Re: GEO Orbit Determination

From: Nick James via Seesat-l <>
Date: Sun, 22 Aug 2021 13:21:06 +0100
Hi Andreas,

As Marco and Rainer have said Astrometrica is probably not ideal for 
this. I use it a lot for comet and NEO astrometry and it can measure 
trails if they are relatively short. You can also take lots of short 
images and stack them at different offset rates which is very useful for 
NEOs and could be useful for GEOs if you get the exposure short enough. 
It can also work with reasonably wide fields if you set it to use a 
reasonably high polynomial fit for the astrometry. I've used it to fit 
fields up to 15 degrees wide but it can be a struggle.

This image is a 2.5 x 1.5 deg field centred on M42.

When M42 is near the meridian it is close to the Geo arc at my latitude 
(52N). There is an out-of-plane Geo streak on this 60s exposure image 
and you can measure the RA/Dec of the start and end manually using a 
crosshair but it wouldn't be much use for an automated system.

That's for slow moving GEOs. I doubt if it would be much use for a LEO. 
I would have thought that you were better solving a stack of frames for 
RA/Dec and then measuring x,y coordinates of the moving object in each 


On 21/08/2021 23:49, Andreas Hornig via Seesat-l wrote:
> Hi there,
> I know this is an older thread, but I am also interested to know how the
> astrometrica software behaves and how easy it is for satellite detection?
> My approach is to determine the ra/dec with software. That
> works reasonably well with the video I have from the Transporter 2 Mission
> of this June. The satellites I detect myself. But it takes a while for both
> (my code and the astrometry part).
> Maybe astrometrica is better there. But before I start the 100 days trial,
> I would like to know here if this can be applied also to leo satellites.
> Best regards,

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Received on Sun Aug 22 2021 - 07:22:27 UTC

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