it flare back up. Your choice.

Georgia data from https://dph.georgia.gov/covid-19-daily-status-report:

Analysis and forecast from https://epiforecasts.io/covid/posts/subnational/united-states/georgia/:

National data are similar to Georgia's.

Why did it drop? Several possibilities:

  • Vaccines seem to be doing more good than anyone expected. They are targeted to the most vulnerable people.
  • The epidemic may be "burning itself out" like a fire running out of fuel. Sadly, a lot of the people who were going to die of COVID have probably already done so. And a lot of other people have had COVID (possibly without even knowing it) and come out partly immune.
  • There may also be some pre-existing immunity due to other viruses and vaccines that people have had. This may also be why COVID hasn't devastated Africa.

Meanwhile we are all eagerly awaiting vaccination. My age group becomes eligible on Monday. If I were two years older, I could have already gotten it. This is perhaps the last time in my life that I will have been too young for something that I want to do.


Do you always have a right to your own opinion?

Adapted from a well-received Facebook posting.

Do you always have a right to your own opinion?

Actually, no.

If you're standing in the middle of the road and cars are coming, you don't have the "right" to the "opinion" that they're not. They'll hit you even if you choose not to believe in them.

That's because the oncoming cars are a matter of fact, not opinion. There is no real uncertainty about them. Those cars are there.

If someone believes they're not, that is not an opinion; it is an error.

An opinion is an estimate of the facts, which we use when the facts are not completely known. Just like estimates of my height or the value of my house, opinions aren't worth much unless they are based on the best information and reasoning that you can get.

I have gotten tired of people "having a right to an opinion" that COVID isn't real, or the media are all lies, or the medical journals are all fake, or the earth is flat, or the sky is full of pink elephants.

Some things are genuinely uncertain, and that is where opinions rightfully come in. The opinions of knowledgeable people are valuable, even if they don't all agree. Even if we can't get a final answer, we can at least rule out some possibilities, and say that some things are more likely to be true than others, and figure out what to investigate further.

But when people choose to believe and say something that they know (or ought to know) is false, that is not an opinion. It is not even a mistake. It is worse — a lie told to oneself.

Also — and this is a hard thing to say — I am sad, but have to put my foot down about something: There is a level of foolishness I don't tolerate in my circle of friends or Facebook friends list. If you give people false information that puts them in harm's way, you are not welcome.

I am very sad to have lost two friends whom I had known for decades. They went off the deep end into conspiracy theories, and while I hope and pray they will come to their senses, in the meantime I can't let them annoy or mislead my other friends.

There are many things about which well-informed experts disagree. For example, it's genuinely uncertain whether lockdowns were the best way to stop the early expansion of COVID. There's genuine controversy about what the minimum wage should be. And so on. On issues like these, I gladly hear all sides.

But everybody who knows anything about COVID knows that it is a deadly disease, and that it has killed a lot of people, and that the vaccine is safe and effective, and the reporting in medical journals is, by and large, honest. Like the cars in my first example, these are facts, not matters of opinion. Saying something else doesn't change them.

If you deliberately make yourself ignorant — by living in a fantasy world and listening only to extremists — and then tell people "not to live in fear" and not to wear masks or get vaccines, you are on the same level as if you were telling people to walk in front of oncoming cars. You are putting other people in danger, and I can't tolerate it.

Lesser forms of foolishness may not put people in danger, but they waste time and create confusion. I care about what's true in the real world, not what ignorant people make up in their own minds, or what gullible people swallow from propagandists and quacks.

Of course you have a right to form your own opinions.

That means nobody can compel you to hold a particular opinion. Even if they try, they can't, because forming an opinion is an act within your own mind.

It does not mean that you have no responsibilities when forming an opinion, or that any opinion you might choose is as good as any other. If you are not a fool, you will want your estimates of the truth to be as close to the real truth as you can get them. That's what estimates are for.

I want to thank several Facebook readers who brought up important points and suggested improvements to this explanation. It was well received. I may have put something into words that many people did not quite know how to express.


Astronomy 51 years ago and a historic Atlanta sign

Here's a page from my astronomy notebook, 1970. That was almost three months after my Criterion RV-6 arrived, and I was using it avidly to view Saturn. Standard practice was to make drawings, since no good way of photographing planets from earth had been invented (there was nothing like modern digital video imaging). So here's one observation:


On that day (Saturday, Nov. 28, 1970; Nov. 29 GMT) I had been in Atlanta visiting cousins and had made a very interesting visit to Star Photo, a major camera store at the intersection of Ponce De Leon and Argonne Avenue. Then we drove home to Valdosta and I viewed Saturn.

Star Photo was diagonally opposite the historic Krispy Kreme doughnut shop that just recently burned down and is being rebuilt. Interestingly, the giant Kodak sign from Star Photo is still there and there is a move to designate it a historic landmark (see AJC coverage). To see a picture of the building itself some years ago, click here.

Another photo for art's sake


This isn't the definitive treatment of this tree; I'm going to try again. It has been catching my eye because parts of it are lighter than the sky background, and parts are darker.


Photography for art's sake

I used to attempt art photography nearly every day. I've been away from it most of the time for several years but have decided to resume trying. So here's a picture I took in a downtown Athens alley the other day:

Copyright 2021 Michael A. Covington
This and all photographs in the Daily Notebook are covered by copyright.
Many contain hidden copyright information. Please ask permission before copying.

iPhone SE, postprocessed in Photoshop.

A one-hour vacation

As a post-Valentine's Day resolution, Melody and I have started taking short rambles together almost every day, exploring the area around Athens and occasionally finding something picturesque. The other day we went to the Elder Mill Covered Bridge in nearby Watkinsville, and both of us got some memorable pictures. Here's mine:

Copyright 2021 Michael A. Covington

Here's a more conventional view of the bridge and of the sign describing it.



University in time of pestilence

I can't totally do without the University of Georgia's libraries, and yesterday (Feb. 28) I made a short expedition to the Science Library to see if, in fact, I can comfortably read there while wearing a COVID mask. The answer: it can be done but isn't pleasant. To control fogging of my glasses, I need a mask with a long wire above the nose, carefully bent to the right shape.

The University is open but requires masks indoors. The biggest COVID precaution is one that may become a permanent part of our culture: avoid needlessly crowding close to strangers. So the students are much more spread out than usual. This is feasible because about two thirds of them aren't there.

As you can see, they've put a mask on Godwin (a notorious statue that represents God as seen from one side, Darwin from the other, and from the front, and old man with an eye problem). And there are stern warnings at entrances to buildings.



I spent some time looking at an interesting book, Efron and Hastie's Computer Age Statistical Inference, and checked it out.

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