Iridium Flare

Copyright 2013 Deborah M Zajac. All Rights Reserved

Iridium Flare?I took this photo last month when I was shooting in Fremont Peak State Park with several Night Sky Photographers. This is one of the set-up/ test shots I took before starting my star trail sequence. After uploading the frames I was going through them and discovered I may have caught an Iridium Flare. Iridium Flare is the sun reflecting off communication satellites orbiting in space. ” The Iridium communication satellites have a peculiar shape with three polished door-sized antennas, 120° apart and at 40° angles with the main bus. The forward antenna faces the direction the satellite is traveling. Occasionally, an antenna reflects sunlight directly down at Earth, creating a predictable and quickly moving illuminated spot on the surface below of about 10 km diameter. To an observer this looks like a bright flash, or flare in the sky, with a duration of a few seconds.

Ranging up to -8 magnitude (rarely to a brilliant -9.5), some of the flares are so bright that they can be seen in the daytime; but they are most impressive at night. This flashing has caused some annoyance to astronomers, as the flares occasionally disturb observations and can damage sensitive equipment.

When not flaring, the satellites are often visible crossing the night sky at a typical magnitude of 6, similar to a dim star.” ~Wikipedia

I realize the flare is hard to see in this photo so I’ve zoomed in on it and cropped it out to enable one to see it better. It has the classic shape of Iridium Flare. I took this photo on May 11, 2013 at 9:06pm PDT.

Close of FlareI need to check out the site that has predictions to see if this could be Iridium Flare.  I think the site is called Heaven’s Above.

Nikon D700| Nikkor 16mm Fisheye lens

Update: After checking the Heaven’s Above site to see if there was an Iridium Flare predicted on the date and time I took this photo I found there was a predicted flare on May 10, 2013 at 19:31 h.  in the same place in the sky as this flare. I’m confused. Nothing was listed for May 11th. The site says all times are local. Do I need to factor in Daylight Savings time? I wondered if it could another satellite?  Searching the sites FAQ’s I found this.

Q. While I was out waiting for a flare or other satellite to appear, I saw another flare which wasn’t in the predictions. What could it have been?
A. This was probably a flare from a failed Iridium satellite. Several satellites have failed in orbit, and are not in the nominal orbit and/or attitude. However, they can still produce flares just like the operational ones. The difference is, that we can’t predict when they will happen.

A penny for your thoughts...

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