Jeff Hunt asked ... > This is not directed specifically to Ed alone, but how do you determine > the magnitude value of a sat to the the tenth value? Do you use a > reference star, a light measuring device (photometer)? ... What we do is use reference stars. My wife and I have been trying to see as many objects as we can see with our unaided eyes and during a particular pass, we note what nearby star(s) the object looks like and record the results to the tenth of a magnitude (even though we can't support any claim to such a level of absolute accuracy). For example, we might note that an object "sorta" looked like gamma Cygni or epsilon Cygni. Using assumed magnitudes of 2.20 and 2.46, respectively, for those stars, I'd record the observed magnitude of the satellite as 2.3 . Of course, as we've discovered, many satellites vary CONSIDERABLY in brightness (even after correcting for slant range and phase), by magnitudes - not just tenths :) and so far, we haven't graduated to the level of systematically measuring such variations :( (too little time, etc.etc.). Clear and dark skies! Ed Light Lakewood, NJ, USA N 40.1072, W 074.2317, Hgt +21m