Lunar Eclipse Photography Tips

Here are some pointers to help you capture great close-up photos.

Seronik - 2007 lunar eclipse

This image of the August 2007 lunar eclipse was captured with an 8-inch telescope and a Nikon D200 DSLR camera. The exposure was 5 seconds at ISO 800. Courtesy Gary Seronik

If you have a digital SLR (DSLR) or 35mm SLR film camera and a telescope with a motorized tracking mount, you can employ prime-focus photography to get a lunar-eclipse image like the one shown above. Here’s how it’s done.

Telescope Specifics

The ideal telescope is one with a focal length that allows the Moon’s disc to very nearly fill the short axis of a 35mm film frame. For a “full frame” DSLR or 35mm film camera, something around 2,200 millimetres is nearly perfect. That means an 8-inch scope working at f/11, or a 10-inch f/9. If your DSLR has a “cropped” or “APS-C sized” sensor (as most do), then a telescope with a 1,500 mm focal length fits the bill. An 8-inch f/7 or 10-inch f/6 is a good choice.

For the photographs shown here, I used a home-built 8-inch f/4.5 Newtonian with a focal length of around 820 mm. The image scale was a bit small, so I attached a 1.5× teleconverter to my camera, which boosted the effective focal length up to 1,370 mm.

If your telescope’s focal length is less than ideal, do your best working with you have. You can still get pleasing results but you may have to crop your photos a bit to compensate for the smaller image scale.

Adaptation

To attach a DSLR camera at the prime-focus of a telescope, you need a T-ring (left) and a prime-focus adapter tube.

To attach a DSLR camera at the prime-focus of a telescope, you need a T-ring (left) and a prime-focus adapter tube.

For photography with your telescope, you need two extra pieces. First, a T-ring-adapter for your specific make of camera. This is a simple fitting with female T-threads in front and a bayonet flange on the rear to match your camera’s lens mount. T-rings are available for most popular camera brands and models. You’ll also need a prime-focus adapter tube. This piece screws into the T-ring and allows you to attach your camera to your telescope’s focuser.

Exposure Time

Depending on the specifics of your camera and telescope combination, and the brightness of the eclipsed Moon, the optimum exposure time will vary considerably. Expect your exposure to be several seconds long, depending on the ISO setting you’ve chosen. That’s why you will most likely need a motorized mount capable of tracking the Moon to prevent the image from blurring during the exposure.

Seronik - Lunar eclipse pairing.

As this pair of images demonstrate, the brightness and colour of the eclipsed Moon can vary considerably. You will have to compensate by using different exposure times.
Courtesy Gary Seronik

ISO Setting

DSLRs have improved greatly in the past few years, so if your camera is of recent vintage, you can probably use ISO 1600 or greater without fear of introducing a lot of image noise. Older cameras will likely need to stay at ISO 800 or lower.  As you increase the ISO, you can reduce the exposure time, and vice versa.

White Balance

Set your camera for daylight white balance (usually a Sun symbol on your camera’s menu display). “Auto,” or any other setting, will give your images an unnatural colour cast.

Vibration Control

Firing your camera’s shutter is likely to introduce image-blurring vibration. If your camera is equipped with a mirror lock-up feature or exposure delay mode, here’s where it comes in handy. In any case, you want to be sure to use a remote shutter release if you have one.

If your camera lacks these features, here’s a handy trick. Get a piece of black cardboard bigger than the front opening on your telescope. Set your camera’s shutter speed for one or two seconds longer than required for the correct exposure. Hold the card in front of the scope so that no light makes its way down the tube. Now, fire the shutter and wait a second or two for vibrations to die out, then move the card out of the way to begin your exposure.

Experimentation is Key

Seronik - Feb 20 Eclipse triptych-r

This trio of images from the February 20, 2008, eclipse shows the Moon’s passage through the umbra, the darkest part of the Earth’s shadow.
Courtesy Gary Seronik

Fortunately, a lunar eclipse lasts for a long time — photographing one is nowhere near as frantic as with a solar eclipse. That means you have time to try different exposure and ISO combinations until you find the one that works best for your set up. How will you know if your exposure is correct? The most reliable way is to check your camera’s histogram display — especially the graph that corresponds to the camera sensor’s red channel. Watch for “clipping” — the histogram data crowding up against the right side of the graph.

Finally, to maximize your chances for success, it’s a good idea to setup your gear a night or two before the eclipse and perform a dry run session photographing the Moon. There’s nothing like actually going through the entire process to ensure that your gear is working properly and that you know how to use it.

And if you get a good eclipse photo, please share it with us.

Categories: How To, Moon and Planets

We welcome your astronomical photos and observations and your comments on the new expanded SkyNews website. Please send to: editor@skynews.ca

8 comments on “Lunar Eclipse Photography Tips
  1. I’ll give it a try and let you know how it goes. Thank you!

  2. Bill Campbell says:

    Hi
    Any tips at all if one does not have a motorized tracking telescope? Mine is a 10 inch push and nudge Dob.
    Thanks for any advice.
    Bill

    • Gary says:

      Hi Bill:

      Crank up the ISO on your camera and try to keep exposures as short as possible. Of course, you can enjoy the eclipse by just viewing.

      Good luck!
      Gary

  3. John Thiel says:

    This isn’t the only way to do it. In fact you could really do the exact opposite and still get perfect results, or maybe even better.

    FAIRLY EQUIPPED ASTRONOMER, WITH A POINT AND SHOOT CAMERA: If you have any kind of telescope and can fit the Moon in the eyepiece, then you can take any point and shoot and get a great, sharp shot right through the viewfinder. It may take you several shots to get it right handheld, but the result even on full auto should be impressive. The key is to make sure the light from the Moon is being metered, not the dark night sky.

    DECENTLY EQUIPPED PHOTOGRAPHER, WITH NO TELESCOPE: If you have a DSLR and a decent telephoto lens, or even a point and shoot capable of manual settings and a decent optical telephoto range, you can do it handheld or with a tripod.

    It’s dark outside, but it’s always a clear, sunny day on the Moon. So what should our settings be for a bright sunny day? ISO 100 or 200 with a fairly fast shutter speed–1/60 or 1/125, not a time exposure. Since this is an eclipse, try the 200, 1/60 first with about f8 and experiment from there. Make sure you get the Moon in focus.

    SMART PHONES: No matter how many megapixels your smart phone has, the lens on it is a teeny-tiny little thing. Generally cameras see better than your eyes, but in the case of smart phone cameras your eyes are much better. No matter what you do, the Moon or any other bright object is going to be a glowing blob. The only answer here is to get a real camera.

    • Gary says:

      Thanks John:

      No, the article doesn’t describe the “only” way to photograph the Moon — it only describes the “prime-focus” method, which is how I got the photos used to illustrate the piece. The article in the March/April issue of SkyNews talks about a few more and you mention some good alternatives as well.

      Gary

  4. Dave Collins says:

    I’ve been taking some shots with an iPhone using a gadget that clamps it on an eyepiece. Most shots suffer from either over or under exposure. Do you know if there is an app which will allow variable shutter times?

    thanks

    Dave Collins

  5. Steve Irvine says:

    Just a reminder that the beautiful star, Spica will be nearby the Moon during the eclipse, so a slightly wider field photo than suggested above with the prime focus might have some potential as a nice image of the two. A 200mm lens on a DSLR is a possibility. Mars will be about 9 deg. away from the Moon, and might make an interesting colour contrast with the eclipsed Moon. Perhaps a 100mm lens in this case to include the Moon, Spica and Mars. As mentioned, a tracking mount will give the best results. Good luck everyone!

  6. Mark Schell says:

    Hi Gary, great article. I have to agree with John Thiel; I took some photo’s of the Dec. 21, 2010 eclipse with a Fujifilm 12MP P&S. Not as good as the ones you took, but passable. This year I received the best X-mas present, a Canon Rebel T3. Old by some standards, but I love it. I ordered the adapters for hooking my camera up to my Skywatcher 8″ dob. If the weather co-operates, I want to try both cameras, simply to see the difference and guarantee at least one shot turns out.
    I would also like to mention that yourself, Alan and Terence have been very inspirational to me. I can’t thank you all enough.

    Regards,
    Mark.

Khan Scope
Canadian Telescopes
Vixen Optics
Jasper Dark Sky Fest
Lennox and Addington County Dark Sky Area
Starfest 2014
North Frontenac Township Dark Sky Site
Hubble\\\\\\\
Backyard Astronomer\\\