>thinking of obtaining a broken trace. "bent" is a better word here than "broken". >Either my reasoning is wrong or the effect is so small as to be >undetectable. Yes, undetectable. A typical field of view is 1 degree. It would take 4 minutes for stars to cross from one side to the other. A typical LEO would take 1 second. Your field of view may be larger but the point is the ratio of velocities is about 300 to 1. Even if the LEO is perpendicular the arctangent of 1/300 is .2 degrees. Probably too small to measure. You need a satellite much higher that takes more like 1 minute to cross the field of view. Of course these are very faint. - George Roberts http://gr5.org -----Original Message----- From: Giuseppe N. Gerbore Sent: Sunday, March 13, 2011 11:10 AM To: seesat-l@satobs.org Subject: Sidereal Tracking vs Fixed Scope Bad weather, no obs possible, let's revert to theory. We are capturing a LEO satellite on a CCD. There are two setups: 1) Mount tracking stars in sidereal mode 2) Mount still The trace on CCD should have a different slope, because in case 1 what we obtain is the resultant of Earth velocity vector and Sat velocity vector. Not being able to capture with two simultaneous setups on the same satellite I stop tracking in the middle of the FOV, See this image to understand what I mean. http://img864.imageshack.us/i/siderealtrackingvsfixedr.jpg/ As far as now I could not prove the above. Either my reasoning is wrong or the effect is so small as to be undetectable. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://mailman.satobs.org/mailman/private/seesat-l/attachments/20110313/9665f0d2/attachment.html _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-l _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-l
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