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#1
February 6th 04, 12:03 AM
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A question about indoor star testing
Well the weather has been so lousy here lately that all I have to look
at with my Orion 80ED is an artificial star. The problem is that it is only about 20 feet away. I know that this introduces spherical aberration but I'm uncertain weather it is undercorrection or overcorrection that is introduced. Does anyone out there actually know how much SA is introduced with an 80mm f/7.5 scope at that distance? Thanks 
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#2
February 6th 04, 01:01 AM
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A question about indoor star testing
Does anyone out there actually know
how much SA is introduced with an 80mm f/7.5 scope at that distance? Thanks Depends on the design. If it was designed with null or negative coma, it will look undercorrected. If it has slight positive coma, then it will look properly corrected at close range as well as far. I would guess that it will show 1/2 wave or more under at 20 ft. RC
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#3
February 6th 04, 01:01 AM
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A question about indoor star testing
Does anyone out there actually know
how much SA is introduced with an 80mm f/7.5 scope at that distance? Thanks Depends on the design. If it was designed with null or negative coma, it will look undercorrected. If it has slight positive coma, then it will look properly corrected at close range as well as far. I would guess that it will show 1/2 wave or more under at 20 ft. RC
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