 For the first time in 99 years, on August 21st, a total solar eclipse will pass over the United States from coast to coast. And it's going to be an amazing sight to see. And also, an amazing sight to photograph. Here's how I'm prepping for this celestial event, and a few things you need to know about photographing the sun. For starters, what is an eclipse and why is it so rare? Well, it's a serendipitous alignment of the Earth, the Sun, and the Moon. On every 18 months or so, the Moon passes directly between the Earth and the Sun on its orbit. And those in the direct path of the Moon's shadow, called the path of totality, will see the Sun completely covered up by the Moon. If you're in this path, the eclipse will last about 3 hours, from when it starts to become obscured to when it's fully visible again. Don't worry, even if you're not in the path of totality, the length of the eclipse will vary, but basically anyone in the continental US is going to see the Sun mostly covered. Now, if you're going to be watching this, remember that staring at the Sun is bad for your eyes, even during an eclipse, so you'll want to get a pair of solar filter glasses. These aren't like your regular sunglasses, though. These glasses block over 99.99% of the Sun's light, so all you'll see is either an orange or white disc in the sky. NASA and the American Astronomical Society have lists of approved manufacturers that sell standard solar eclipse glasses if you still need a pair. Now, you're going to want to get a picture of this, and your phone might not cut it if you're looking to get a jaw-dropping shot. You'll probably need to manually focus, and if you zoom, you'll be sacrificing a lot of quality. You're going to risk some blur, some noise, and you'll notice the Sun is still pretty far away in the frame. Other than buying specific telephoto lenses for your phone, this is likely the best you'll be able to do. So if you have a DSLR, it's definitely time to break that out. We talked with Justin Starr, an amateur astrophotographer, about what to expect and how to get a perfect shot. We have three key pieces, which is our telescope, our camera, and the solar filter. Correct. Just like your eyes need a solar filter, so does your camera. If I did not have a solar filter on here, I could really fry the imaging sensor on my camera. Justin is using a telescope here, but we'll be using a 70-200mm with a two-times converter, which should get us close enough. Then you'll need a solar filter to go on top of your lens. Now you want to make sure that your solar filter is threaded properly for your lens. Basically, do they match together? Plus a tripod in order to keep the camera steady and focused on the Sun. With all this equipment, here's what you need to know. In any photograph, there are three things you have control over. You have your aperture, you have your exposure, and you have your ISO. The aperture is the size of the opening that's letting light in. If you are using a telescope, chances are that your aperture is fixed. To compare this to a camera lens, this would be a 400mm because it's a 400mm focal length. This is at f5. I have no control over that. It is what it is. I have the camera currently set at 1.125th of a second exposure. That means that the shutter is going to be open for 1.125th of a second. Very quick because we don't need that much time. We're looking at the Sun. Even with 99.9% of its light being blocked by my solar filter, it's still pretty bright. Yeah, exactly. And what is ISO again? One way you can describe it, I think of it like gain on an amplifier because I'm a musician and a guitar player. You'll get more volume, more signal, more brightness if you turn the gain up, but you're also going to introduce some noise. Ideally, you want it to be as low as possible. Once you have your camera set up and focused on the Sun, you'll want to fire off a few test shots to make sure your settings are as you want them to be. When the eclipse reaches totality, the uneven lunar surface causes beads of light to pop out from behind the Moon. Those are called Bailey's Beads, and they're a result of the Moon not being perfectly round. As this is happening, you're going to have to adjust your camera settings to make up for the drastic changes in light. So you want to be checking your camera and your settings as it goes. 1.60th, that's 1.60th of a second might be good as it's getting really dark. Gotcha. And when you reach total totality, you can even take the solar filter off and photograph the corona. I'm not sure I'm ready for that. That's the Sun's atmosphere that we usually can't see because it's way too bright. It looks like delicate threads of light emanating from the solar disk. You will not capture the corona with the solar filter on. It's not that bright. I gotta do it then. You gotta do it. Yeah, that's the thing to remember. If you are in the path of the total solar eclipse, you definitely want to take your glasses off for those two and a half precious minutes of totality. It's the only time of the eclipse you'll be able to see with your own two eyes. This is also the only time you can photograph the sun without your solar filter and get that perfect shot of the corona. As the moon starts to reveal the sun again, you'll want to make sure to put your glasses back on as well as your solar filter to get the shots that you need. And remember to adjust your settings as necessary. As things get brighter, you'll want to speed up your shutter and close your aperture or lower your ISO again. As for me, I've got my camera and my lens. I'm using a Canon 5D with a 2x converter and a 70-200mm lens. My solar filter is on the way. I'll be heading down to Nashville along with the rest of the world to see if I can get an awesome shot. Let's hope I don't mess this up. Got more questions about the total solar eclipse? Check out our explainer linked in the description below. Also we'll be rolling out more coverage as we get closer to the eclipse on the 21st, so be sure to visit TheVerge.com to learn more about this celestial event.