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Old 28-02-2005, 05:17 PM
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MiG
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Join Date: Feb 2005
Location: Bentleigh, Melbourne
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Quote:
Originally posted by ving
so what happens if they are on your eyes? i'd have thought the effect would be the same(ish)
The power density is much higher after the binocs. Before binocs: assuming 50 mm apertures, 3927 mm^2 of filtering area
After binocs: assuming 10x mag = 5 mm exit pupil, 157 mm^2 of filtering area.

So each part is absorbing 25 times more energy if you use the filters between the binoculars and your eyes.

Now lets say you have a 100 mm refractor with a 5 mm exit pupil and an eyepiece filter. 400 times more energy absorbed per area. No wonder the bloody things break.