Viewing & Photographing Comet ISON

You ready to photograph the most spectacular comet in Earth’s history? Me too, but unfortunately, I don’t have a clue when such a comet might show itself.

What about Comet ISON? Soon after it was discovered about a year ago, some folks were calling it the “Comet of the Century” and saying it would be as bright as the full moon. It sure got my attention.

Illustration courtesy of Sky & Telescope

(Thanks to Sky & Telescope and Astronomy for providing much of the viewing info presented here. And thanks to Tim Williams for clarifying a few things.)

I’ve never had a ticket to ride the hype bandwagon, so before I got my hopes up, I did a little research. I’m neither an astronomer nor a prophet. Everything I know about Comet ISON comes from folks who are a lot smarter than I am. The first thing I learned from them is that nobody can say for certain how bright the comet will be.

Comet ISON is visible now in telescopes, and it may become visible to the unaided eye by the end of October or early November. But don’t count on it. More likely, it will be sometime in mid-November before you can see it with the naked eye, and even that’s not certain. Recent predictions do not bode well for those of us anxious to view and photograph our first great comet.

Perihelion, when the comet comes closest to the Sun, occurs on November 28. The closer a comet is to the Sun, the brighter it shines because the Sun illuminates the ice and dust in the comet’s coma and tail. For ISON, the optimal viewing period should be about the last 10 days of November and the first 10 days of December, with the days immediately around the perihelion being the best.

Over the next several weeks, we’ll learn a lot more about how bright ISON’s going to become. But even if it shines far less brightly than the early predictions, it should still put on a good show. Remember Comet Pan-STARRS this past spring? How many of you failed to see it with the naked eye, as I did? I couldn’t see Pan-STARRS, but the rascal still showed up in my photos. That’s the beauty of using digital cameras with high ISO’s and big apertures. Even in wide-field views, faint objects can show up surprisingly well in photos.

Binoculars can make your experience much more enjoyable. Besides improving the overall view, they might prove valuable in helping you find the comet. It won’t make any difference whether or not your camera can “see” the comet better than you can if you don’t point it in the right place.

When and Where to See Comet ISON

On the first of November, Comet ISON rises about 4 hours before sunrise and by the middle of the month about 3 hours before the sun. Look for it in the east-northeast sky. Predictions are for the comet to brighten to naked-eye visibility by the middle of the month, but, again, no one knows for certain what it will do. The moon won’t be a factor during the first 2 weeks of November, as it rises and sets outside of the comet-viewing period. On November 1, a very thin crescent moon shines in the sky with ISON.

From the middle of November until perihelion on the 28th, ISON rises later each morning. On the 26th, it rises in a twilight sky about 40 minutes before sunrise and will be very difficult to see. The comet will not be visible on the 27th. On the 28th, it rises 2 minutes before sunrise and will be too close to the sun to see without specialized viewing gear. It will not be visible on the 29th. From November 29 forward, ISON rises earlier each night. Beginning December 27, it shines all night, but who knows if it will be visible to the unaided eye that far away from the perihelion.

Mornings Not To Miss

To make the most of this opportunity, you should get out every morning that you are able from mid-November through the third week of December, although you shouldn’t get your hopes up for any good November viewing and you can safely sleep in on November 26 through the 29th. If you have to choose only a few mornings, try from about December 5 to the 15th.

While the comet will be brighter in the days closest to perihelion, it also will be shining in a brighter sky because it won’t rise until closer to sunrise. For the best photos and viewing, you might find it preferable to shoot when the comet is shining in the darker dawn sky, when there is more contrast between it and the sky. Even though the brightness of the comet will be lower, it should show up better and you get the benefit of the twilight sky colors as a backdrop. On November 30, ISON rises 26 minutes before the sun in an already bright sky and close to the sun. It rises earlier each night, and by December 14 it rises about 3 hours before the sun. If ISON turns out not to be very bright, those mornings when it rises before twilight will offer the best chances for photos.

The full moon occurs on November 17 and will be shining all night. From that morning until December 1, the moon will be in the morning sky when the comet is visible. (The moon won’t be in the same field of view with the comet except during its crescent phase leading up to the new moon on December 2.) The Leonid meteor shower also peaks the morning of the 17th, but the moon will drown out all but the brightest meteors. It won’t do any favors for ISON, either, but at least they’ll be on opposite sides of the horizon.

What else will be in the sky with Comet ISON?

Mercury will become visible in the eastern sky around November 9th, shining at about magnitude +0.8. It brightens to -0.7 around the 20th and remains this bright into December. Saturn shines at about magnitude +0.6 during the last week of November and into December. Look for it below Mercury up until the 26th, when the two planets come very close together and switch places, with Saturn rising above Mercury. The crescent moon shines in the dawn sky with ISON from November 28 until December 1. On November 17 and 18, ISON passes very close to the bright star Spica, shining at magnitude +1. Reddish Mars shines at about magnitude 1.3. And if one comet isn’t enough for you, during the first half of November, Comet 2P/Encke may be visible to the unaided eye. It rises in the east about 2 hours before sunrise. If both it and Comet ISON achieve naked-eye visibility at the same time, you can easily tell them apart because ISON will be the one highest in the sky.

Photographing Comet ISON

For wide-field photographers—those who are using lens focal lengths ranging from wide-angle to 300mm—the most important thing to understand about photographing comets is that they are like any other night-sky subject. Composition, exposure, and general technique will be the same that you’d use for the moon, planets, or any other bright object in the night or twilight sky.

Cameras for Comets

In a few weeks, people all over the country will be photographing ISON with everything from massive telescopes to cell phones. With some photo subjects, the kind of camera you use is not as important as your technique and compositional creativity. With many night subjects, however, the camera you use is very important. With comets, it can mean the difference between getting a great shot and simply getting a shot at all.

Unfortunately, cell phones and other point-and-shoot cameras are not well suited to shooting comets in the night sky because they don’t allow the high ISO’s and big apertures that you need to capture the comet. Try shooting at ISO 1600 with a point-and-shoot, if that option is even available, and all you’ll capture is a bunch of noise. Understand that I’m talking about shooting the comet in the night sky full of stars. When the comet is in a twilight sky, you can use lower ISO’s and a point-and-shoot camera can work okay.

If you want to capture the comet up close and personal, you’ll need to use a telescope, or at least a very long telephoto lens. I’m not going to talk about photographing through telescopes here. I prefer wide-field night photography, using DSLR cameras and lenses ranging from fisheye to around 300mm. That’s what you need for photographing comets when you want to show something else in the image.

Some Stuff You Really Need

I hope I don’t have to tell you that you need to shoot from a tripod. I do? You mean you don’t like tripods? Well, tough. Get used to it. If you want to make the best photos of subjects like comets, or most any night photography for that matter, you need to use a tripod. No excuses. But I’m not going to try to force a tripod on you. Frankly, I hope you don’t use one, and I wish no one else did either. That way, I’d be the only photographer in the world to have sharp photos of Comet ISON.

It’s also a good idea to use a cable or remote shutter release so you don’t jiggle the camera when you press the shutter. And at the same time, you should employ some sort of mirror lock up so the camera doesn’t vibrate from mirror slap. Many cameras have a “Mirror-Up” feature, which I like. You can also use a delayed shutter, usually set in the camera’s menu, or you can use the self-timer.

Check out this post for information about focusing in the dark.

Where To See It

The first section of this article explains where and when to look to see Comet ISON. During the prime viewing period of late November and early December, ISON will be a morning comet, low on the east-southeast horizon. You’ll need an unobstructed view, so if you live in a mountainous region, get high up, so no mountains are blocking the view. In a city, any building will block the comet unless it is far away from you.

Because the comet will be low on the horizon, it will be competing with both twilight and any light pollution from cities. The best location will be one far from city lights. Also, think about how local weather phenomena might affect the view. For instance, you might think that a great viewing site would be on the coast, looking out over the ocean. That might be the case in some areas, but if your coast is anything like mine here in North Carolina, there could be a low band of moisture on the horizon that could block the comet entirely.
Lens Choice And Composition

You can photograph Comet ISON with everything from a fisheye lens to a telephoto. I’ll probably be using lenses ranging from about 14mm to 300mm. Longer lenses will make the comet show up better, for sure, but if all you capture in the photo is the comet, the image will lack any excitement—there will be nothing about to separate it from any number of other shots. If you want your images to be unique and have some pop, you need to compose the comet as a complementing element in the scene. It can be the main attraction, say, by using a 300mm lens and isolating the comet against a distant mountain range, or paired up with the crescent moon, or it can be just a small complementing event in a wide-angle scene.

The real key to making a good photo of ISON is the same as with shooting many other small objects in the sky. You want to compose a photo that would look good WITHOUT the comet. The comet, while being our main focus, will not be strong enough to carry the weight of the entire photo, tight shots using telescopes and very long telephoto lenses excepted. Find something exciting to go in the foreground, either an interesting horizon line or a graphic object that juts up into the sky and looks good as a silhouette, such as a truss bridge or lighthouse. Just make sure that the object doesn’t block the view of the comet.

When composing the scene, pay close attention to the other objects in the sky. You may discover that if you expand the view just a tad in one direction, it allows you to include Mercury, Spica, or some other element that will enhance the composition.

Exposure Settings

Since Earth is moving relative to anything in the sky, you want to use a relatively short shutter speed to keep the comet from blurring. You can get by with a little more blur on a comet than you can a star, but you want to be careful and not go too far. And it’s possible that you’ll be including stars or planets in the composition, so shutter speed is definitely going to be a consideration.

The old “rule” of the focal length divided into 500 to determine the longest shutter speed before stars streak is a good start. (Actually, the real rule is 600 divided by focal length, but I use 500 for a little extra insurance.) So, with a 50mm lens you can go 10 seconds before obvious trailing occurs. With a 500mm, you’re looking at only 1 second before trailing occurs. There are a lot of factors that come into play here, but this is a start.

Fortunately, with today’s digital cameras, we can work with this. Open the aperture and crank the ISO up as much as you need. The aperture will be determined by depth of field requirements. It’s best not to include anything too close in the foreground that would require you to stop the lens down very far to achieve depth of field. You probably don’t want to stop down farther than f/4. With the aperture set, check the exposure and choose the ISO based on what will give you the shutter speed you need to keep the comet from blurring.

If the sky is dark and you’re using a wide-angle lens, an exposure of 30 seconds, ISO 1600, and f/4 is a good starting point. Longer lenses will show star trailing in 30 seconds, so you’ll need to adjust. If you’re shooting the comet in a twilight sky or close to sunrise, as we are all sure to be doing, you won’t need this much exposure.

A really cool thing about shooting comets is that they hang around long enough for us to adjust our settings. Take a shot at whatever settings and then adjust as needed after reviewing the histogram and LCD preview.

More To Come

I’ll be keeping a close watch on what’s happening with Comet ISON and will update you as needed. If you sign up for my free Night Photography News eNewsletter, you’ll be assured of getting the updates as soon as possible. Newsletter members will receive the November Night Photography Events Calendar on the 15th of October and the December calendar on the 15th of November. The calendar will have more details about all the other stuff going on in November’s and December’s night sky.

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