Friday evening using a 12.5" dob I followed the ISS for several second (about 15) after it went dark as it passed into Earth's shadow . It was still faintly visible when I lost it in the trees. It would take almost a minute for the ISS to move far enough down range before the Sun would be 6° below the horizon as seen from ISS and still within the region of Civil twilight -- as seen on Earth (as tested using Guide 8). I think that would still be enough light to illuminate ISS so it could still be seen in a telescope at about 100x. Being above the Earth's atmosphere will change the amount of twilight but by how much?? I'm sure the extent of twilight could be checked on video taken from the ISS. Larry Wood On 01/05/2011 6:36 PM, Bob King wrote: > Hi everyone, > I've always wanted to ask this question. No doubt some of you have > followed the space station into Earth's shadow, where it's visible for > some time with binoculars. Is it being illuminated by the moon or ??? > Thank you for your help! > Best wishes, > Bob > _______________________________________________ _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-l
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