Michael A. Covington    Michael A. Covington, Ph.D.
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Ichthys

Daily Notebook

Popular topics on this page:
The digital Dark Ages
HOW I AM GOING TO PHOTOGRAPH THE ECLIPSE

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2017
July
17

"You have such an expensive hobby..."

I never know how to respond when someone sees my astronomy equipment (like the setup shown below) and says, "You have such an expensive hobby!"

Are they admiring the advanced equipment, admiring my supposed wealth, or trying to say they could never afford to do astronomy?

The fact is, my eclipse equipment cost maybe 1/10 as much as the car I'll be transporting it in, which is a rather cheap car. My astronomy hobby is less expensive than any kind of boat or motorcycle, or going to Florida every year, or trading cars even slightly more often than I do.

It's true that a good telescope and mount cost a couple of thousand dollars. But that's a one-time expense. The telescope doesn't eat. It doesn't consume supplies and maintenance. One of my telescopes has been in regular use for 37 years. It cost $750 back then, so, adjusting for inflation, it has cost me about a dollar a week. That's less than I spend on vending-machine snacks.

2017
July
16

Latest granddaughter

With Melody's inability to travel, we actually had not yet met our newest granddaughter, Emily Elizabeth Barrett, who is a few days short of one year old. To remedy this, Cathy and Emily flew in on the 14th and are here for a long weekend. Together Cathy and Sharon cooked pasta bolognese, and we had dinner with guests at the dining table (nephew Aaron Paul and his wife Emily) for the first time in several years.

Paradoxically, even though she's facing surgery, Melody is in better physical condition than she has been in a long time. She goes to the hospital on Monday. We appreciate everyone's prayers and best wishes.

2017
July
14-15

How I am going to photograph the eclipse

Today (July 15) I did a "dry run" with my setup for photographing the eclipse. It is the right time of day, we have good weather, and there is a sunspot, enabling me to check the sharpness of the pictures. (A spotless round sun looks about the same whether it is critically sharp or not.)

First, note that I am more interested in seeing the eclipse than photographing it. I am only going to devote 1/4 of totality to photography. If I don't have good pictures by then, I'll stop trying. Most of the time I want to just look, to see the things pictures don't show very well.

Second, no telescope is involved. This is a camera with a telephoto lens. The telescope mount will make it easier for me to keep it aimed at the sun during the whole eclipse, but a plain camera tripod would work as well.

Here's the gear:

From top to bottom:

  • Canon 300-mm f/4 telephoto lens in tripod collar.
  • Short ADM dovetail to hold the tripod collar to the mount.
  • (Not visible:) Thousand Oaks Solarlite filter, for partial phases, to be removed for totality.
  • Canon 60Da camera body.
  • Cable release (including a timer).
  • Celestron AVX mount head.
  • Small iOptron counterweight (because Celestron's counterweight is too heavy to balance this camera and lens).
  • Tripod.
  • 12-volt battery pack.

One detail: Compared to what you see here, the camera and lens will be rotated 90 degrees counterclockwise in the tripod collar so that the pictures will extend east-west rather than north-south. The corona is likely to extend farther east-west, and tracking errors in that direction are more likely.

The exposures I'm going to use are:

PARTIAL, WITH FILTER:
ISO 200, f/10, 1/2000 second
TOTALITY:
ISO 800, f/10, 1/15 second ± 2 stops

The exposures in the test run were slightly different. The lens is being used at f/10 rather than wide open in order to make it more forgiving of focusing errors.

I will use Canon automatic bracketing (AEB) so that all I have to do is press the button 3 times and I get 3 exposures over a range of ± 2 stops. During totality, all I will have to do is press the button three times, then maybe do the same thing again once or twice.

Here is a picture from the practice run, first the whole field and then the center, showing that the sun image is reasonably sharp. If I were going for higher quality, I could stack several images, but this is good enough.

2017
July
13

Melody's update

As Melody continues to recover from revision (reworking) of an infected hip replacement, first let me give you the good news:

She can walk with a walking stick.

The other day, she cooked for the first time in more than a year. She made corn pie, which is cornbread with corn grains and other goodies in it.

And tonight (July 12) we went out to dinner for the first time in more than a year. We went to Fatz Café (Athens) and had grilled salmon.

But there's bad news. The infection doesn't seem to be gone, and on short notice she is going to have another operation to clean out the hip joint prosthesis and replace parts of it. That will be Monday. Your prayers are appreciated.



Jessica the box turtle returns for a visit

About 20 years ago, we kept box turtles as pets, not realizing that the laws of Georgia did not permit it. Over the years, a few of them escaped. One of the escapees was a young female box turtle with unusually dark coloration which we had named Jessica because she was given to us by a neighborhood boy named Jesse.

Yesterday (July 12), I saw a box turtle in the side yard and took a picture. When I came back in a few minutes, the turtle had vanished, but I saw several unfinished nests in the soil, along with a couple of spots that might be a finished nest. (Box turtle nests are holes in the ground, well disguised, and in the late autumn the baby turtles dig their way out.) Aha, I thought, we have a nesting female.

I sent Cathy the picture, and she confirmed that this is Jessica. (It's hard to see in the picture, but she has deep red eyes rather than the usual yellow.) She has probably been living in the wooded northwest corner of our yard the whole time. We'll keep our eyes open for her, and for her babies.

The lifespan of a box turtle is slightly longer than that of a human being, and this one looks the right age to have been adolescent 20 years ago.

Cathy points out the distinctive shell pattern, which looks almost like a set of asterisks. (I hadn't noticed it because box turtles in Valdosta, where I grew up, often looked like that, but it's not common here.) We think Jessica is a crossbreed of Terrapene carolina carolina with Terrapene carolina bauri; our recollection is that the boy who gave her to us had brought her up from farther south. Click here to see what box turtles in North Georgia more commonly look like — more like the shell of a true tortoise.

[Further update:] Later the same night, I stepped out to look briefly at the stars and heard something like a pig snorting. It turned out to be an armadillo, right where I had found Jessica. Fortunately it did not dig up the nests. As I shined a flashlight on it, it slowly ambled across the back yard, as if it weren't afraid of me at all. This is the first armadillo I've seen in our yard, though they have been common as nearby roadkill for several years.

2017
July
9-12

The digital Dark Ages

If you've studied history, you know that it is relatively hard to find out what was going on in Europe between about 500 and 1000 A.D. Compared to earlier and later periods, not a lot of records survive. Those are the Dark Ages, so called not because they were dark, but because we can't see into them.

In the same way, I'm afraid scholarly research published between 1980 and 2000 has become too hard to find. It's not old enough to be mentioned frequently in later publications, and not new enough to be available in digital form on line (most libraries' digital collections start around 1995 to 2000).

Since the digital Dark Ages span the first 20 years of my academic career, I'm concerned. Libraries need to digitize and index publications back to at least 1950 as the opportunity arises.

2017
July
5-8

How I fixed Chrome when it was slow

I use Google Chrome for web browsing and use my Google account to synchronize the bookmarks and settings between different computers, both Windows and Linux systems.

On one laptop, an Asus UX32A, Chrome had gotten slow, especially when browsing sites that load many ads or other components separately, such as www.cnn.com. It was taking 2 minutes to load CNN's main web page, as opposed to 15 seconds with Microsoft Edge.

Why was only one laptop slow? Its disk was over 75% full, which spurred Chrome to cut back the space it was using for the cache. I don't know if 75% is the threshold; what I know is that freeing up some disk space made a big difference. To learn more about Chrome's cache, see this link. In Chrome, type chrome://net-internals/#httpCache and look at "Max size," which should be about 300 million bytes.

To free up disk space on your Windows 10 system, in File Explorer choose This PC, right-click on drive C, Properties, Disk Cleanup, Clean Up System Files. I had about 40 GB of previous Windows versions, which I gladly tossed. (Windows 8.0 no more!)

I did some other things that also improved performance:

  • Got rid of the obsolete OneWindow extension in Chrome, which I used to need in order to view some badly designed web pages. (OneWindow turns pop-up windows into pop-up tabs. If you need it, keep it.) In Chrome, click More Tools, Extensions.
  • Forbade cnn.com and a few other sites from using cookies. (This is a good thing to do if you regularly visit a site that loads slowly because it's covered with ads.) In Chrome, click Settings, scroll all the way down, click Advanced, scroll up to Content Settings, Cookies, Block.
  • Blocked Adobe Flash (Macromedia Flash), which is obsolete and was crash-prone on some sites. That's also in Content Settings, Flash.
2017
July
3-4

Slightly more retired

Very alert readers will note that the title "Adjunct Professor of Computer Science" has disappeared from the masthead of the Daily Notebook.

I've decided to give up that title (probably retroactive to July 1, if you look at the personnel records), since I don't really need it for any privileges, and it does not accurately describe any work I'm currently doing.

It doesn't make a lot of sense to have a faculty title and an adjunct title at the same university, anyhow. It is a historical artifact, dating from when the Institute for Artificial Intelligence was not part of the Franklin College of Arts and Sciences and its one and only faculty member (me) was therefore not part of the College faculty.

2017
July
1-2

Short notes

 Happy 150th, neighbours to the north!

Other writing projects are taking the bulk of my time, and the Daily Notebook may languish this month while I get other things done. But it won't stop completely.


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