One of the best meteor showers of the year is less than two weeks away! The annual Perseid meteor shower is expected to produce an average of around one meteor every minute for viewers in the United States, although the actual rate could be more.
The peak for this year’s shower occurs mid-afternoon on Monday, August 12 for the Eastern Daylight Time zone. Obviously, you won’t be able to view any meteors at this time because it will be in the daylight, but that’s not necessarily a bad thing. Meteors don’t adhere to any strict schedule, so it’s always a good idea to go out both before and after the expected peak period. In fact, the Perseids are active from around July 17 to August 24, although the numbers are far less when you get a day or more away from the peak.
The good thing about the peak being in the afternoon this year is that there is a good chance of seeing good numbers of meteors both on the night before and the night after the peak. So for this year’s shower, the ideal viewing time will be the morning of August 12 and the morning of August 13.
Oh, if you should happen to see a meteor during the peak on Monday afternoon, you had better run for cover because that’s going to be an Earth-shattering event. Literally!
Typically, the best viewing for any meteor shower occurs from about midnight to dawn and the Perseids are no exception. Serious viewers and photographers will want to start around 11pm on Sunday, August 11 and stay out until dawn on Monday morning. Then go back out on Monday evening at 11pm and stay out until dawn on Tuesday, August 13.
Meteor showers are named for the constellation or brightest star that lies nearest the radiant, and in the case of the Perseids, that’s the constellation Perseus, which rises in the northeastern sky. If you trace a line backward from any Perseid meteor, the path will lead to Perseus. However, you don’t have to look toward the radiant to see meteors, as they can occur anywhere in the sky. In fact, you’ll probably see more meteors by looking away from the radiant. When you look directly toward the radiant, some of the meteors will come at you head on and won’t produce long streaks of light.
However, the radiant does need to be fairly high above the horizon for you to see the most meteors. If it is too low, many of the meteors that emerge from it will be hidden below the horizon. That’s why the best meteor watching generally occurs after midnight, when the radiant has risen high in the sky.
The moon can create serious problems for both viewing and photographing meteors. When the moon is at full phase, only the very brightest meteors will show. Even a crescent moon will cause enough light pollution to drown out some of the meteors. Fortunately, the moon will not be a factor for the 2013 Perseids. The waxing crescent moon sets at 10:51pm (EDT) on the 11th and at 11:29pm on the 12th. Perfect!
It’s possible that some of the meteors you see won’t be Perseids. Sporadic meteors can occur on any night, and during the Perseid meteor shower there will also be two other minor showers occurring, the Kappa Cygnids and Delta Aquarids. To determine whether the meteor you see is a Perseid, simply trace its path backward. If it leads to Perseus, you got yourself a Perseid.
One really cool aspect of the Perseids is that they can produce very bright bursts of light that often leave trains lasting for several seconds. And they can be colorful. Some of the Perseids I’ve photographed have a definite green hue. Perseids are fast, though, which makes them a little harder to view and show up in photographs. The slower the flash of light, the more time it has to register with your eyes and to record on a camera sensor.
Photographing the Perseids
Basic meteor photography is pretty simple. Point the lens at a section of sky where you think (hope) a meteor will occur, lock down the shutter to shoot continuous exposures, and then cross your fingers for a flash of light. How well you execute the process will determine success as much as whether or not you see any meteors.
First, find a dark location, as far away from city lights or other light pollution as you can get. You may see some very bright meteors in a light-polluted sky, and if that is your only choice, go for it. But to see the most meteors, dark skies rule. This goes for light pollution from the moon, as well, but fortunately, the moon won’t be a factor in the 2013 Perseid meteor shower.
You might think that the best direction to point the lens would be toward Perseus, the shower’s radiant, but that is not the case. Meteors can appear anywhere in the sky when the radiant is above the horizon. With most showers, you’re just as likely to spot a meteor away from the radiant as toward it. In fact, you may see fewer meteors if you look toward the radiant. Looking in that direction, some of the meteors you see will be coming at you head on and will not produce long streaks of light. But if you look at a right angle to the radiant, the meteor streaks will cover a longer portion of the sky. The best approach is to choose the direction based on light pollution and compositional elements.
There are two basic approaches for photographing meteor showers. You can shoot a star-trail sequence that has meteors streaking across the star streaks or you can shoot a static star scene.
For star trails, you’d set it up just as you would any star-trail scene and hope that some meteors occur during the sequence. With the camera mounted on a sturdy tripod, shoot continuous exposures and stack the frames in the computer to create the final image. Change the blend mode to Lighten so that all of the trails show up. A few software apps will do the stacking for you. StarStaX appears to be a good multi-platform app and it is free. I haven’t tried it yet, so can’t make a recommendation.
My base exposure for star trails is f/2.8 or 4, ISO 400, and 4 minutes. Do a test to make sure the exposure is not blown out by light pollution, and then adjust as needed. You can record more stars and fainter meteors if you shoot at higher ISOs, but you may have to shorten the shutter speed to keep from overexposing the sky. Also, at higher ISOs, you get more noise and the signal-to-noise ratio comes into play. For instance, at ISO 1600 and 30 seconds you might be gathering a lot more noise compared to the signal (the light you want to record) than you would at lower ISOs and longer shutter speeds. However, with a newer camera, the noise probably won’t be that bad at ISO 1600 if you keep the shutter speed to 30 seconds or less.
A good compromise exposure for star trails and meteors is something in the 60-second range at ISO 800. Just keep in mind that the shorter the shutter speed, the more exposures you have to make to get the long trails that look so cool. If you have a slow computer or you are stacking the frames manually in Photoshop, you could be in for slow, tedious process.
While meteors streaking through star trails look good, I typically prefer to photograph them as part of a scene where the stars appear as pinpoints of light instead of streaks. The meteor streaks contrast with the pinpoint stars, acting as strong components of the composition.
For the most effective compositions, you want to compose a scene that works well without meteors. Ideally, you want some sort of foreground element in the scene, instead of just a bunch of stars. But remember, you want to include as much sky as possible to increases your chances of capturing a meteor, so choose the foreground carefully. An ideal foreground is one that looks good in only the bottom one-sixth or so of the frame and has an interesting top line, like a jagged mountain range.
If the foreground doesn’t work as a silhouette against the sky and if it is close enough, you can light paint it to make it stand out. Shine a flashlight or pop a flash on it. You can get creative with choosing foregrounds to light paint. Campsite scenes with lighted tents are always a good choice, but anything that you can throw a little light on is a candidate.
If the foreground projects far up into the sky, it should be one that has graphic lines that work well as silhouettes and something that doesn’t have a lot of mass so some of the stars will show through. Bridges, towers, isolated trees, lighthouses, and similar subjects all work well.
Whatever you choose as the foreground, make sure it is far enough away that you can shoot wide open and still have enough depth of field so that it, and the stars, are in focus. For a wide-angle lens, that point may be closer than you think. With a 17mm lens, you have DOF from about 10 feet to infinity at f/2.8. With the 14mm lens I often use, DOF is from 6 feet to infinity at f/2.8. But I don’t like to cut it that close. To achieve the full DOF, you have to focus precisely at the hyperfocal distance, which isn’t the easiest thing to do at night. I typically like to have the foreground at least 25 feet away, and even farther is better. That way, I can focus precisely on the foreground, knowing it and the stars will be sharp. Of course, I always check for sharpness in both the foreground and the stars before letting the camera run.
In addition to choosing a good foreground, you should pay attention to what’s in the sky. Try to use prominent constellations or star patterns as complementing elements. For the Perseids, the Milky Way is always a strong compositional element.
Once you set up the composition, the exposure for a pinpoint star scene will be the same as on any other night. Assuming a relatively dark site, the main consideration will be shutter speed, because at a certain speed the stars will begin to streak. For this reason, as well as for making the best compositions that increase your chances of capturing a meteor, a wide-angle lens works best. I should point out that the wider the lens, the fainter the meteors record. So while a very wide-angle lens increases your chances of capturing a meteor within its field of view, if the meteor is very faint, it will not show up well in the photo. Still, I prefer to cover as much sky as possible with the composition.
To determine the point at which stars appear to show obvious streaks, divide the focal length of the lens into 500. So for a 17mm lens, you can get by with about 30 seconds. This is just a general guide and it depends on the direction in the sky that you shoot. (The stars will appear to streak more when shooting toward the south, and if you magnify the image, you can see streaks after only a few seconds with any lens.) Since it isn’t precise, and since 30 seconds is the longest shutter speed that my camera allows without using the Bulb setting, I typically shoot night sky scenes at this speed with focal lengths from 14mm to 18mm.
Set the aperture wide open or close to it. For most lenses, this will be f/2.8 or f/4. The only reason not to use f/2.8 (or wider if you’re lens offers it) is if your lens suffers from coma, a lens aberration that causes stars to record as little snow angels instead of pinpoints of light. Coma is reduced as you stop the lens down. Even the difference between f/2.8 and f/4 can be significant, and by f/8, it is usually not noticeable. My Nikon 17-35mm lens has horrible coma, so I never shoot it at f/2.8. Actually, I rarely use the lens for night photography anyway, much preferring the Nikon 14-24mm.
Try ISO 1600 as a starting point. Do a test exposure and see how it looks. If there is a lot of light pollution in the sky, you might have to back off a little. At a dark site, you can definitely shoot 30 seconds at f/2.8 and ISO 1600 without any problems. If your camera doesn’t have a lot of noise, you can shoot at even higher ISOs.
Once you get the composition and exposure set up, set the shutter to shoot continuous exposures and just let it rip. With a locking cable release, you can set the shutter dial to shoot continuous exposures and then walk away and let the camera do all the work. Most Nikon (and Canon, too, I think) cameras only allow you to shoot 100 exposures this way. To shoot more than 100 shots at a time, you have to use an intervalometer, either an external one like the Nikon MC-36 or the Canon TC-80N3, or, if you’re a Nikon shooter, the internal one that’s accessed in the menu. Note that the built-in timer will only allow you to shoot exposures up to 30 seconds long. If you want to go longer, such as when shooting star trails, you have to use an external intervalometer.
Of course, it’s a simple matter to shoot 100 exposures and then start the sequence again. In fact, you probably don’t want to shoot more than that at a time anyway, because during those 50 minutes the stars will have moved a considerable distance in the field of view. If you compose the scene to take advantage of constellations or the Milky Way, you’ll have to recompose periodically throughout the night.
So the idea with both star trails and pinpoint stars is that you get everything set up and then let the camera do the work for a while. You want that camera making exposures for as much of the night as possible, so try to work quickly when you recompose or change batteries or something. There’s nothing worse than witnessing the most spectacular meteor of the night while you’re switching out memory cards!
Regardless of the method you choose for shooting meteors, your camera is going be exposed to the night air for a long time and you need to be aware of the possibility of dew forming on the lens. Read this article for detailed info on preventing dew. I’ll have two cameras set up for this year’s shower and both of the lenses will be wrapped in LensMuffs.
Okay, grab your gear and go catch a falling star!meteor showers, meteors, Perseid meteor shower, photographing meteors