[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Re: Iridium Flares

Seems lots of people are having fun watch the Iridium Satellites Flare.
As Cliff Buttschardt points out it is very important to know your location
accurately. As the area the flare is visible within is quite small.

A direct link to prediction software Iridflare is below, this program
requires ansi.sys loaded in config.sys

The elements used should really be as new as possible and not more than a
week old.
A link to elements updated several times a day is

From the visual satellite observers home page

Why They Flare/Glint

 The mechanism providing the flare/glint appears to be the Main Mission
Antenna (MMA)on each of the satellites. These  antennae (of which there are
three- 120 degrees apart, 188 cm  wide x 86 cm long x 4 cm thick each) are
highly reflective  aluminum flat plates (treated with silver-coated teflon
for  thermal control) that are angled 40 degrees away from the axis  of the
body of the satellite. The axis of the satellite body is  maintained
vertical to the Earth's  surface. On each plate are 106  electronic
radiation elements. 

The plate or MMA can provide a direct (specular) reflection of the sun's
disk. This specular reflection is only tens of kilometers wide at the
Earth's surface. In order to see a very bright reflection, the observer
must be within this relatively small area. Prediction programs are
available to determine this area. 

The three sided (similar to an equilateral triangle) satellites themselves
are not very large, aproximately 4 meters long and less than one meter in

Steve Daniels
50.245N 3.34W 210ft