I've never been a big fan of astronomical events: there are just too many meteor showers or planet transits to keep up with, and a slightly larger Moon just doesn't do much for me. But I have completely shed my cynical attitude regarding the upcoming total solar eclipse. The more I learn about it, the more excited I am to see it — and to photograph it. I'll be heading down to Nashville, which lies in the path of the eclipse's shadow, so I'll have the opportunity to get an incredible snapshot of the Sun completely covered by the Moon.
I consider myself an amateur photographer, but I’ve never tried taking pictures of celestial events before, and I’ve never even witnessed an eclipse. So I turned to a self-proclaimed astrophotographer Justin Starr to give me some tips about how to best snap a picture of the Sun — before, during, and after totality. Watch his demonstration in the video above and check out a summary of his suggestions below.
What you need
When it comes to setting all of your gear up, you’re going to need a pair of solar filter glasses. These are specialized lenses that block out 99.99 percent of the Sun’s light. You’ll need to wear them in order to spot the Sun in the sky and also to watch as the Moon starts to cover the solar disc. NASA and the American Astronomical Society have a list of approved manufacturers of solar filter glasses on their sites.
Once your eyes are safe, there are four basic things you’re going to want to use to photograph the eclipse:
- A DSLR camera or a camera with full manual controls
- A telephoto lens (we’re using a 70 to 200 millimeter zoom lens)
- A tripod
- A solar filter for your lens
Just as your eyes need protection, so does your camera lens. That’s where the solar filter comes in. These specialized instruments are made to fit over your camera’s lens to block out most of the sunlight. Most of the filters will turn the Sun into a golden or orange disc in your photographs. And you’ll need to be sure that your filter will properly screw on to the front of your lens.
Once your lens is fitted with a filter, set up your camera on your tripod and aim it toward the sky. You may need to spend a few minutes searching for the Sun, which will be tricky with the solar filter, as it blocks out basically everything else but the Sun. And no, you don’t want to take the filter off leading up to and after the eclipse. “If I did not have a solar filter on here, I could really fry the imaging sensor on my camera,” Starr told me during a demonstration. Even when 5 percent of the Sun’s light is left, it’s enough to do some damage.
With the Sun in your camera’s sights, you’ll need to make slight adjustments throughout the length of the eclipse. For one thing, you’ll have to periodically adjust the position of your camera and tripod to account for the Earth’s rotation and the Sun’s movement across the sky.
And of course, you’ll need to slightly adjust your camera’s settings over time. When shooting on manual, the three main settings you’ll need to worry about are your aperture, your exposure time, and your ISO. Aperture refers to the size of the hole in the lens that’s letting light into your camera. If you’re using a telescope to photograph the eclipse, your aperture will likely be fixed. For telephoto lenses, you can adjust the aperture yourself, but you’ll likely want to keep it fairly wide open throughout the duration of the eclipse. (Reminder: smaller numbers like f2.8 mean bigger, wider apertures.)
The exposure time refers to how long your camera’s shutter is open, which dictates how long your camera’s imaging sensor is exposed to light. When the Sun is barely covered, the exposure time will be pretty short since it won’t take a lot of time for light to fall on your sensor. That will change throughout the eclipse, though. “As the Moon begins to occult the Sun more and more, you will need to lengthen the exposure a little bit,” Starr says. “And that will be a gradual process, over the course [of the eclipse]. So you want to be checking your camera and your settings as it goes.”
The final setting to worry about is ISO, which refers to how sensitive your camera’s imaging sensor is to the light you’re letting in. The higher the ISO setting, the more sensitive your imaging sensor is to light. That can increase the brightness of a photograph, but it also increases the amount of noise, or graininess, on your pictures. Photographers usually try to keep the ISO number low to decrease the amount of noise in their images. When the Sun is still super bright, you won’t need a very high ISO. As the eclipse happens, though, you may need to raise the ISO to capture detail in the darkness.
Now, for those in the path of totality — where the Moon will completely cover the Sun — there is a brief time when you can take pictures without the solar filter. That time, of course, is totality. Take off your filter and snap some precious pictures. (Some filters, like ND filters, can also be rotated to let more light in instead of taking them off.) This is the only part of the event where you’ll be able to see the Sun’s atmosphere or corona, which is overpowered by sunlight at all other times. It’s going to be pretty dark during this time, so you may have to increase your exposure time and ISO.
But remember, you only have a few minutes before the Moon starts to move away again. Try to get as many pictures as you can, but also take off your glasses and see the sight for yourself.
Now, for those who don’t have fancy equipment to use, snapping an image with your smartphone is an option. NASA says taking a picture of the Sun directly with your smartphone probably won’t damage the lens, since the lens is probably too small. The problem with using a smartphone, though, is quality. The Sun will be very far away in your frame, and focusing on the solar disc will likely result in a bright, glaring blob in the sky.
An option is to put a solar filter over the lens when the Sun is mostly covered up by the Moon. That won’t get rid of the zoom problem, so if you want to upgrade things a bit, you can get a telephoto lens that attaches to your phone. Set your smartphone up on a small tripod, and place a solar filter over that lens to get the picture you want.
I may attempt a few photos with my phone, but my main focus will be the DSLR. And now with all these tips in mind, I feel fairly confident about getting a good shot on the 21st. Some other things I’ll be bringing with me include a blanket and sunscreen to shield from the Sun, even though it’s disappearing. Starr said I should also practice shooting the Sun a few times before I put my skills to the test during the eclipse, so now my weekend plans are set. Check back here after the eclipse to see how my photos turn out.