Re: Geosat Solar Transit?

From: Richard Clark (
Date: Mon Mar 06 2006 - 04:33:53 EST

  • Next message: Björn Gimle: "Re: Geosat Solar Transit?"

    On Sun, 5 Mar 2006, satcom wrote:
    > Tried to figure this out a couple of years ago Jeff.....and came to the same
    > conclusion as Tony.
    > The objects would be too small to resolve.
    The Advanced Technology Solar Telescope (currently in the final stages
    of getting aproved) will be able to do this. It is a 1 meter class
    telescope with adaptive optics.
    There are some smaller solar telescopes equiped with AO out there that
    might just detect a transit.
    Of course they do not take whole-disk observations. Fields of view are
    a few arcminutes so it'll take a bit of luck to be observing a feature
    when a sat goes by although with the population density of some parts
    of the clarke belt it will surely happen. Another big if is: will an
    unsuspecting scientist realize what the strange linear feature is. A
    bad row on the ccd no doubt...
    Somehow I don't think this will get very high on the list of science
    > I have manged to see transits of leo craft down to 2 arcseconds with an 8
    > inch scope , but  0.25 arcseconds  , even with a much larger aperture would
    > be near impossible....the target being lost in the "noise".
    > I did wonder at one stage if it might just be feasible using a large
    > telescope and a projection of the Sun's disk onto a large screen.
    > ...
    For several months I was on the lookout for ISS transits at the sites of
    the GONG network. (This is a program with 6 observing sites around the
    world making 'continuous' observations of oscillations of the sun's
    photosphere) Within a week of signing up with Tom's alert service there
    was one at our India site but it was during monsoon when that instrument
    was offline. A couple of others at low elevation after the instruments had
    shut down for the day. Others would show up as alerts 8-10 days in advance
    but as the date of the transit drew near the ground track always seemed to
    recede from the observing site. Never bagged a single one! When you're
    tied to a fixed location, or even 6 fixed locations, ISS transits are
    fairly rare.
    Say, whatever happened to Tom Fly's ISS transit alert anyway?
    Richard Clark
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