While a lunar eclipse isn’t nearly as rare as a solar eclipse, it is still an event to take note of. The last time I was able to photograph this phenomena was 14 years ago! As I write this post, the next one is about a month away and as I started to prepare I thought I would write a post on what it takes to image the moon during an eclipse.
The first thing to realize is that the moon is moving across the sky. To the naked eye it doesn’t seem so but to image the moon you will need to use a telescope mount that will track the moon. In general, you can image the moon without a mount because it is bright enough to allow for very short exposures. During the eclipse the moon is very dim in comparison and will require longer exposures. (Don’t be discouraged if you don’t have a mount. Read the last paragraph in this post.)
Next we need to work on what lens to use. I created a sample FOV using “The Sky X” to show what the image size would look like using a 300mm lens with a DSLR (Nikon D300 in my case).
As you can see, the moon is pretty small in the field of view and I would say a 300mm lens is probably the smallest I would use.
As far as an imager, pretty much any DSLR (or film SLR) will do. I had pretty good luck shooting with E100s slide film when I last imaged a lunar eclipse. For this go around I will be switching out my SBIG ST-8300M for my Nikon D300. I am doing this because the SBIG camera is a black and white chip only and is designed for much longer exposures. The Nikon is color and will be fine for imaging at the exposure lengths needed.
The strategy I use when imaging the lunar eclipse will be a bit different this time. I was limited a bit by film last time because there are only a limited number of shots per roll. With my D300 and a few 32GB memory cards, I can shoot constantly this time without worrying about running out of space. This event progresses pretty slowly compared to a solar eclipse so you really can take your time and shoot a ton of images. Bracket your shots, taking multiple shots at every setting. Change exposure time, f-stop (if using a camera lens) and even ISO settings. Don’t skip imaging the phases. It is a good way to warm up to the totality and you can create nice mosaics with the images. I would also recommend getting out once or twice before the eclipse. It is good to work the bugs out while you still have time to correct any issues.
Please don’t be discouraged if you lack any of the equipment listed above. If I had none of it, I would still be out viewing the event and I encourage you to do the same as it is an incredible sight. While you are out there, use whatever you have to image. Try a shorter lens at f2.8 and a tripod. Try a video camera with digital zoom. Even if none of it comes out perfect, you will have learned and participated in one of the grand celestial events.
Good luck and clear skies!