Tried to figure this out a couple of years ago Jeff.....and came to the same conclusion as Tony. The objects would be too small to resolve. I have manged to see transits of leo craft down to 2 arcseconds with an 8 inch scope , but 0.25 arcseconds , even with a much larger aperture would be near impossible....the target being lost in the "noise". I did wonder at one stage if it might just be feasible using a large telescope and a projection of the Sun's disk onto a large screen. However , just for fun , and as here in Europe we have the seven bird Astra fleet to look at , back in 2003 I did a composite of what such an image might look like....mainly to see how much of the disk the co-located birds would cover. The result can be seen here..... http://www.satcom.freeserve.co.uk/astrasunout.jpg Regards, John ----- Original Message ----- From: "Tony Beresford" <dberesford@adam.com.au> To: "Jeff Umbarger" <jumbarger2000@yahoo.com>; <seesat-l@satobs.org> Sent: Sunday, March 05, 2006 6:08 AM Subject: Re: Geosat Solar Transit? > At 14:21 5/03/06, Jeff Umbarger wrote: >>Hey All, >> With the declination of the sun between -10 and 0 >>degrees declination for the next few weeks, would this >>not mean that if we were monitoring the disk of the >>sun, we would see geosats transiting the sun for the >>northern hemisphere? At my latitude (+33.0 deg) the >>geosats appear at around -5.25 deg declination and >>that is where the sun will be next Tuesday. Has anyone >>ever seen this before? That is, is worth watching for? > Jeff, > The problem is the extremely angular size of even the > largest geosat solar panel span. > A back of the envelope calculation says a 30meter span > at 36 megameters is about a 1/4 arcsecond. > so we are talking about a 20 inch telescope > to resolve it theoretically. However the killer is the > irradiance from the photosphere which will fill in > any dark patch of airy disk size , let alone something > much smaller. > > Tony Beresford > > ------------------------------------------------------------------------- > Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: > http://www.satobs.org/seesat/seesatindex.html > > > ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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