It's Never Too Early to Start Planning for an Eclipse

By Ctein

Readers' questions occasionally inspire my columns. A year back, based on a question from Danny Low, I wrote about "Photographing a Supernova," an event that could occur anytime from tomorrow to 100,000 years from now.

A couple of weeks back I got an e-mail from DD-B (David Dyer-Bennet) asking for some advice on photographing the 2017 solar eclipse, whose timing is rather more precisely known and whose path of totality will cross the entire United States from the Pacific Northwest down to the southeast seaboard. It's never too early to start planning ahead for an eclipse, so this column is derived from my reply to his questions.

Do not miss!
Folks, this is a not-to-be-missed opportunity. Anybody who's anywhere on the North American continent should be planning a trip to see this. You really, really shouldn't miss it. You'll just have to take my word for that. I promise that you'll thank me afterwards. There's nothing else like it, and no photograph you've seen has ever done it remote justice, visually or emotionally. Partial eclipses don't count. Partial eclipses are to total eclipses as a McDonald's hamburger is to a filet mignon in a fine French restaurant—entities that theoretically belong to the same class but experientially have nothing at all in common.

A total eclipse is absolutely the most awesome thing I've ever seen. Remember that this is coming from a fellow who's seen a night launch of a Saturn V and stood four meters from red-hot flowing lava. You really may not want to make photographs; you may get a lot more out of the experience just watching. "May" in this case means better than 50% odds, no matter how dedicated a photographer you are.

A total eclipse is mesmerizing.You really may be unable to make photographs. Solar astronomers regularly tells stories about screwing up long-planned experiments the first time they see a total eclipse. Intellectual preparation doesn't work. I knew all of that going to my first total solar eclipse, and I got exactly zero photographs of totality. That was not my intent.

Lots of eclipse-related stuff hasn't been photographed, at least not much nor well. I don't recall seeing a good terrestrial photograph of the lunar shadow on the ground (there are some made by satellites). I don't think anyone has successfully photographed the shadow bands. Those are ripples of light that run quickly across the ground, caused by atmospheric refraction in the very few seconds just before or after totality, when the sun is just a thin slit. I know there are photographs of the landscape by eclipse light. I've got some so-so ones from my first eclipse (I did get photographs, even good photographs...just nothing of totality). The big problem is the same one as including the sun or the moon in a landscape photograph; the luminance range is positively huge. There's enough light. Maybe only 1000th as bright as real sunlight (I don't know, exactly), but much, much brighter than full moonlight. With a moderately high ISO, moderately fast lens, a tripod, and a non-moving landscape, the only real problem is from the exposure range.

Equipment, exposures, etc.
Regarding some of the apparently contradictory recommendations out there for equipment and exposures, not everyone is out to make the same photograph. If you want to capture maximum corona, you're looking at longer exposures although, as these things go, at relatively low magnifications and focal lengths. But, the brightness range from the outermost visible corona to the prominences and chromosphere right around the rim of the sun is easily 10 stops. When I photographed the 1991 eclipse in Baja Mexico, I used Reala 100, because it was the very lowest contrast, longest exposure range film I could find. My best exposure for catching the fullest extent of the corona was one second at ƒ/8 with an 800 mm lens (which produces a solar disk 8mm across). That was on my Pentax 67. That focal length would have been too long for 35mm work; I captured corona out to five solar radii, more than would fit in a 35mm frame. 400–500mm is a lot safer for "full frame" format.

By dint of using color negative film of especially low contrast, I was able to just barely get detail all the way in to the prominences while still holding the outermost corona in my prints (figure 1). Main issue you'll run into when photographing the outer corona with a digital camera is avoiding clipping highlights. (Yes, there are people out there doing some very, very clever single- and multi-image processing on eclipse photographs. Whole different topic; we're not going there this time.)

Fig. 1. You can make an eclipse photo like this...but is that really the best use of your eclipse-watching time? Seriously?

You wouldn't likely need to use that great an exposure. For one thing, in seven years optimal camera ISO is going to be at least 200 and it might be 400. For another, that exposure was pushing into the reciprocity failure region of the film for the dimmest parts of the scene. Not by a lot, but I was losing at least one stop of shadow speed, maybe more.

All told, I'd be surprised if you'll need an exposure longer than 1/4 second atƒ/8 to capture huge amounts of corona. For near-Sun detail, your exposure times would be more like 1/60–1/250 of a second...said with the caveat that the brightness of the corona is not predictable. The near-surface brightness is pretty standardized, but the brightness and clarity of the corona away from the surface not only depends upon the actual coronal activity, which can vary hugely, but also how clear and dark the atmosphere is that day.

Do you need a tracking mount? The sun is moving at 1/14,000 radian/second. If you're using a 500mm lens, that's 1/28th mm/sec in the sensor plane. With a 1-second exposure, that's roughly the "circle of confusion" you'd use for acceptable 35mm work, and I used the same thinking for determining my maximum exposures. The prints look just fine. If you're using 1/4 second, as I'm guessing you would be, that's 1/100 of a millimeter in the sensor plane. That's plenty, plenty sharp!

It's not pixel-level sharp, though, and many of the recommendations you'll read are from people thinking like astronomers. They're trying to figure out how close as they can get to seeing- and diffraction-limited performance. They may also be working at considerable higher magnifications. With decent seeing and a large enough aperture (at least 150mm and preferably 300mm) on a diffraction-limited scope, one should be able to reliably resolve down to better than 1/200,000 radian. That implies relatively short exposures. Hence the potential need for a tracking mount.

But there's a bigger, practical reason for using a tracking mount. It will keep the sun centered in the frame for the entire eclipse! For the serious solar photographer, it's one less thing for them to worry about. Once the camera rig is pointed at the sun, they don't have to keep adjusting it. As I intimated above, the fewer fiddly bits one has to deal with during an eclipse the better the chances of getting decent photographs and enjoying the eclipse.

Watch in awe
Still, my main recommendation would be to go mentally prepared to wind up just watching the most amazing spectacle on all of the planet Earth.

Ctein

Ctein's regular weekly column appears on TOP every Thursday morning.

Featured Comment by Christian Dummer: "I can't but agree on the almost mystic nature of totality. I had the chance to see the Nov. 1994 eclipse in Putre (northern Chile). I was 18 at that time, and still have vivid memories of the enthralling display...in fact, I was so impressed by the experience that I made a resolution to watch the next total eclipse I could.

"So Ctein's timing with this post could not have been better! Right now, I'm only days away from a weekend trip to Easter Island (fortunately just a 5-hour flight away from my hometown, Santiago de Chile) to watch the July 11 eclipse that will be visible in the Southern Pacific and a small portion of Patagonia. Wife's coming along, equipment is all set, and all what's left is hoping for good weather. So thanks for the recommendations, they will certainly come in handy much earlier than 2017!"

Featured Comment by Nathan deGargoyle: "From my sub-teenage memories. It was the late '60's on a Swann's Hellenic Cruise. We were on a tour of Athens and had got to the Theatre of Dionysos. The lecturer had done the usual, got us to sit on the back row then spoke in an ordinary voice to show how good the acoustics were.

"Then he said 'There's an eclipse due in about half an hour. If we stay for it we'll have to miss the museum. Can we take a vote?'

"It came out about 60/40 for staying.

"So we sat in this ancient Greek theatre. Firstly the birds who had been calling loudly went quieter and quieter until there was silence, broken only by the passing traffic noise. Then it started to go dark, like a cloud had moved over the sun. They passed out bits of smoked glass but looking at the sun wasn't the point. I have never had a more eerie experience, all the better for it being totally unexpected (and probably even better still for being age 10.)"

Comments

[Peter]

I'm not sure how a bookmark is going to last 7 years on any machine I use, but this is bookmarked nevertheless.

[OC Garza]

Fascinating, thanks for this post.

[Nick]

I was just wondering the other day when the next chance at seeing a total ecplise in North America was coming. This is perfect; the path of totality runs <1 day drive from any city in which I might conceivably be living, and my son will be 7 years old and able to appreciate it (at least on some level).

If there are clouds that day, I will stab God in the eye with a sharp stick.

[David Anderson]

Also be prepared to be disappointed by the weather as I was in 1999 when I travelled to Cornwall in England.

I ended up just taking a video of how dark it got under the clouds at totality and recording the sounds of the birds as they got confused by the sudden passage of a very short night.

It was also memorable for the thousands of flashes of light that came from point and shoot cameras with auto flash on, that were in the darkness of totality along the headlands that we could see from our position.

[William Schneider]

The late Arnold Gassan, my photo professor in grad school, recommended that I read Annie Dillard's "Teaching a Stone to Talk". I bought the book on his suggestion.

In the book is an essay about watching a total eclipse, and how deeply it affected otherwise rational people. She watched the eclipse from a hillside and observed this:

"People of all the hillsides, including, I think, myself, screamed when the black body of the moon detached from the sky and rolled over the sun. But something else was happening at the same instant, and it was this, I believe, which made us scream."

"The second before the sun went out we saw a wall of dark shadow come speeding as us..."

In the book she continues to explain that the shadow approaches at 1,800 miles per hour, and this huge, speeding wall of darkness prompted an instinctive reaction.

Ever since reading that book, I've wanted to experience a total eclipse for myself. I hope I can make it.

[Roger Bradbury]

@ Ctein: "Folks, this is a not-to-be-missed opportunity"
Listen to the man. It was eleven years ago I saw a total eclipse, in Cornwall. Mere words are not enough. Just go.

[Tom Jones]

After seeing both the 1979 total eclipse in Montana, and the 1991 total eclipse in Baja, I can tell you Ctein is soooo right! I got some decent photos of totality, but I didn't enjoy either one as much as I should have. I was just too busy. Watch the show. Let someone else shoot it!!

[Justin Watt]

There's a "Twilight" joke in there somewhere ;)
http://en.wikipedia.org/wiki/The_Twilight_Saga_%28film_series%29

[John Camp]

My first total was at Minot, ND, sometime back in the 80s, and I agree about the shock and awe aspect. The best way to get really good photos might be not to look at the eclipse. Set up, go through your routine without actually looking at it...eclipses, I sometimes think, might be the real foundation of religions. Something this spectacular, and at the same time so improbable, seems like it must have an intelligence behind it.

JC

[Rob]

Ctein,

thanks for this. I read about the 79 eclipse after the fact, and was sorry I hadn't gone to see it. Now I have ample time to plan for this one. I'll have to start location scouting now.

[Julian]

I have to agree with Ctein - I have only seen one total eclipse, and it is quite simply the most awe inspiring natural phenomenon I have ever seen. I didn't try to take any photos, just stared at the sky and took it all in. If you have the opportunity to see one for the first time you simply must go. But I would leave the camera at home - some things are best seen with your eyes.

[Jamin]

This is not a technical question as you did not go into great technical depth, more of a series of connected synapses firing in remembrance.

What's the name of those nifty gold filters you stuff on top of a lens before burning a hole in the back of the camera? We'll need those in 7 years, right?

[KeithB]

Hmmm, all of these comments make me wonder about the premise of Asimov's "NightFall."

[RawheaD]

My first was the '91 in Hawaii; second was last year's in China. Like everyone's saying Ctein speaks the truth.

My setup for 2017 will be thus: fully automated Celestron CGEM + Megrez 90 + DSLR in auto multi-bracketing mode during the entire totality, and a DSLR (maybe digital MF cam) shooting landscape in full auto multi-bracketing mode during the entire totality.

Me? I'm just gonna stand and stare at the black hole that opens up in the sky, in awe, mouth agape, during the entire totality.

BTW, weather makes and breaks a total solar eclipse. I was extremely lucky to be in the 25% of the big island in '91 that got to see the entire totality without clouds. I was kind of lucky last year that my group had the determination to leave Shanghai the day before the eclipse to a city further west (Wuhan). Wuhan wasn't optimal as it was overcast during totality:

http://www.flickr.com/photos/rawhead/3753141389/
http://www.flickr.com/photos/rawhead/3753998064/in/photostream/

but much better than Shanghai where exactly zero people got to see it at all. More determined people moved even farther west (e.g., to Chongqing) where they got a treat to an unobstructed totality.

I suggest that if you are really determined, then choose an area of the country that will give you the best possible chance of clear skies AND be prepared to drive like mad the night before or even the morning of if your location of choice happens to crap on you.

[John Krumm]

I remember the 79 eclipse in Montana, seen from the playground of my junior high with a bunch of screaming kids. We all had those little boxes but there was a thin cloud cover and everyone just stared at the sun like they weren't supposed to.

[Jeff]

This post should come with a medical disclaimer :)

http://eclipse.gsfc.nasa.gov/SEhelp/safety2.html

[Bruce]

I saw the 1983 Total in Victoria, Australia, and can concur with everything Ctein and others say about the experience. We tape recorded our conversation and it's all just Ooooh's and "Oh my God-WOW!'s" and I haven't see another. Might just try to get to US for this one! My photos were ordinary, but the experience remains. A bit like seeing "Tane Mahuta", the huge Kauri tree in northern New Zealand for the first time.

[Lois Elling]

I was very fortunate to have a dad who was into astronomy and photography and he twice took me with him to see a solar eclipse. I remember the first one best, in 1973 in a small town in the Canadian Northwest Territory called Tuktoyaktuk. It was the most exciting, impressive, and awe-inspiring thing I have ever seen. Even now, 37 years later I can feel some of the emotion and excitement of those few minutes. Thanks for the advance notice. You can bet I'll be watching from somewhere in 2017.

[James McDermott]

Sorry, but as majestic, awe-inspiring and unforgettable as the event will be, I'll still be there with my camera - particularly if the really, really dark bit passes over Stonehenge. Can you imagine the capture - all those nerds formerly called something like Nigel Smith, who'll have given turned their backs on chartered accounting, changed their names to Uther Pendragon, Gorlois or Hengest and turned up in their new white frocks? Priceless. I'll be doing a print sale myself, I expect.

[Carsten S]

If it's not too early to start planning: What dynamic range will 2017's high end digital consumer cameras be able to handle?

[James]

Anyone know of a reliable weather prediction service...? JK.

More seriously, are there total eclipses at more frequent intervals if one is prepared to consider the entire globe? Is there a website that can tell where on earth the next total eclipse will be? I don't live in the US, but split my time between the UK and Australia. From either, it's not too hard to travel to somewhere that may have a total eclipse before 2017.

[Christian Dummer]

@James: "Is there a website that can tell where on earth the next total eclipse will be?"

NASA has a few interesting resources. For example: Five Millenium Catalog of Solar Eclipses, which shows there will be 67 total eclipses during this century. In fact, in Nov 2012 you will have one passing through north Australia.

[ctein]

Dear Carsten,

Best consumer cameras today are around 12.5 stops exposure range. Best professional cameras are around 13.5 stops.

Dunno what it'll be in seven years; don't recall seeing a trend analysis for this characteristic.

pax / Ctein

[jordan retro 1]

If you would convince others, you seem open to conviction yourself. What do you think?