What is an Iridium Flare? Iridium is the name for a series of around 60-70 numbered communication satellites orbiting the Earth. The ‘flare’ is simply the reflection of sunlight off the satellite’s solar panels. You see this reflection as a sudden burst of light, a flare, as the satellite re-positions its orientation to the Earth to keep its antenna aimed at ground-based antennas.
Given the time, direction, and altitude for Iridium Satellite #3 and the Starry Night Pro program I was able to see what the satellite’s path would look like. For this particular satellite it would travel toward the southwest below the length of the summer triangle asterism from near the star Deneb toward the small constellation of Delphinus the Dolphin, as the labeled picture at the top of the page shows. Then it was simply a matter of setting up my trusty Canon Rebel T3i on a tripod and doing a series of test pictures trying to find the best settings.
For the satellite flyby – which was totally unexpected – I was using 3.5 second time exposures at F4.0, with an ISO setting of 1600. These are also the settings I used for the flare sequence of pictures. Some of the pictures have additionally been enhanced using Photoshop and Image Enhancement/Auto Levels settings.
Click here to read about and see additional pictures of the ISS and Iridium flares.
To pause the slideshow move the cursor over the pictures to bring up the controls.
Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.