[APML] 10" f/4 first light

["William R. Mattil" <wrmattil@ix.netcom.com>]

Well,

After three weeks of rain, gusty winds, thunderstorms and countless
cloudy nights in the Dallas Ft Worth area I was finally able to collect
some photons with a new 10" f/4 Parks OTA. Some interesting points raise
a few questions though. I specified when ordering the OTA that it was to
be photographic instrument and specified a low profile focuser (JMI) and
gave them the dimensional data from the OAG and T ring. When I unpacked
the OTA I was surprised to see just how big the secondary was. Wow ....
big difference from the 10" f/6 <g> Makes collimation interesting as
well because the sight tube doesn't reveal the whole secondary to help
in alignment.

Question number one: When using this optically there is a significan
shadow in the EP from the secondary. Not as noticable on starfields but
Venus, Jupiter and Luna exhibited quite a bit. This was with a 26mm
Plossl (meade 4000). Does this sound normal given the criteria that I
gave Parks ??? I didn't see any vignetting through the cameras finder
and when I get the film processed the negatives/prints will be inspected
and comared to that of the 10" f/6 to see if any improvement in
illumination was achieved.

I had no difficulty getting a good focus with all of the normal goodies,
OAG, filters etc so this is a good thing. Ended up shooting some
Moon/Venus shots on a roll of Fuji SHQ100. Bracketed the shots as usual.
Tried a 5 minute guided shot of some stellar subjects, and while polar
alignment wasn't great guiding seemed reasonable (an untested
mount/drive was used) Still need to try and figure out the DSC's though
... :^)

Any comments would be most welcome

Regards

Bill
-- 
William R. Mattil	| Fred Astaire wasn't so great.
wrmattil@ix.netcom.com	| Ginger had to do it all backwards
(972) 399-4106		| and... in high heels.

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