EORSAT brightness- was: Iridium Obs, 7 May 97. + ot / Re: What is it? / Re: Azimuth 0, once again
Bjoern Gimle@tt-tech.se (Gimle@tt-tech.se")
Fri, 09 May 1997 10:25:53 +0200
Subject: EORSAT brightness
Was: Iridium Obs, 7 May 97. + ot / Re: What is it? / Re: Azimuth 0, once
again
In message
http://www2.plasma.mpe-garching.mpg.de/sat/seesat/hyper/0440.html
970507 Rob Matson wrote:
....
>#12054 (Cosmos 1220), at a surprising magnitude 2 passing very
>close to Arcturus
I am not surprised, since #12054 is an old (the first?) EORSAT
(orbit raised, when it should have been brought to decay?)
I have always found all EORSATs to be bright and steady. I have
seen no flashes, and the magnitude seems to change regularly
with phase and range, otherwise irrespective of azimuth or
elevation (*), or whether it is operational or not.
I am more surprised by the implications of the answer, to a
previous message from me on this subject,
( http://www2.plasma.mpe-garching.mpg.de/sat/seesat/hyper/0393.html )
by Phillip Clark, who of course has a very solid knowledge
of these things :
------http://www2.plasma.mpe-garching.mpg.de/sat/seesat/hyper/0394.html------
On Sat, 3 May 1997, Bjoern Gimle wrote:
> This is the oldest still active EORSAT
> Ted Molczan lists them as 6.0 m "spheres".
We now know that these satellites actually look like. The body is a
stepped cylinder which starts off with a ring some 3m diameter - posibly
to mate with the Tsyklon-M second stage. The main body is around 2m
diameter and the overall length is around 7-7.5m. The Russians have not
given actual dimensions. The satellites carry a pair of large solar
panels.
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The solar panels can explain the brightness, but why are EORSAT's
magnitude variations so predictable ?
(*) On a complete sidetrack, which is (are?) the correct term pairs :
azimuth/altitude , azimuth/elevation, or azimuth/height ?
I.e. which term should we use for what we measure in km, miles,
or nautical miles over Earth's surface ?
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