How to Photograph a Lunar Eclipse

April 14 Lunar Eclipse Bright CompositePhotographing a Lunar Eclipse is actually not too hard in itself, but will benefit from a bit of planning, particularly for an eclipse time-lapse.

The next full Lunar eclipse in North America is on the evening of September 27th, 2015, then not until 2019! From Denver, CO, the moon will just be starting to rise as it enters eclipse. The east coast will benefit from the moon being higher in the sky, and the west coast will see the moon enter maximum eclipse shortly after moonrise. Since this is one of those rare events, it benefits from some planning to make sure you can get the photograph you want. Here are a couple options and some tips to maximize your pictures.

Quick Snapshots

Snapping a photo of a Lunar eclipse can be as simple as photographing the moon normally. Even a smartphone will work in a pinch, though you’ll also benefit from a camera with a longer lens and a tripod. At maximum eclipse, the moon will dim considerably, meaning a longer exposure time is called for to capture the red glow and lunar surface detail. During an eclipse last year, I found exposures at long as 5 seconds at ISO 400 during maximum worked well, while the same photo with the full moon out of eclipse takes only 1/60th of a second. (Yes, that’s a huge difference in visual magnitude!)

Given that an exposure of a few seconds can be desirable, I highly recommend a tripod, if not a tracking mount, to keep the camera steady. Even a basic point and shoot camera can give you a great eclipse photo. Here’s an example from a few years ago:

Red Moon

This photo was taken Feb 20, 2008 with a Canon A710, a fairly basic zoom point and shoot. 4 seconds at ISO 100. Even basic cameras can give you good results.

Though the Telescope

If you just want to take some individual shots through a telescope at different phases, you really don’t need a tracking mount as long as you keep the exposures short. A tracking mount of course helps you capture great sharp detail. Just make sure you have a wide enough field of view for the whole moon.

Lunar Eclipse Totality

 

The above photo is of the April 14, 2014 eclipse taken with a Canon T3i connected to a Celestron C6 SCT on a CG5 EQ tracking mount. 5 seconds at ISO 400.

Eclipse Time-lapse

If you want to take it up a notch, consider shooting a time-lapse of the eclipse. You’ll want a tracking mount for this, and ideally a moderate focal length telescope. The September 27th eclipse will be a super-moon, meaning the moon is at perigee in it’s orbit, and a few angular minutes larger than average.

Planning your Timelapse

In Denver, the eclipse starts at 7:07pm, reaches max at 8:47, and ends at 10:27pm. See here for additional timing information. That makes the total eclipse duration is 3 hours 20 minutes. Think about how long you want your eclipse time-lapse to be. If you want it to be 60 seconds and 30 frames per second, you’ll need to figure out how frequently you need to take an exposure with a little math.

Duration of eclipse in minutes x 60 / length of movie in seconds x frames per second = exposure frequency

(200 x 60) / (60 x 30) = 6.7

In this case, you’d take an exposure every 6.7 seconds, and a total of 1800 exposures. In practice, you can easily do a time-lapse movie at a lower framerate, say 10 fps, and make this a more reasonable 600 frames, one every 20 seconds. Even a rate of just 2 or 3 frames a second can produce a smooth enough movie given the gradual change.

While I usually advocate capturing images in RAW format, if your goal is to do a time-lapse, it may make more sense to just capture frames as JPEG, since you’ll be down-sampling them for the movie anyway, and you probably won’t want to do much detailed editing on each frame. You’ll also save yourself some hard drive space. Make sure you have a big memory card with plenty of space for the number of exposures you want to capture!

Avoiding the Jitters

The biggest challenge I’ve run into making a time-lapse movie is usually drifting or jitter of the camera, where your target moves a little bit from one exposure to another. This can be caused by tracking error in the mount, or by things getting bumped or shifted, for example if you want to adjust the exposure duration during the sequence, or need to change the battery or memory card in the camera. Some programs will try to re-align the frames for you, but your results may vary, particularly with astronomy related images. So, it’s best to avoid this problem in the first place if you can.

Here’s my first attempt at a time-lapse of a solar eclipse, which looks like the sun is jumping around. This was from adjusting the camera settings manually, and some adjustments to the mount throughout the eclipse. (This was with a solar filter on the scope of course – never point a scope at the sun without an appropriate solar filter!)

In the ideal scenario, you can avoid this problem by:

  • Using a PC to control the camera (so you can do any adjustments to exposure settings as the moon darkens without touching the camera). Setting the camera to auto-exposure may also work, but be warned that many cameras don’t do well in automatic mode with astronomical targets – test it out before hand!
  • Use an auto guider with the mount to keep the tracking accurate over the 3 hour 20 minute period. You can point the guider at a star a little ahead of the moon to keep the moon from washing it out.
  • Power the camera with an external battery or AC adapter. Otherwise you may need to swap the battery mid-way.

Making a Movie

After you capture all those frames for your time-lapse, we get to the hard part of putting them together into a movie. This would be a whole article in itself, so suffice to say that you should go ahead and google time-lapse movie and your preferred movie editor to find a how-to. I built the above solar eclipse movie with iMovie, and doing it for the first time, found it a frustrating experience. Be patient.

Making a Mosaic

In addition, or as an alternative to a time-lapse, you can make a mosaic of the moon at different phases of eclipse. Here’s an example from the April 14. 2014 eclipse. This is much more forgiving of any tracking errors, since you are putting the images together afterwards in photoshop or another image editor. This also allows you to get creative with how you place each image against the others, put them in a circle, across an arc, on a tic-tac-toe board, whatever you think up.

April 14 Lunar Eclipse Bright Composite

Bonus: Moonrise Movie

If you feel really ambitious, particularly for those on the west cost, you can setup some truly amazing effects with a long lens, a moonrise, the right location, some meticulous planning, and probably a bit of luck. This video by Mark Gee is truly magical. If you feel like a challenge, this is it! Details of how he did it on Mark’s website.

In Conclusion

Whether you photograph the September 27th eclipse or not, do go out and enjoy it (weather permitting, of course). It’ll be January 20, 2019 before North America sees the next full lunar eclipse! It’s also a good practice run if you’d like to try a time-lapse before the May 9 Mercury-sun transit next year, or the total solar eclipse on August 21, 2017!

Have questions about shooting the lunar eclipse? Let me know in the comments.

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