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Old 01-05-2012, 06:31 AM
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SkyViking (Rolf)
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Join Date: Aug 2009
Location: Waitakere Ranges, New Zealand
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Hi Peter, the central obstruction is indeed a frequency filter but it does seem to affect a telescope's ability to resolve contrast.

There is a fairly comprehensive analysis here: http://www.telescope-optics.net/tele...bstruction.htm

There is also Thierrys Legault's page here: http://legault.perso.sfr.fr/obstruction.html
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