Re: Geostationary Eclipse Season and Geosat Flares are here!

From: Brad Young via Seesat-l <>
Date: Thu, 22 Feb 2018 21:57:56 +0000 (UTC)
I don’t know if anyone else has responded Bob but it’s pretty easy. Instead of a table (which is probably in the archives) here is a method which is in the teach a guy to fish mode. 
Whenever the sun reaches the declination where are your Geosats lie, that is the best date to see them. For instance, for me at 36° North, Geosats appear at -5.3 declination. The date the sun appears at that declination is around March 7; from JPL Horizons Sol ephemeris:2018-Mar-07    23:09    -05 28
To figure out what declination your Geosats appear at, use any Look Angle for Communications Satellites calculator. It will give the altitude of the satellite. This altitude, minus your coincident latitude angle, is the declination of the geo belt from your location, e.g.
Look Angle output = alt = 48.7 deg at 36 deg latitudeCoincident Latitude Angle = 90-36 = 54 degGeobelt appears at = 48.7-54 = -5.3
Whatever you do, please inform folks not to look at the midnight point (antisolar), as this is the depth of shadow! They should look an hour before or after the antisolar point. So e.g. for me, the antisolar point is 11h 09m RA on March 7 (notice the sun is at 23h 09m RA in the JPL output above). I should look in eastern Hydra and western Virgo. There are key asterisms that are favorites to look for these birds also, in these constellations. If you like, I can send those along too, but the list rules make some of this data hard to send.
Brad Young

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Received on Thu Feb 22 2018 - 15:59:15 UTC

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