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

Daily Notebook

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Last-minute eclipse FAQ
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2017
August
25-31

Still more about eclipses and eyes

Further to my entry the other day, I've been reviewing the medical literature on eclipse eye injuries, both old and new, and here are a few tidbits.

  • Early reports are that the number of serious eye injuries this year is small.
  • This year's characteristic misconceptions are two:

    • People think eclipse goggles are similar enough to sunglasses that sunglasses can substitute for them.
    • The term "pinhole viewer" is still leading people to imagine they are supposed to look through the pinhole.
  • Full recovery after a few months is usual, but when someone recovers to 20/20 vision, that doesn't necessarily mean there are no small blind spots, or that their night vision and color vision are fully normal. The latter two things are not usually tested. Nor do we know how well the injured eye will hold up in old age.
  • Some people don't notice their injuries until weeks or months later. If the damage is only to one eye, it may not be discovered until the victim attempts a one-eyed task such as aiming a rifle.

Most injuries happen to people using no eye protection, or doing something obviously unsafe, but there is a steady, though small, supply of "impossible" injuries where the patient attributes the injury to something that could not actually have produced it, such as staring at the sun once for 2 seconds, or using an undeniably safe viewer.

Some conclude from this that there is, after all, no safe way to view an eclipse. But two alternative explanations are likely.

One is that the patient is not telling the whole story. One researcher pointed out back in the 1940s that soldiers and children might be punished for disobeying safety instructions, so of course they won't admit to doing so. Others might fear their health insurance wouldn't cover a self-inflicted injury, or just be embarrassed.

The other is that eclipse warnings led the patient to notice an eye problem that had some other cause. After all, other eye disorders do not vanish on the day of an eclipse; they can continue to crop up at the same rate as any other day, and some will be misattributed to the eclipse if there is one at the time.

I would rather believe either of these than believe that eclipse injuries defy the laws of physics.

2017
August
24

Your eclipse glasses won't go bad

A couple more pieces of eclipse flotsam and jetsam before we move on to other things.

Your eclipse glasses will not go bad when they're a few years old. I suggest keeping them to look for sunspots (which are going to be more numerous in a couple of years) or donating them for educational use.

NASA says: If your eclipse glasses or viewers are compliant with the ISO 12312-2 safety standard, you may look at the uneclipsed or partially eclipsed Sun through them for as long as you wish. Furthermore, if the filters aren't scratched, punctured, or torn, you may reuse them indefinitely. Some glasses/viewers are printed with warnings stating that you shouldn't look through them for more than 3 minutes at a time and that you should discard them if they are more than 3 years old. Such warnings are outdated and do not apply to eclipse viewers compliant with the ISO 12312-2 standard adopted in 2015.

Those warnings — don't look for more than 3 minutes and don't trust them if they're a few years old — are apparently boilerplate language accidentally copied from the instructions for some older kind of filter that is not strictly safe by today's standards.

And from Thousand Oaks Optical, America's premier maker of sun filters, I have this:

We recommend discarding after 10 years due to the paper frame. The lens material will last 30+ years.

There. That settles it. I didn't understand those warnings, and it turns out the reason I didn't understand them is that they were wrong.



Short notes

Here come the fake eclipse pictures. People are starting to circulate stolen copies of science-fiction space art — anything that looks a bit like a solar eclipse — as if it were pictures of this week's eclipse. I say "stolen copies" because the original artists usually aren't credited. Often people say the picture came from NASA.

Think about it: we all saw the same eclipse; anything wildly different is not it. And don't circulate art if the artist isn't identified or doesn't consent.

Eclipse fatality: A car plowed into a crowd of eclipse watchers in Kentucky, killing one of them. Not terrorism, but a tragic accident. I am wanting to know more about what caused it, and in particular, whether eye injury or misuse of eclipse glasses was involved. The victims were safely standing on a sidewalk; the car ran off the road.

[Update:] A source connected with the investigation tells me there is presently no evidence that either the eclipse or eclipse glasses were involved, but they are keeping this in mind. Looking at a map and the published description, I see that what happened is that the car failed to follow a curve in the street; going approximately straight where the street curved, it crossed a sidewalk and ended up on a side street. A tragedy whether or not it was eclipse-related.

2017
August
23

Eclipse observing log

The following are my notes, essentially from my astronomy notebook, although nowadays they are kept in digital form. I've added a few pictures.

These are my detailed observational notes, written 2 days after the eclipse, based partly on audio recordings made immediately after the eclipse. These notes are written in HTML so they can also be published as an entry in the Daily Notebook.

My goal was to take competent (not exceptional) photographs and see the eclipse visually.

Other logs: Besides these brief, structured notes, I have a file-by-file log of all the digital images, generated with EXIFLOG, and a set of audio recordings. The most important audio recording goes for 27 minutes starting about 20 minutes before totality and contains an accurate time signal near the beginning. At that time I was speaking on the PA system to point out important events as they occurred. I have been told that some of my words were broadcast by WSB Radio.

Click here to hear my narration of the beginning of totality.


NASA map with Hiawassee indicated.

Eclipse data: At Hiawassee, totality was predicted to start at 2:35:01 p.m. and last 2 minutes and 27 seconds, according to eclipse2017.org. I had with me a watch set accurate to the second.

Site: I was in the upper parking area of the Georgia Mountain Fairgrounds, just south of the pavilion and just west of the rhododendron garden (Hamilton Gardens), with my equipment set up on the grass. Google Maps gives the latitude and longitude as 34°58'02.5"N 83°46'16.2"W (34.967354, -83.771172).

Google Maps does not give altitude. Elevationmap.net gives the altitude as 1970 ft = 600 m.

The site has street lights which did not come on, thank goodness. My understanding is that they are on a switch because they are not used when the fairgrounds are not in use.


Setting up (11 a.m.). My telescope is protected by a "space blanket" of aluminized plastic.


Looking west (downhill) from my setup. Note clouds starting to form.

Travel and local arrangements: I was there as the "eclipse scientist" for the organized public viewing event; I thank the Chamber of Commerce for their hospitality and Candace Lee in particular for her hard work. I stayed in the Lake Chatuge Lodge, a good hotel next door to the fairgrounds.


Back porch of the Lake Chatuge Lodge.

Weather: Clear with slight high haze; during the partial phases, cumulus clouds began to approach from the south, and at totality, there was a large cumulus cloud bank to the south, up to more than 45 degrees above the horizon, but not blocking the sun. After totality, the clouds moved north, and we missed most of the partial phases after totality. The National Weather Service recorded a clear sky until 6 p.m. at Andrews-Murphy Airport, about 30 miles north of us, in somewhat different terrain.

Temperature at Andrews-Murphy Airport, according to the National Weather Service, peaked at 87 F around noon and dropped to 77 F right after totality, then came back up.

Equipment: Celestron AVX mount with one small iOptron counterweight, AVX tripod, Canon 60Da, Canon 300/4 telephoto lens (used at f/10), Thousand Oaks Solarlite filter (for partial phases), Canon cable release.

The mount was powered by a 17-AH battery pack, which barely showed any depletion after four hours of use.

Daytime polar alignment: Altitude by using the iPhone as an inclinometer, and azimuth by drift method on the sun. Finding true north with the iPhone compass and with a separate conventional one was difficult because of something magnetic in the area, possibly on my person.

Partial phases: Thousand Oaks eclipse glasses gave a very sharp view, and I was able to see the sunspot group with no further optical aid. I also got hold of one pair of glasses, called "Eclipser," possibly counterfeit, that were too dark (density 6.5 to 7.0, I estimate). Counterfeit ISO certifications and uncertainty about eclipse glasses were major problems at this year's eclipse.

Shadow bands: Seen briefly (for 15 seconds) starting about 35 seconds before totality. Much less of a show than at the 1984 annular eclipse. That may be partly due to the slightly hazy sky. Also, at a deep annular eclipse, the sun remains a narrow sliver for a longer time.

Baily's beads: Not observed, or not distinguished from diamond ring effect. Others' photographs show Baily's beads as a small cluster of beads close together.

Diamond ring effect: Dramatic at both the beginning and the end of totality.


Success!

Sun during totality: The corona was very bright close to the sun (out to maybe 1/4 solar radius) and then trailed off more sharply than photographs lead one to expect. Although I mentioned coronal streamers in my audio narrative, I have no distinct memory of seeing the corona extending more than maybe one solar radius from the sun. The corona was more active than it could have been at this point in the sunspot cycle, but still rather compact compared to other eclipses.

A prominence was clearly visible to the naked eye at the 5 o'clock position (to the right of the southernmost point on the limb). I saw some indication of other prominences also.

I wish I had taken pictures with shorter exposures. My shortest exposure (1/80, f/10, ISO 800) shows the inner corona well; longer exposures added lens flare without picking up much more corona, and no exposure was short enough to catch the prominences properly.

Memorandum: There are two astronomical subjects that bring out lens flare: the Pleiades and a total solar eclipse. (The Pleiades are a star cluster that includes some rather bright stars.) I was not sufficiently forewarned about solar eclipses. Next time I'll probably use my apo refractor and test it taking overexposed pictures of the moon.

Allocation of time: Once I saw I had a successful digital image, I refined the focus and spent too much time photographing, not turning fully to visual observation until about 45 seconds before the end. In the future, I will use computer control to automate the camera.

Another blunder was leaving my binoculars too far away from where I was standing, so I could not grab them during totality.

Sky during totality: I was surprised by the high light level, both from the bright inner corona and from sunlight around the horizon and dim light on the cloud bank (which looked more than moonlit, less than sunlit).

Venus was very conspicuous in the west. Jupiter, low in the east, was clearly visible. I did not try to identify other planets or stars.

Some kind of aircraft with red and green lights was hovering very quietly in the southwest, apparently below the cloud bank. It has been suggested that it was a drone (a quadcopter) and was only a few hundred feet above the fairgrounds. That is quite possible.

After totality: The clouds moved north and obscured the sun.

Traffic and infrastructure: The drive up from Athens, via Highways 441 and 76, the day before the eclipse, was uneventful and there was no traffic congestion. The trip back home, however, was difficult. Hiawassee to Clayton was all right, but from Clayton to Tallulah Gorge we crawled at an average speed of 6 mph. (I assume people from other sites were coming down on 441.) North of Tallulah Gorge I took a "long shortcut" on the old Highway 441, passing by a hydroelectric plant and a recreation area; when I rejoined new 441, traffic was moving much better, though still occasionally congested, and I completed the drive in less than 6 hours. However, when I crossed I-85 at 9:15 p.m., the inbound lanes (toward Atlanta) were still bumper-to-bumper.

Internet and cell phone infrastructure were predicted to be congested, but in fact I had no trouble with cellular telephony at the fairgrounds and was able to connect to the Internet through the iPhone and e-mail pictures to the Athens newspaper.

Next: Texas in 2024? Chile in 2019?

2017
August
22

Eclipse picture gallery

All pictures Copyright 2017 Michael A. Covington.
If you wish to reproduce them for any purpose, please ask permission.
Prints will be available for purchase — watch this space for information.

The first five pictures are exposures of 1/2000 second, f/10, ISO 200, with a Canon 60Da and Canon 300/4 telephoto lens and Thousand Oaks solar filter, tracking the sun on a Celestron AVX mount. The last picture is a stack of three exposures of 1/80 second, ISO 800, with no filter, processed to bring out low-contrast detail.

No pictures were taken of partial phases after totality because clouds interfered.

2017
August
21

Success!

It was a long day; much was accomplished; and I'll tell the rest of the story later. This is a very preliminary rendition of a single exposure; an HDR stack is coming later. Canon 300-mm f/4 lens at f/10, Canon 60Da body, ISO 800, 1/80 second.

2017
August
18-20

The eclipse and your eyes: Some facts

If you're looking for authoritative information about eclipse eye safety, click here (or here). And read on...

Yes, you need eye protection, but no, eclipses do not blind people by the thousands.

In fact, eclipse eye injuries are now rare, probably because people know they need to take precautions, and good filters and other viewing aids are available. Be safe, but don't be unduly scared.

This paper by eminent optometrist Ralph Chou summarizes (on pp. 3-4) the experience of the past 50 years. There was a bad episode in 1962 in Hawaii when several people apparently got permanent eye damage. That led to panic at the 1963, 1970, and 1976 (Australia) eclipses ("the only safe way to watch the eclipse is on television," they said, which was not true then and is not true now).

Then, somehow, permanent eye injuries almost stopped, probably due to better public education. At the 1979 eclipse in Canada, the only people injured were deliberately disobeying instructions. (No data on the U.S., where the eclipse was also visible.) After the 1999 eclipse in England (which reached a huge population), 70 injured people were identified, but all of them recovered completely after months.

I want to underscore Dr. Chou's concern that warnings must be accurate, not exaggerated. If safety warnings are exaggerated, people learn to disregard them. He points out that a student who is told there is no safe way to view the eclipse, and then learns that others saw it without harm, will feel cheated out of the experience. You will have taught him to distrust safety warnings, whether they are about eclipse viewing, drugs, AIDS, or anything else.

I am flattered to find myself in the bibliography of Dr. Chou's paper. In fact, his warning about safety warnings is an echo of something I wrote in the 1980s, which Jay Pasachoff picked up. I think it is an important point of ethics. Spread the word!

Barring unforeseen developments, this is the last Notebook entry until the day after the eclipse. I have plenty of other things to do. See you on August 22!

2017
August
16-17

Fame thrust upon me

UPDATE: Click here to see a re-edited video that includes parts of my interviews. I don't know how long it will be up.

You probably never thought of me as a Spanish-speaking TV personality, and neither did I. But today (Aug. 17), despite a sore throat and my somewhat inadequate Spanish, I was interviewed at length by Telemundo Atlanta. Nobody else could talk about the eclipse in Spanish!

They gave me an enormous amount of time, about 6 minutes in one 30-minute newscast, nearly 7 minutes in the second one, and a reprise of about 5 minutes in the 11 p.m. newscast. That is more than high-ranking politicians usually get. I think it reflects the fact that there has been almost no eclipse information given out in Spanish. But if you want some, click here.

Here you see Annie Tejada asking me about the eclipse. There will be links to view the video, at least briefly. I have a recording but am not at liberty to put it on the Web.

Need eclipse information? Click here.

2017
August
14-15

Carport? What's a carport?

My big vocabulary got the better of me. I know what a carport is, and other people don't.

It didn't occur to me that this is arcane knowledge. I've known what a carport is since I was four years old, at least.

But other people simply don't understand when I say "go to the carport door" (the preferred entrance to our house at present).

It turns out that unknown to me, carports are a southern, 1960s-1970s thing. Newer houses here have enclosed garages, and so do houses of all eras in colder climates.

So what should I say? "Go to the side door?" It's not on the side. "Go to the back door?" It's one of two doors in the back, but "back door" might work because the other one isn't visible.



Charlottesville — 2 more points

I have a theory about the people who march with torches and Confederate and Nazi flags.

I think they don't distinguish reality from fantasy the way the rest of us do.

I think many of them have not really made up their mind whether they're playing a fantasy game or actually trying to be part of American politics. Look how surprised some of them are to find out this morning that their employers and neighbors want to ostracize them.

I've seen some of them heckle web sites and Facebook members who criticize them (which is why most of my Facebook postings on this subject are not public, and this blog does not have a comment section). They seem to be complete dupes of propaganda/fantasy web sites. They would believe pigs fly if a certain site said it. They will not believe the sky is blue if CNN says it. They say, and claim to believe, whatever feeds their anger and their game.

In short, the idea of testing one's beliefs against objective reality does not seem to be part of their mindset. For them, it's what you can say and feel, not what is real.


It is gratifying that all of a sudden, everybody believes in objective ethics. Racism is not just another opinion, it is objectively wrong.

The trouble with Trump's "all sides" speech is that it echoed the ethical relativism that was, until just now, so popular: "You have no right to impose your values on me." "Don't be intolerant."

Until just now, ethical relativism has been more popular with the left than the right. It has been especially fashionable among academics.

But a lot of us have joked all along that anyone will abandon ethical relativism if you steal his wallet. All of a sudden, the theft will be objectively wrong, not just a difference of opinion.

Perhaps also if people threaten him with torches.

A point about tolerance: I am in favor of free expression of ideas. I want the alt-right to be refuted, not silenced by force. But people need to take responsibility for what they say. You can't wave a Nazi flag one evening and expect your neighbors the next morning to welcome you into their community.

2017
August
13

Charlottesville

I call on all my fellow Christians to condemn all manifestations of "white nationalism" and racism in the strongest possible terms.

Traditionally, these people call themselves Christians and try to insinuate themselves among us. It is critical for us to tell the world that we are against what they stand for.

Matthew 7:22-23 applies.

Extremely important point: This is not about heaping contempt on people. I hate Nazism, not Nazis. Our Christian marching orders do not allow us to hate people. We must not get caught up in shallow expressions of contempt directed at individuals or groups of people. If you use my graphic below, please note that it is about rejecting beliefs and behaviors, not despising fellow humans.

Reuse of this graphic is encouraged.

2017
August
12

Eclipse glasses — fear, panic, and deception?
How to check yours, and how to do without them


SAFE eclipse viewers from Thousand Oaks, a reputable manufacturer

By now you've probably seen headlines that "counterfeit eclipse glasses are flooding the market."

Not exactly flooding. The only confirmed cases I've encountered came from third parties selling through Amazon. (Amazon was vulnerable because it allows individuals and small businesses to sell through the Amazon web site.) There may be others, of course, especially in the last few days before the eclipse.

Now I'm afraid people are going to miss seeing the eclipse through perfectly good glasses because of undue panic.

And as of today (Aug. 12), Amazon is giving refunds on a lot of solar filters, including some expensive astronomical gear that is above all suspicion, simply because they haven't received proof that it has the proper certifications. Amazon is erring on the side of excessive caution. Not everything that gets an Amazon warning and refund is actually unsafe.

Bear in mind that although it's a good idea, the ISO certification for solar filters is new, and many perfectly good filters didn't receive it because they were made earlier, or may never receive it because, designed for use with telescopes, they have a slightly lower density.

Note that ISO and NASA don't test glasses or filters. ISO publishes a specification, and manufacturers tell you whether their product meets it. That means you have to be able to trust the manufacturer.

Also, the AAS list of reliable manufacturers and vendors is not the last word. There was no advance plan for an approved list, so no opportunity for smaller vendors to get on it. Everything on their list is reliable, but don't assume that anything not on their list is not reliable.

I saw this coming. Besides Amazon's misguided entanglement with no-name third-party vendors, there were two other bad decisions:

  • By relying on information printed on the eclipse glasses, the whole community has made it easy for counterfeiters to print the same thing on glasses that aren't right. Anybody can print anything. We should have been emphasizing the supply chain instead.
  • By making a huge number of different styles, the manufacturers made themselves unrecognizable. The paper frames of eclipse glasses can be any color, with almost anything printed on them. You can't recognize manufacturers by their look.

How to check your own eclipse glasses:

You cannot test the UV or IR absorption of eclipse glasses by yourself, and hence you can't prove that a pair is safe. However, you can quickly check for signs of trouble.

First, are the filters shiny, either aluminized or black? Normally, eclipse glasses are made of thin flexible plastic and are shiny (silver or gold) on at least one side, maybe both. Some are shiny black on both sides. Safe filters made of other materials do exist, but in that case, you should make sure of where they came from. Anything that is vivid red, green, or blue is not eclipse glasses.

Second, are they dark enough? You should not be able to see anything through the filter except the sun, reflections of the sun on shiny metal and the like, and very bright electric lights (filaments and LED elements only; not fluorescent lights). If you can see people, scenery, etc., outdoors on a sunny day, the glasses are not safe. (That was the case with the counterfeit glasses that turned up on Amazon.)

While you're at it, make sure the filters don't have holes or scratches that let extra light through, not even tiny pinholes.

Third, if they pass the first two tests, are they from a reputable manufacturer? Three of the best are Thousand Oaks, American Paper Optics, and Rainbow Symphony. A fuller list is here.

And do you know how they got to you? Anybody can print anything, so watch out for unknown supply chains. All the major stores (Walmart, Lowe's, 7-Eleven, etc.) and all the major astronomical and educational organizations are OK. As I said, the only known problems arose because third parties are allowed to sell through Amazon.

Finally, keep things in perspective. Even the fake eclipse glasses that showed up on Amazon were not actually proven to be dangerous. I don't recommend using them without further checking, of course, because the false certification printed on them shows that the maker was up to no good. We don't know where they came from or how far out of spec they were.

But bear in mind that the ISO standard is very strict, and some perfectly safe filters don't meet it. Filters may lack ISO certification simply because they're older, or because they are designed for telescopes and deliberately have a slightly lower density to allow shorter photographic exposures. The ISO standard requires a logarithmic density of 6.0, but optometry researcher B. Ralph Chou has found that densities as low as 5.0 are sufficient to prevent eye damage. It's not a matter of a sharp threshold.

And if you don't have eclipse glasses or don't trust yours, you can still see the eclipse safely with no equipment at all, by looking at the shadow of a piece of paper with a small hole in it, like this:


Photo by Richard Dasher, used by permission

Enjoy the eclipse, don't panic, but be safe.

2017
August
10

Something Zeiss to look through

Melody gave me a premature birthday present (more than a month premature) that will help me see the eclipse and many other things: a pair of Zeiss Terra ED 10x42 binoculars. As often happens, I found them myself, at a closeout price because Zeiss has just upgraded them slightly and this is the old model, and then we designated them a birthday present.

Zeiss binoculars for just over $300? It can happen. "Terra" is Zeiss' economy line, designed in Germany but made in China. They're not as rugged as the higher-priced models, but for astronomy, one doesn't need great ruggedness.

They are the best binoculars I've ever had. They're not perfect; no binoculars are.

I should explain how to evaluate binoculars for optical quality. First look for misalignment (the two sides not aimed in quite the same direction); if the error is small, you won't see double images but your eyes will get tired. These binoculars are in excellent alignment.

Next, judge sharpness and contrast. The trick is, all binoculars are much sharper in the daytime (when the pupils of your eyes are smaller) than at night; it's like stopping down a camera lens. So the only sure test is to look at the starry night sky.

Cheap binoculars are sharp only in the very center of the field. No binoculars are perfectly sharp all the way to the edges unless they've chosen to give you an unusually small field. The reason is that most people would rather have a wider field than have perfect sharpness all the way to the edge.

These Zeiss binoculars have an unusually wide field, 60° apparent, about 6° true field, and the middle 75% of it is quite sharp. That is impressive. By masking off the lenses, Zeiss could have given us perfect sharpness with a 45° field, but I'm glad they gave us the extra area even though it's not perfect.

They are also surprisingly light and compact, lighter than the Pentax 8x40 binoculars that were, until now, my best. Thank you, Melody.

During the eclipse, I will use these only during totality. At any other time they would require sun filters in front of the lenses.

2017
August
6-9

Is this eclipse a warning from God?

This is mainly for my fellow Christians, but others may be asked scientific questions related to it, or may at least want to be reassured about what is and is not normal Christian belief. So read on.

I was worried that some confused preacher would declare that this eclipse is a special message from God, and now Billy Graham's daughter is doing it. It's related to the "blood moon" nonsense that circulated a few years ago.

People seem to think these eclipses are surprising, unexpected developments, and hence new messages from God. They aren't. Their dates, times, and places have been fixed as long as the sun and moon have been in their orbits. Anyone with accurate knowledge of the orbits could have predicted them. Oppolzer did so in 1887.

Now think for a moment. In a sense, all of nature is a revelation of God; not only every eclipse, but every flower, every blade of grass, every crater on the moon.

But if you start reading ordinary natural events as "signs," you have strayed into superstition. You might as well be reading tea leaves or goats' entrails. Indeed, the "blood moon" people, including Ms. Lotz, get at least some of their interpretation from from medieval Jewish lore (not mainline Jewish doctrine, which, like Christian doctrine, is wary of mistaking outer space for the divine). They don't get it from the Bible.

I want to assure my non-Christian readers that there is nothing in the Bible that tells us eclipses are "signs" or warnings and no Christian tradition of any such belief.

And I want to advise my fellow Christians that if you don't really know what an eclipse is — if you don't realize it is a natural event — then please at least keep quiet and don't confuse other people. Instead of picking up third-hand accounts of other people's speculations, show due respect for God's laws of nature and read and heed, for example, Jeremiah 10:2 and 1 Timothy 4:7 (in context, of course).

2017
August
5

Practicing on the moon

I've tried out my eclipse setup again, Canon 60Da with Canon 300-mm f/4 lens (at f/10), and got good results photographing the moon. Anyone who can take pictures of the moon comparable to these should be well set up to photograph the total eclipse.

Here's the whole picture:

Note: For the eclipse I'm going to rotate the camera 90 degrees so the field extends mostly east-west, since the corona is expected to be bigger in that direction.

Of course, I shrank that picture to fit it on the screen. Here's the image of the moon shown at full resolution, without any sharpening:

And here it is with some digital sharpening (not the full process that I normally use on moon images, but just a little, to show you what's there):

One thing I confirmed is that, even working at f/10, I must focus this Canon lens on a celestial object (which can be the sun through a sun filter). To a first good approximation, the infinity mark seems to be accurate at 75 F, though it changes with temperature as the lens expands and contracts.



My companion during the session

Everybody needs company while observing. This was my companion for the photo session. She forbade me to use the electrical outlet; I used the battery pack instead. But she did me a favor by putting up an enormous mosquito trap. I didn't get any mosquito bites. I hope she ate well.

(iPhone SE, illumination from a high-performance Thrunite penlight that I'll tell you more about later.)

2017
August
1-4

It's eclipse month!


Photo by Joshua L. Jones, used by permission

It's eclipse month! As far as I know, predictions of this solar eclipse were first published by Oppolzer in 1887, so it's not as though we didn't know it was coming. On eclipse day I'll be in Hiawassee with the equipment you see above.

Without further ado, let me answer almost all your questions. Most of this applies no matter where you are, not just Georgia and the Carolinas...

    Click to enlarge or print...


Last-minute eclipse FAQ

(SCROLL UP for much more information.)


Photo by Richard Dasher, used by permission

What is the safest and cheapest way to see the eclipse?

Make a 1/4-inch hole in a piece of paper and look at its shadow a few feet away (as in the picture above). During the partial phases of the eclipse, you will see a crescent instead of a round spot of light.

This method is particularly good with schoolchildren because the teacher can easily see that they are all facing away from the sun.

You can even make a hole with your thumb and forefinger and look at the shadow of your fist.

Is it true that the only safe way to watch the eclipse is on television?

No. That is what the TV networks told their viewers at the 1963 eclipse. It got them lots of viewers, but it wasn't true then and isn't true now. But it frightened a lot of people unnecessarily, especially at the 1976 eclipse in Australia.

Is it dangerous to be outside during the eclipse? Do we need to be careful not to look up?

No; go outside all you want, and look up if you want to, but don't stare at the sun, during the eclipse or at any other time.

The eclipse doesn't make the sun emit "rays" that it wasn't already emitting. That was a widespread misconception at the 1970 eclipse, and it is still circulating.

Sunlight is the same all the time, and the sun will always harm your eyes if you stare at it. But the eclipse makes people want to stare at it. Also, when part of the sun is covered, there is less total glare, and people may not realize that the part that's still visible is still as bright as ever.

Do I need eye protection if the eclipse is only partial?

YES, that is exactly when you need eye protection! During the few minutes that the eclipse is total (if you're in the path of totality), you don't need eye protection because all you see is the dim solar corona. At all other times and places, you see at least part of the bright surface of the sun, and you need protection.

How can I be sure my eclipse glasses or viewers are safe?

I would say, "Look at the ISO safety certification," but someone has been caught printing it on unsafe fake eclipse glasses. So instead I say: Consider the source. Are you getting the glasses from a company or organization that knows where they came from? If so, you're OK. There are many reputable brands and sellers.

So far, unsafe glasses or filters have only turned up briefly on Amazon and eBay; they come from overseas and involve a seller about whom little is known. If you buy from Amazon, make sure the order is fulfilled by Amazon itself or an established dealer, not a third party you've never heard of.

There is one more check. Through safe eclipse glasses, you should see nothing but the sun, and possibly a few bright reflections of the sun, and the filaments of very bright electric lights. If you much of anything else, the filters aren't dark enough. This is not a complete test, but it was enough to detect the unsafe glasses that briefly appeared on Amazon.

How many people's eyes will be damaged by this eclipse?

Eclipses don't blind people by the thousands. In these modern times, injuries happen almost exclusively to people who are intoxicated by drugs or alcohol or are deliberately defying instructions.

My estimate? There will be less than 10 cases of severe, permanent eye damage across the entire United States. Most of the injuries will be temporary, though they may take months to heal.

I don't advise people to take risks — on the contrary, we're safe because we don't take risks. People know what not to do. This study is part of the grounds for my optimism.

We will see.

I'm 30 miles outside the path of totality. Should I travel?

YES, if possible, for two reasons.

(1) A 99% or 99.9% or even 99.99% eclipse isn't enough. You won't see the corona until the sun is at least 99.9999% covered.

(2) The corona is a spectacular sight, and pictures don't do justice to its size or the range of brightness in the delicate streamers.

All I've ever seen are pictures of the corona. On August 21 I hope to see the real thing.


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