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
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