How To Photograph Comet Pan-STARRS

The first of two comets in 2013 is just around the corner for Northern Hemisphere viewers. Comet Ison won’t light up the sky until November, but now is the time to start the detailed planning for photographing Comet Pan-STARRS. The best time for photography is probably going to be between March 8-20, with the peak occurring from March 11-16.

There is a ton of information on the Internet about the science and viewing of Pan-STARRS. Some of the sites I’ve been visiting include Sky & Telescope, EarthSky, and even the website of my local astronomy club. All of these sites, and many more, provide interesting reading and good information about when and where to see the comet. What I want to do here is talk about what the general night photographer needs to know to photograph the comet.

Here is an introduction to Pan-STARRS from NASA.  

How Bright Is It?

First, for those of you who haven’t been keeping up with the latest comet news, Pan-STARRS is not going be lighting up the night sky like the full moon or a major meteor fireball. At one point it was predicted that the comet could reach magnitude -1 in brightness, which is brighter than most stars, but now it is expected only to reach about +2. (The higher the number, the dimmer the object. Venus at its brightest is around -4, Polaris +2, the full moon -12)

So Pan-STARRS is probably not going to be an earth-shattering naked-eye viewing event. In fact, it probably will be disappointing to the average person. But, and this is a big but, we are going to be PHOTOGRPHING the comet, not just viewing it. The high ISOs, wide apertures, and long exposures we’ll be using will cause the comet to show up in the image far more than it will in a naked-eye view. Also, you can make your viewing experience much more enjoyable by bringing binoculars.

Another reason for why Pan-STARRS will not overwhelm you in brightness is that it will only be viewable while it is very low on the horizon and during evening twilight. By the time the sky has completely darkened, the comet will have sunk below the horizon. Later in March it will still be above the horizon after the end of twilight, but by then it will have move far away from the sun and will likely be too dim to be seen.

While the twilight sky will interfere with the apparent brightness of the comet, it will give us a wonderful photographic opportunity.

Where To See It

Look toward the west after sunset to see the comet. It will be very low on the horizon, so you’ll need an unobstructed view. 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. Beginning in late March or early April, it might be possible to see the comet on the eastern horizon before sunrise, but it probably will have dimmed too much for a good view.

Because the comet will be so 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. Of course, no one in North Carolina will be viewing Pan-STARRS over the ocean since it is in the wrong direction.   

When the comet first appears on March 7 or 8, it will be nearly on the horizon, so you’ll need a totally unobstructed view. It will be at about azimuth 260° (due west is 270° and the sun sets at 265°). The comet rises higher each evening, but is still less than 15° above the horizon on March 20. 


A NASA representation of Comet Pan-STARRS. Don't expect the comet's tail to be this long.

When To See It

Folks in the Southern Hemisphere have already been viewing Pan-STARRS, but it has now moved out of their view and is entering into view for those of us in the Northern Hemisphere. It will probably become visible on the evening of March 7 or 8 for viewers around 35-degree latitude.

You’ll want to start viewing right after sunset. As the sky darkens, the comet will slowly start to appear in the twilight. For the first couple of weeks, it will sink below the horizon before total darkness. Later in March, it will still be above the horizon after astronomical twilight ends, but it will also be much dimmer.

Pan-STARRS makes its closest approach to the sun (perihelion) on March 10, the night before the new moon. From then until about the 16th will be the ideal time to view, when there is the least light pollution from the moon. The best nights of all will be the 12th and 13th. On the 12th, a very thin crescent moon will lie just below the comet in the twilight sky. On the 13th, the thin crescent moon will be higher in the sky above the comet, but still close enough to pair with it for a wonderful photo. If you don’t go out on any other nights, make sure you go on these two.

Lens Choice And Composition

You can photograph Comet Pan-STARRS with everything from a fisheye lens to a telescope. I’ll 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 Pan-STARRS 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 will only be a complementing element and will not be strong enough to carry the weight of the entire photo, extremely tight shots using telescopes 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.

Comet Hale-Bopp

A bad photo of Comet Hale-Bopp. Nikon N90 (maybe), Nikon 17-35mm f/2.8 lens (likely), f/5.6 (guess), 60 seconds (wild guess), Ektachrome 400 slide film (wilder guess).

Exposure Settings

Would now be a good time to tell you that I’ve never photographed a comet before? Well, actually, that’s not totally true. I did take one lousy photo of Comet Hale-Bopp back in 1997. Back then, I had no clue how to take a photo at night, so I guess I should be happy I captured the comet at all. Of course, I was using film, probably IS0 400 or maybe even higher, which gives the image a very grainy look. The long shutter speed causes the stars to streak and not look like the pinpoints of light that I wanted. And I didn’t do a great job with the composition. The campfire is too close to the tent, and I cropped too tightly to the tent on the right side. With Pan-STARRS, I hope to do a better job.

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 a few of the brightest stars or the moon 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.

Just Do It!

For night photographers, some events are just too good to pass up and you should do everything you can to photograph them. Comets, with their rarity and uncertainty, are high up on that list. Yes, Comet Ison promises to be a much better photo opportunity than does Pan-STARRS, but that doesn’t mean you can’t make great photos of Pan-STARRS. If nothing else, you can consider Pan-STARRS as a training exercise for Ison.

Tags: , ,

2 Responses to “How To Photograph Comet Pan-STARRS”

  1. Cindie Says:

    Awesome article!

  2. Kevin Adams Says:

    Thanks Cindie!

Leave a Reply