Solar transit: satellite?

From: Ed Cannon (ecannon@mail.utexas.edu)
Date: Mon Mar 17 2003 - 01:52:48 EST

  • Next message: Bjorn Gimle: "Re: Solar transit: satellite?"

    I received the following account of a solar transit.
    Might it have been a satellite?
    
    Ed Cannon - ecannon@mail.utexas.edu - Austin, Texas, USA
    
    > observation I made last October 5.  I was observing 
    > the Sun with a 4" inch refractor and sun filter at 
    > about 100x.  I observed a disk-like object cross the 
    > sun.  It crossed in about 4 seconds, and was approx 
    > 30" in size, seemed to move geometrically straight and 
    > uniformly, moving approx sw to ne.  It passed near a 
    > sunspot, whose size I measured, so I think my size 
    > estimate is very good.  The timing was rougher, since 
    > I was totally surprised.  The date was 5 Oct 2002 
    > approx 3pm Austin time [20:00 Oct 5 2002 UTC].
    > 
    > The angular speed of the object was about 8'/sec, 
    > which corresponds to a satellite in a circular orbit 
    > of 3000 km.  An immediate problem is that an object 
    > with its angular size would be about 500 meters across.  
    > Even in a low (300 km altitude) orbit, it would have 
    > to be 50 m across.   I am not aware of anything "up 
    > there" that is near that size, so Earth satellite 
    > seems an improbable explanation.   Further out, the 
    > object would get to be large enough to be a trackable 
    > asteroid.  At aircraft altitude, I should have 
    > resolved it easily in my scope, and the resulting 
    > speeds are actually rather low for aircraft.  Birds 
    > that flew through my FOV moved several times faster 
    > than the object.
    
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