Regarding Geos

From: Brad Young (
Date: Sun Aug 26 2012 - 16:31:33 UTC

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    Had a few questions about these objects off list, so I thought I set this out there for comment and hope it answers a few questions.
    There's a lot of confusion to be had with terminology. Geostationary objects are active stabilized objects that stay right over a spot on the equator and have an orbital period that matches the earth's rotation. Geosynchronous objects match the period, but are inclined a bit to the equator, and so trace a figure eight in the sky. There are also retired or misfired objects that have orbits that are nearly the same as earth rotation, but they drift (generally to the west) slowly as they are a little further out than the truly synchronous orbit.
    These objects will appear within +/- 20 degrees of the local celestial equator (think Orion's Belt in winter, Aquila in summer. They appear north of the equator in the southern hemisphere, and south of it in the north. E.g. I am at +36 declination, so the stationary objects appear at -5.6 declination in the sky.
    Elsewhere in the sky, objects will generally show motion, except in the highest (apparently slowest) point of the Molniya orbits. However, these are generally very faint and I don't remember seeing anyone flared by one of these objects.
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