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Re: [APML] light loss

To: <astro-photo@seds.org>
Subject: Re: [APML] light loss
From: Tonyhallas@aol.com
Date: Fri, 21 Sep 2001 00:35:13 EDT
Reply-To: astro-photo@seds.org
Sender: owner-astro-photo@seds.org

Roland,

   It's true that the large obstruction blocks a significant amount of light, but remember that it is in the center... most of the area of a mirror system is at the edges...

    When I compare the "speed" of this "f/8" to what I got with a telecompressed C-14 at "f/7.5" with a GEG, it is no contest. The larger secondary is more than offset by the complete illumination of the negative and the efficiency of the mirrors (no glass to pass through)... by the way, I did put 96% enhanced coatings on the mirrors. My baffle tube is 4.5" in diameter... a lot of light goes down that thing. My feeling is that this "clean" system is 1/3 faster than any SCT telecompressed to the same f ratio... maybe even a bit faster. And the quality of the image... no contest.
Besides, all the bright stars have groovey crosses! :-)

      Tony

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