Satellite flare is the phenomenon caused by the reflective surfaces many satellites have today. In their orbits, the antennas or solar panels of satellites directly reflect sunlight. For other uses, please see Satellite (disambiguation) A satellite is an object that orbits another object (known as its primary). ... In physics, an orbit is the path that an object makes, around another object, whilst under the influence of a source of centripetal force, such as gravity. ... A Yagi-Uda antenna An antenna or aerial is an electronic component designed to transmit or receive radio signals (and other electromagnetic waves). ... Solar Panel (photovoltaic array) A Solar panel is a flat collection of solar cells or solar thermal collectors used for converting solar energy into electricity or heat. ...
In the case of the Iridium communication satellites, these flares are predictable and quickly moving illuminated spots of about 10 km diameter when the reflected beam hits the earth. To a spectator this looks like an extremely bright flare in the sky with a duration of only a few seconds (5-20 seconds). Some of the flares are so bright (up to -8 magnitude) that they can be seen at daytime, but they are most impressive after dusk and before dawn. In the case of Iridiums, the flares are caused by the antennas. Iridium satellites normally have a +6 magnitude (the boundary of visible objects in the night sky under the best of conditions). An Iridium phone (without the aerial) The Iridium satellite constellation is a system of 66 active communication satellites and spares around the Earth. ... A kilometre (American spelling: kilometer), symbol: km is a unit of length in the metric system equal to 1000 metres (from the Greek words χίλια (khilia) = thousand and μÎÏ„Ïο (metro) = count/measure). ... A WWI-era parachute flare dropped from aircraft for illumination. ... // Headline text HEY!! HOW ARE YOU ALL?? Its nice of you to come read this page. ... It has been suggested that this article or section be merged with Twilight. ... Dawn or civil dawn is the time at which the Sun is 6 degrees below the horizon in the morning. ...
The Iridium satellite constellation is composed of 88 satellites, some of which are currently inoperable and tumbling. The flares are caused by the MMAs, or main mission antennae. These are highly polished aluminum antennae that can act as a mirror to reflect light from below the horizon back to Earth.
This flashing has been of extreme annoyance to astronomers in that the brightness of the satellites disturbs observations and can damage sensitive equipment. Satellite flare can also be a problem for astrophotographers, as they can appear unwanted on shots of the night sky. Their high predictability, however, makes them an easy target for those who wish to photograph them. An astronomer or astrophysicist is a scientist whose area of research is astronomy or astrophysics. ...
External links
Heavens Above allows you to get predictions for when Iridium flares will be seen from your location
Its financial failure was largely due to insufficient demand for the service, the bulkiness and cost of the handheld devices compared to cellular mobile phones, and the rise of cellular GSM roaming agreements during Iridium's decade-long construction period.
Iridium and other satellite phones may be identifiable to the listener because of the particular "clipping" effect of the data compression and the time lag due to the long travelling path of the signal.
Because of the satellites' peculiar shape with two polished door-sized antennas at 45 degree angles with the main bus, the Iridiumsatellites have a highly visible satelliteflare.
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