[APML]: Focal Reducer

[Tom Porter <Tom.Porter@digital.com>]

The Astro-Photography Mailing List
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I recently finished some test shots with my 10" f10 LX200 of the moon(32
arc sec).  I took the shots with and without my f6.3 focal reducer.
What I noticed was that without the focal reducer the photographic
coverage was slightly less (.5 x .72 degrees) than claimed by Meade
(.54x.78), not really surprising and not that far off.  I would suspect
that the coverage is dependent upon far back from the secondary mirror
the camera is mounted.

Here is what is surprising.  With the focal reducer installed the stated
35mm coverage is .86x1.24 degrees, instead what I received is 1.08x1.56
degrees, implying that the focal reducer is operating more like a f5
instead of a f6.3 (sure hope my math is right).  Any explanations for
this?  

Thought, I would repost this as I haven't received any thoughts or
possible explanations.

Tom Porter