Re: Sun Outage simulation

From: Tom Wagner (sciteach@mchsi.com)
Date: Sat Nov 01 2003 - 11:52:17 EST

  • Next message: Ted Molczan: "DMSP F16 elements"

    Does anyone know if "irradiance" is a factor in limiting resolution when
    looking at a FILTERED sun with the eyes?  How about when looking at the
    moon? Is it a problem when using a camera with film or when using a digital
    camera?
    
    Two definitions of irradiance: the apparent enlargement of a bright object
    seen upon a dark ground, due to the fact that the portions of the retina
    around the image are stimulated by the intense light; as when a dark spot on
    a white ground appears smaller, or a white spot on a dark ground larger,
    than it really is, esp. when a little out of focus.
    
    Tom  Iowa  USA
    +   +   +
    
    ----- Original Message ----- 
    From: "John Locker" <john@satcom.freeserve.co.uk>
    To: <SeeSat-L@satobs.org>
    Cc: <dsat@smartgroups.com>
    Sent: Friday, October 31, 2003 6:06 AM
    Subject: Sun Outage simulation
    
    
    > Hi all ,
    >
    > During the early part of this month we went through the autumn sun outage
    > period.
    > On the odd occassions we had clear skies here I tried to check the sun 's
    > disc for
    > any sign of geosats using filtered high magnification . With each bird
    only
    > having an angular size of 1/10th arc second I didn't really think I would
    > see anything....and I didn't!
    >
    > When scanning the sun's disc I was looking for a tiny cluster of perhaps
    no
    > more than an arc second , which might represent seven satellites in a
    > group.What I didn't appreciate was just how spread these birds would be.
    > To demonstrate this , I have merged two images together , both taken with
    > the same lens setup , same FOV .The first a simple fame of the sun , the
    > second a night time exposure of the Astras.The result...instant outage .
    >
    > http://www.satcom.freeserve.co.uk/geos.htm
    
    
    -----------------------------------------------------------------
    To unsubscribe from SeeSat-L, send a message with 'unsubscribe'
    in the SUBJECT to SeeSat-L-request@satobs.org
    List archived at http://www.satobs.org/seesat/seesatindex.html
    



    This archive was generated by hypermail 2b29 : Tue Nov 04 2003 - 08:33:52 EST