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A while back I was observing Uranus with my 6" dob and a moving object tracked across my field of view. I was at about 90x at the time, and the object was pretty bright but slow moving. I dropped down to about 40x and it was still visible, if faint, which allowed better tracking. I followed it for a good 5 minutes until I lost it after a chair bumped my scope. It was clearly moving in the plane of the ecliptic and in the right direction.

If that were to happen to me again, what do I need to have to get a reasonable track on it? Is it just a time plot vs. background stars and my exact location, or is there something more I need?

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How fast was it moving? For example, how long time, approximately, did it take to cross the field of view? 10 seconds, 1 minute, 5 minutes? – Peter Mortensen Jun 1 '11 at 23:58
@PeterMortensen Background stars tracked about third to half way through the FOV when it passed all the way through (non-tracking telescope mount). – sysadmin1138 Jun 2 '11 at 1:56
Not an answer, but I would think that the greatest challenge would be measuring the course precisely enough to project it forward through its orbits. I would think it would be very rare to be able to spot a single satellite twice in an evening, meaning that you'd have to project forward ~24hrs... Sounds like a pretty tough challenge. – Larry OBrien Jul 19 '11 at 17:14

1 Answer 1

up vote 7 down vote accepted

This was almost certainly an Earth satellite. I see them all the time while observing, and have sometimes tracked them across the sky with my Dob. Identifying them would be tricky. Because you saw this with a telescope, it is probably too faint to be in the predictions from Heavens-Above, which only go down to magnitude 4.5:

You'd probably do best with binoculars and a bright satellite, tracking against maps in a star atlas.

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