This Sunday we will have an opportunity to view a full Lunar Eclipse. If you would like to photograph this celestial event you will need toknow that this event is not as easy as taking a photo of the moon on a normal night. It comes down to your exposure, it will constantly be changing, and youwill need to adjust your camera as the lighting changes. Before going into that, let’s first talk about eclipses and different ways of photographing them.
Types of Lunar Eclipses
Penumbral Lunar Eclipse. This happens when the moon passes through the penumbral shadow of the Earth. These are not that exciting and often you would never even notice them because the moon will slightly dim and they are very subtle.
Partial Lunar Eclipse. This is when the moon passes through the umbral shadow of the Earth. These events are noticeable, and you can easily see them with your unaided eye. Mark your calendar for Nov 7-8 for a partial Lunar Eclipse visible here in St. Louis. It will be a full Lunar Eclipse west of the Rocky Mountains.
Total Lunar Eclipse. This is what will be viewable this Sunday. It is when the entire moon passes through the Earth’s umbral shadow and due to Rayleigh scattering (why the sky is blue) the moon will turn a red or orange color.
As you will see throughout this blog, we will be talking about how the exposure changes through the eclipse and you will need to adjust for this change. You will get different colors due to factors such as clouds,humidity, smoke from the fires out west and where within the shadow the moon falls. These differences will affect your exposure. French astronomer André-Louis Danjon created the Danjon Scale, five values of brightness.
Using the Danjon scale we can extrapolate form Mr. Fred Espenak’s Lunar Eclipse Exposure Guide to get these exposure guidelines.
When picking your exposure, you must consider your equipment. A longer lens will show motion blur at a higher shutter speed than a wide-angle lens. A newer camera will perform better at a higher ISO than an older camera. Some lenses will not be as sharp at f2.8 and will need to be set at f/5.6 to get a sharp image. This is where knowing and using your equipment,testing and planning will all help you in getting your best shot.
Different Ways to Capture the Lunar Eclipse
A total Lunar Eclipse will take a few hours (see time table for the St. Louis area bellow) which will give you plenty of time to shoot. But before you start you will want to figure out how you would like to capture the eclipse and what your final image will look like. So let’s go over a few options starting with which lens to use.
A wide-angle lens will allow you to include some foreground and or capture the whole event as a multi exposure or Star Trail.
A close-up of the moon where it dominates the frame. You can composite a few of these into one image to show the different phases of the eclipse.
One wide-angle long exposure of the night sky that allows the stars to trail. Tricky to show the eclipse.
Using post production software like Photoshop to combine different photos of the eclipse to show the different phases
Each of these styles will give you different looks and the multi exposure/composite will be a combination the first three. Before shooting you really want to plan out which you want to do. Planning is the key to all of these. Checking the weather (as of right now, St. Louis will be partly cloudy),scouting the location to line up the shot and make sure it will work. Making sure you have the right gear…
1. A good Tripod is a MUST!
2. Turn off image stabilization (really a good ideal whenever using a tripod and long exposures)
3. On DSLR’s lock the mirror is the up position to reduce vibrations.
4. Bring extra batteries and make sure they are all fully charged. The Lunar Eclipse will last over a few hours.
5. If you plan on bracketing or taking a lot of photos make sure you have a large enough and empty memory card. It’s a good practice to always have a spare in the bag.
6. You can use your auto focus when the moon is bright, but once you have a good focus, turn off your auto focus because as the moon gets darker your camera may hunt for focus
7. Bracket your exposures. Try different times and ISOs. You will have time so make sure you get the best exposure for your system. Each camera and lens setup will perform a little different. My R6 will allow me to use a higher ISO and still look good unlike my older 5DMkIV. Newer cameras have better low light performance.
8. Bring a lawn chair and friends
Tips for Telephoto & Telescopes
1. Choose the right focal length and make sure your shutter speed is correct for that length. In Astrophotography we often use the500 rule. 500 divided by focal length to get a good shutter speed. That is for stars. The moon is also moving so I would probably use 200 divided my focal length. Ideally, go out a night or two before and take some test shots to findout the slowest shutter speed you can use without getting motion blur.
2. At the darkest point, you will need a long exposure.If you have a star tracker (a head that rotates and counters the earth’s rotation) us it but make sure you have it set for tracking the moon. It is a different setting that for stars and Milky Way tracking.
3. Set your meter for spot metering and make sure it is on the moon. Again, when it gets dark, watch your shutter speed
4. Bracket, bracket, bracket.
Tips for Wide-Angle
1. Location planning is going to be the most important aspect for wide-angle shooting. You want to check out the location beforehand to make sure you can capture the whole event without the moon going behind a tree or building. Find an interesting foreground and do some scouting.
2. The moon rises about 50 minutes later each day.Check the timetable and then go to your location and make sure it will work.You can also use some apps like PhotoPill or Stellarium that will allow you to go to a location and adjust the time so you can see the path of the moon on your phone. I use these apps a lot in all my night photography
3. We are forecast to have a mostly clear night.That means there may be some clouds. Take a lot of photos then you can edit if needed to make your final image.
4. Your light meter will lie to you even on spot metering. With wide-angle lenses your light meter is not going to help much. Bracket,bracket, bracket, and bracket some more. You do not want to overexpose the moon which is a typical issue when using a wide-angle lens and shooting the moon.
Tips for Lunar Star Trails
1. This will be the hardest and will need the most planning. Once you start a star trail shot you really don’t want to change your exposure, but you will need to in order to capture the moon and make sure it is sharp.
2. Plan your start and end exposure to capture the time of eclipse in single frame. Also, consider the length of trails you want to see. I normally prefer around 5 hours. Shorter trails are not as cool, but that will be your personal preference.
I have never tried this style and would probably shoot it with two cameras. One set up just for star trails, the second on to capture the eclipse
Tips for Multi Exposure and Compositing
My preferred style
1. Decide on a great foreground if you are planning to use wide-angle and do your planning. For telephoto, use the longest lens you have and can use without getting star trail and keep the moon centered (or as close as you can)
2. During the eclipse take a photo at regular intervals and keep that interval the whole time. I recommend a shorter interval, so you get more images. This way if you miss one or two because a cloud moves through, you will have some close to what you want.
3. Shoot short intervals will also allow you to make a time laps video if you are so inclined.
4. As with all styles, be ready to adjust your exposure. Depending on your final vision, you may want to allow the moon to get a little darker as it inters full eclipse, so it looks more natural.
Here is the timetable for Sunday at St. Louis.