Re: ISS transit across sun

From: Thomas Fly (
Date: Wed Feb 26 2003 - 18:31:51 EST

  • Next message: Rainer Kracht: "Milstar 5"

    > My watch alarm went off and I started to count
    > up. 1, 2, 3, 4, 5, 6, 7, 8, ..............10, 11 and on up to 30. The
    > station was supposed to cross at 8 seconds past the minute! We saw
    > :~(  I suppose the sun's intensity overwhelmed the tiny silhouette and the
    > clouds ruined enough of the clarity that we didn't have a chance. It was
    > only going to be visible for about a second.
    Depending upon the angle above the horizon (i.e., the distance to the space
    station) it can take as little as .4 seconds to cross the face of the sun or
    moon.  Also, being as little as 1 mile off the transit track can be the
    difference between seeing a dead-center transit, or nothing at all.
    The space station's silhouette wouldn't necessarily be so small- if the ISS
    is ever completed, it should be about the same angular size as Jupiter, when
    passing directly overhead (i.e., about 2% the angular size of the sun &
    Finally, it's possible that the program's prediction was wrong, as extreme
    accuracy is obviously required.  Accurately predicting a transit for the
    setting/rising sun/moon might be especially difficult, since at that low
    angle, the observation location may even have a significant dependency upon
    the local air temperature, which affects the amount of atmospheric
    > Has anybody successfully seen the ISS cross the sun's disk? Has anybody
    > taken a video of it? It was 2:05 PM my time.
    I've seen the ISS pass across the face of the moon, and have a pretty
    piss-poor picture to prove it:
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