Tuesday, June 5, 2012

Catch an Iridium flare and see a satellite!

The other night I went for burgers with friends.  While we sat talking, I noticed my buddy, Patrick, monkeying with his phone.  He consulted an application, and told us the Chinese space station would pass over in 4 minutes, and an Iridium satellite would flare in 11 minutes.

All of us jumped up at the same time.  We stood outside the restaurant and consulted phones, maps, apps and the North Star to get us pointed in the right direction.  Upon seeing a half dozen guys staring up at the night sky, various random people came over to see what we were doing.  Our explanations produced blank looks and the random people wandered off.

Honestly, although I knew about the Chinese station, I'd never seen it.  And while I'd seen flares from the International Space Station (ISS), I'd never watched an Iridium satellite flare.  There were scattered clouds that night, so we didn't see the Chinese station, but the Iridium satellite treated us to brief, but bright show.

What is a satellite or space station flare? When an object in orbit above the Earth turns at just the right angle to the sun, it reflects the sun's rays and is visible from the ground. 

With the ISS, you have an object as long as a football field floating in space.  But with the Iridium satellites, the antenna providing the reflection is only about the size of a door.  It's pretty amazing to think you can see the flash of a door-sized object that's 485 miles (or 780 kilometers) up in space.

If you'd like to see a space station or a satellite flare, go to Heavens Above and enter your location.  This site provides the time the satellite will pass over your location, plus the magnitude (or brightness), the altitude and the azimuth (or direction.)  Strangely, when it comes to magnitude, negative numbers are better, so look for flare events that are listed as -2 to -7.

There are applications for smart phones that will help you find a flare in your area.  With over 80 Iridium satellites still in orbit, flares happen frequently, so as long as it isn't cloudy where you live, you can probably see one this week.

(Here is a site called "Catch a Flaring/Glinting Iridium" which explains Iridium satellites and their flares in detail.  Astrosat also has an explanation and data for observation from major world cities.  The cool picture is from: epod.usra.edu by photographer Sean M. Sabatini.  The cool idea for this post is from Patrick.)

(If you enjoyed this article, please leave a Comment, or hit one of the buttons in the box below and share it on Facebook or Twitter.  Thanks!)


  1. I think it's awesome that you have a group of friends that will jump up and run outside to see an Iridium satellite flare! That's pretty cool! I shared on my Facebook :)

  2. Thanks for sharing on Facebook. I think this is something people will enjoy, and actually seeing a satellite is a good reminder of what science and hard work can accomplish.

  3. Fun blog, Mark, and I agree with Akopp. Any friends that will run outside to stargaze with you are special indeed.

  4. Indeed, you're right, Tony. It's good to hang out with folks that have similar interests.

    Thanks for commenting!