Re: Viewing dark objects against a bright background

From: Jonathan T Wojack (
Date: Thu Jan 25 2001 - 07:39:43 PST

  • Next message: Kevin Fetter: "Re: Viewing dark objects against a bright background"

    > The effect called irradiation limits the angular size 
    > one can distinguish the silouete of an object against a bright 
    > background.
    > In the case of the Sun this lower limit on the size is about 1 
    > arcsecond.
    > For Geostationary satellite ranges ( 40,000Km) this means about 200 
    > meters
    > or yards. So maybe just Milstar but not the ASTRA cluster.
    > For the lower NEO's at ranges of 1000KM the lower size limit is 
    > 5meters.
    > So I think detail would show on the lacrosses , the Keyholes
    > and maybe HST. I also think that short exposures would be required
    > ( or tracking) to reduce image motion blur to acceptable limits.
    So, if ISS was passing across the disk of the Sun, I should definitely
    see it?
    BTW, is there any program out there that can compute passes for objects
    that cross the disk of the Sun?
    Jonathan T. Wojack       
    39.706d N   75.683d W  
    5 hours behind UT (-5)
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    This archive was generated by hypermail 2b29 : Thu Jan 25 2001 - 07:57:45 PST