On Sat, 23 Mar 2002, A.Brown wrote: > Thanks for the usefull information on the more conventional method of > aligning dishes. > I had hoped there was a way of simply aligning a bright spot onto a pre > drawn grid on the dish, however complicated the design and implimentation > was. > I am still not sure if such a device could be "universal" or ones location > would have to be known in advance. > Perhaps a sextant like function could be built in incorporating a bubble > level within the mount. I suspect there would be enough sensitivity on a > 1.2M dish half a degree would be about 5mm on the dish surface. > Curious > Albert
Interesting problem! I was ready to dismiss the "universal" concept, out of hand, but the more I think about it, the more it FEELS as if some of the variables disappear. Certainly, you need to know the date, as the solar declination changes, whereas the satellite's declination does not. You need to know the time, similarly, to correct for EQT. Latitude: Can we discount parallax? Does the N/S displacement induce a serious enough error in satellite declination? Or can we aim the dish at so many degrees south (or north) of the corrected-to-zero Sun, and leave it at that? Longitude: Introduces standard time error, but is this directly related to the azimuth error of the satellite? Significant non-universality would come from the imperfect lines of standard time zones, but that's a simple adjustment of an hour either way, I suppose. Dave 37.29N 121.97W -
