Iridium Flare over Organ Pipe

Iridium is a constellation of more than 70 communications satellites that are continuously circling the Earth. Iridium flares occur when sunlight reflects off an antenna of one of the satellites; they last only a few seconds and look like a slow-moving meteor. These flares can be as bright as magnitude -8, and can easily be seen even from the city! I photographed this bright flare under the dark skies of southwestern Arizona; an organ pipe cactus and two saguaro cactuses are silhouetted in the foreground.

Iridium flares are much easier to view and photograph than meteors, because they can be accurately predicted! The Heavens Above web site can tell you what flares will be visible from your location. You can pick from a list of major cities, but since Iridium flares are very location-sensitive, enter your exact location in latitude and longitude (preferably within 0.01 degree of latitude and longitude, or about 1 kilometer). The site will tell you exactly when and where to look for each flare, as well as how bright it will appear. One hint: the orbits do change over time, so be sure to download a fresh prediction within a day or two of when you plan to observe. Good luck and good viewing!

Location: Organ Pipe Cactus National Monument, Arizona
Date: March 15, 2007
Time: 8:43 p.m. MST
Camera: Olympus OM-1 35mm SLR on fixed tripod
Film: Kodak Elite Chrome 400 slide (pushed one stop)
Focal length: 40 mm
Aperture: f/2
Exposure time: 120 seconds
Scanner: Nikon Coolscan LS-2000