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The moon in total eclipse is very dark, I discovered.
My crop-sensor camera and f/5.6 lens was not up to it.

I saw some "cherry red" photos in feeds, but without technical details.

I used 1/125 second because I earlier learned that the moon is blurry at slower apertures. Without an astronomical tracking mount, the moon is really booking across the view, and a high-speed burst of shots gives different positions of the moon in the frame.

How big of an aperture and how high of an ISO were needed for some successful pictures of the moon in total eclipse, that are not visibly blurred when seen at a 3-inch diameter disk for the moon at reading distance (e.g. a snapshot print or phone screen), taken with dSLR on a normal tripod?

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I bracketed mine between iso 800 - 1600 to be safe. I was using a Canon 650D (crop sensor) with a 55-250mm STM lens on a tripod. My favorite picture ended up being at iso 1600 @ 1/2 second. Since the lens I was using isn't very sharp @ 250mm I figured I could get away with the slow shutter speed. I set my color balance for daylight and cropped in. Going from 5184x3456 to 2657x1772. This was taken in a northern suburb of Minneapolis at 9:16pm CDT. I also did some at iso 3200 but found the dynamic range was not good enough. enter image description here

  • I set my color balance by sampling the post-eclipse full moon, and making that neutral, and applying the setting to all shots. – JDługosz Sep 29 '15 at 6:14
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    Did you mean CST? The clocks are currently reading CDT. I since the glint is on the edge opposite the seas, I think you meant the beginning of totality, or 9:16 CDT. After we "fall back" that corresponds to 8:16 CST. – JDługosz Sep 29 '15 at 6:28
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Lunar Eclipse

I shot the above sequence with settings that varied from:

  • f/4 to f/8
  • 1/2s to 1/160s
  • ISO 400-3200

You are right that the moon is moving quick, but unless you are using a very high focal length lens or planning to view/print the image at a very large size, the blurring may be completely acceptable at speeds significantly slower then 1/125s. In the image example I captured above, the three images at the top of the arc were all captured at 1/2s and at this resolution(and even larger) are sharp enough for me. Considering ISO, you really will want to understand how your camera sensor can handle high values. The Canon 6D I shot these with is quite capable with low light so 3200 can be used if the conditions warrant and the image will not be printed or viewed large. Note that I was using a 200mm lens.

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enter image description here

This was taken yesterday at 10:44 PM EST from Montreal.

What I did is push the shutter-speed until the moon got blurry and then backed up one stop. That was 1/2s. Then I raised the ISO until I got a reasonable exposure while maintaining the maximum F/5.6 stop of the Nikkor AF-S 200-500mm. This gave ISO 1600 which is somewhat noisy on a Nikon D810 but once reduced in size from the maximum 36 MP, looks good.

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Personally, I use an equatorial tracking mount to get images of the eclipse. This allows me to get much deeper exposures than you may otherwise be able to, and at lower ISO settings. The mount tracks in "lunar time", and thus is fairly accurately tracking the moon (there may be some drift, depending on how accurate polar alignment of the mount is.) Here are some examples of my tracked eclipse shots:

enter image description here

enter image description here

enter image description here

enter image description here

You can do the same for solar eclipses as well. Not as necessary if just using a solar film, but with something like a Lunt solar scope where you may be taking long time lapse sequences with an ultra narrow Ha band, you need the ability to track the sun in "solar time" over long periods of time. Here is a shot just with a simple filter:

enter image description here

You can actually get a small portable tracking mount for DSLRs with smaller lenses (up to maybe 400mm, possibly longer with a teleconverter) for a few hundred bucks. The top one I would recommend is the Star Adventurer, but an AstroTrac, SkyTracker or Polari might do in a pinch. You can also pick up a used Orion Sirius equatorial mount for pretty cheap, as little as $750, on AstroMart or CloudyNights Classifieds. With one of these mounts, you wouldn't have to worry about exposure time nearly as much.

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    I specifically asked about exposing it without a tracking mount. Clearly a special astronomical tracker would allow for longer exposures, and I know that. – JDługosz Oct 5 '15 at 6:20
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I used F/4, ISO 1600, and 2 seconds exposure time. The pictures are sharp with my 50 mm lens, but the Moon is small. I took 40 pictures and hope to be able to compile a super resolution image that I could have taken with a 100 mm lens. I then need to deal with the unsharpness that is not yet visible, but will only arise at the super resolution level, including the unsharpness due to the motion of the Moon in the sky. Background stars can be used for this, they are the point spread functions that you get free of charge.

  • You should see this post where I combine multiple shots of the moon shot with a 55mm lens. I detailed notes on the simple PS usage: basically resample larger first, then stack so you get sub-pixel alignment. – JDługosz Sep 29 '15 at 6:04
  • If the moon is 125 pixels in diameter and moves its own width in 120 seconds, in 2 seconds in will smear 2 pixels in that direction. That is, a little less than 1 pixel per second (assuming 20 Megapixels or so). – JDługosz Sep 29 '15 at 6:09
  • @JDługosz That's right, but then the focus was not that perfect, the stars are small blobs about 3 pixels across. – Count Iblis Oct 4 '15 at 23:51

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