Re: Time to for the geo sat's to start going into shadow

From: Bjoern Gimle@GlocalNet (Gimle@GlocalNet)
Date: Thu Feb 26 2009 - 15:23:37 UTC

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    The geoflare season is obviously not centered around the maximum shadow 
    period - since it does depend on the observers latitude.
    At these time (equinoxes) shadow entry/exit are about 9 degrees off the 
    proper RA (evening entry/morning exit is closer due to parallax of diurnal 
    When the Sun is at the same declination as the geos are, the entry/exit 
    points are closer (unless you observe from the equator).
    In my case, at 59.25 N, the geos are at -8, so they are nearly free from 
    shadow when they pass closest to the flare center.
    All this is assuming the operational geosats' panels point at the Sun's RA, 
    but in the equatorial plane, which explains most geoflare observations.
    If they have a pointing error, is it larger in RA or in declination? If 
    small in RA, the best time is now for northern observers, three weeks after 
    equinox in the S.
    You can use to find the outline of the 
    shadow, and the ideal flare position, at any time.
    ----- Original Message ----- 
    > It's time for the geo sat's to start passing into the earth's shadow.
    > Now go away clouds, so I can observe them flare up, before they go into 
    > shadow, and make for a nice show :)
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