Neal, One problem to tackle is that the satellites and stars don't have the same angular velocity. I.e., you can't directly compare a star trail to a satellite trail. Correcting for that is rather complex. Also, very bright objects (like the ISS) tend to get saturated. As far as simply measuring pixel values in a photograph, software like MaximDL can do that (that is what I use for the flare graphs). - Marco npr61 schreef: > Hello: > > Are there available software that could be used for comparative > photometry of a bright sat, i.e. ISS, trail? Have been toying with the > idea of buying a used Digital Rebel, fitting it with a 50mm f/1.8 lens, > and then taking short, say 8-12 second unguided exposures of the ISS > against brighter background stars. Ideally, it would be nice to be able > to create a rectangular aperture over all or a portion of the ISS trail, > with circular apertures for the ref/check stars. > > I've no background in this subject other than a lot of reading over the > last few months. The goal would be a simple and fun way to put > brightness numbers on a given pass, to perhaps the accuracy of that of a > good visual observer. Am very much considering AIP4WIN for general > knowledge, but don't think that it could perform the task. On the other > hand, wrestling with something like IRAF would perhaps defeat the "fun" > intent. > > Any advice would be welcome. > > Thanks, > > Neal Robichaux > 29.9884N > 92.1498W > > ------------------------------------------------------------------------- > 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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