The annual Perseid meteor shower is coming. The shower begins, gently, in mid-July when Earth enters the outskirts of a cloud of debris from Comet Swift-Tuttle.
No other comet produces fireballs like 109P/Swift-Tuttle–probably a result of its oversized nucleus. The comet’s core is 26 km in diameter, and naturally crumbles into fireball-sized chunks. Since 2008, NASA has counted more fireballs from the Perseids than any other shower.
Dust-sized meteoroids, hitting the atmosphere, will streak across the night sky, at first only a sprinkling, just a few each night, but the rate will build. By August 12th when the shower peaks, sky watchers can expect to see dozens, possibly even hundreds, of meteors per hour.
The easiest way to observe the meteors is to lie down on a sleeping bag or lounger with your feet pointed northeast, looking at approximately 30-45 degrees off the radiant. You’ll soon see meteors racing along the Milky Way.
The Perseids are fragments of Comet Swift/Tuttle and are the fastest meteors of all, often producing very bright fireballs and trains lasting several seconds. Photographing them is relatively easy. All you need is a camera capable of long exposures, with a high ISO speed rating, and a tripod.
Point your camera to about 50º up in the sky and about 40º from the radiant, for best results. Wide-angle lenses are not really suited to meteor photography, granted, they cover more sky, but the images will be very small and you will not pick up the fainter meteors. Initial settings should be an exposure of around 2 minutes with an ISO of 400 – 800. A fast lens with an T-stop of f2.0 or better is preferred. If you are able, set the focus to infinity, or with autofocus lenses, try focusing with a zoomed LiveView on the rear LCD screen and then don’t change the zoom and set the focus to manual. It is important to check your results initially and spending the time to get perfect focus will reap rewards in the results you can expect.
Also, make yourself a little lens hood from a piece of light cardboard to stop your lens dewing up during the evening, or use a dew heater.
Meteor photography is a bit hit and miss so be prepared to spend a few hours or more outside, wrap up warm, use a dew heater on your lens if possible, and bring a spare battery or two. Getting away from light pollution will greatly help your end results.
Article content from niaas.co.uk