If you’ve spent some time looking at the night time sky you’ve undoubtedly seen “shooting stars” on occasions. These are typically tiny pieces of space junk about the size of a grain of sand entering and burning up in the earth’s atmosphere (contrary to their popular moniker, they are not stars). On a few annual occasions, the Earth will pass through a trail of debris left over from a passerby, typically a comet, making the meteor’s more frequent and somewhat predictable. Today, August 14th, we are passing through one of those space debris trails leftover from the passing of comet Swift-Tuttle. The meteors in a meteor shower typically come from a particular point in the sky called a “radiant” and the tails of all incoming meteors will point back to the radiant. The perseid meteor shower is so named because the radiant is in the autumn constellation Perseus. The Perseids are a very long lasting shower that start about two weeks prior to Aug 12th and last about two weeks after, although the greatest activity is around Aug 11-14th (typically).
This past weekend I was up in
Maine
and I managed to photograph a single Perseid meteor (I saw maybe 10 meteors in two nights of watching, very slow shower). So how does one photograph a meteor? Pure dumb luck helps a ton. Here’s how I do it. Before it gets dark, make sure you focus your camera lens at infinity and leave it there. I like to use a lens in the 17-50mm range, the wider the field of view, the easier it is to catch one. A narrower field of view (like with a 50mm lens) will get you a much smaller patch of sky, but if you happen to catch a meteor, it should be a brilliant photograph. Faint meteors will not show up on a wide angle photo, while they will show up with a narrower field of view. So I set my Canon 20d to ISO 1600, 30 second exposures, lens at 18mm f/4 (open the lens f-stop wide open), put it on a tripod and pointed it up. I hooked the camera up to a shutter release cable so after each 30 second exposure, it took another exposure. I took 200 shots in all. Unfortunately, my focus did slip some (still not sure how that happened) so my one meteor is somewhat fuzzy, definitely not good enough for an 8x10 on the wall. Please note, 30 second exposures are enough to show some trailing of stars, but not much, as you can see in the attached photo.
The next major predictable meteor shower will be on Nov 19th as the Leonids put on their annual show.
Gazing at the stars at night already became my hobby. I am always fascinated to look at the stars and read about astronomical facts. Thanks for sharing this post to us. You might also want to meet a guy at zookland doing astrophotography with only $250 worth of equipment. See here, http://www.zookland.com/
Posted by: stargirl@hatboss | November 07, 2008 at 06:07 PM