Satellite flare

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A simulated animation of a typical iridium flare
Iridium Flare and comet 17P/Holmes
A 30-second exposure of a flare produced by an Iridium satellite


An Iridium satellite

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 travelling. 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.[citation needed]


Viewing satellite flares[edit]

While satellites may be seen by chance, there are websites and smartphone apps which provide location specific information as to when and where in the sky a satellite flare may be seen.[1][2][3]

See also[edit]