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Re: [APML] Question about SCT and Giant Eazy Guider
Hi Wei-Hao
The baffle tube is more than wide enough to provide an unvignetted field on
a 35 frame - the restriction in the light cone is caused by the 3-1/4" to
2" adapter -- however this is removed when you use the GEG. Depending on
the focal reduction mode used, there can be little or no vignetting when
using the GEG. The unvignetted field is much larger than with any other
OAG I have used with an SCT. Guide stars are easy to find. Please see the
following article which I hope will answer your questions:
http://www.astrocruise.com/geg.htm
--Philip
At 23:15 19/06/2004 -1000, you wrote:
>Aloha,
>
>I have a question for people who use SCT and Lumicon Giant
>Eazy Guider.
>
>I heard that the illuminated areas of SCTs are limited by
>its baffle in front of the primary and is not much larger
>than the 35mm camera frame. Is this true? If yes, what's
>the advantage of using a large off-axis guider such as the
>one made by Lumicon? The field of view is small anyway,
>right? In addition, if the illuminated area is small, how
>can the prism of such large off-axis guider access the star
>light? (I assume that the prism locates near the edge of
>the giant eazy guider.)
>
>Thanks for answering.
>
>Wei-Hao
>
>
>______________________________________________________________________
>Wei-Hao Wang :)
>
>Institute for Astronomy at University of Hawaii
>
>Address: Phone: 808-956-9867
>2680 Woodlawn Drive Personal Website:
>Honolulu, HI 96822 http://www.ifa.hawaii.edu/~wang
>______________________________________________________________________
>
>
>
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Philip Perkins
<pgp@astrocruise.com>
Wiltshire UK & Luberon France
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