From: "Jim Miller" 
To: "John Sherman" , "ATM"

Reply-To: "Jim Miller" 


Hi John

I'll be the first to admit I'm not a seasoned observer, planetary or
otherwise. I do have good vision with glasses but prefer to observe without
them however. My eyepiece collection consists of Nag31, 13, 7, 5 and a
Pan24. I'm planning to fill in with Nag11, 9 and probably a 3.5. I
previously owned a Nag16 but found the 10mm eyerelief to be too short for
my taste after using it for a year.

Every scope has tradeoffs and each has to make their own choices. You can
see my priorities on my website at www.jtmiller.com.

I knew at the time that one thing I would be trading off is eyepiece
selection with an f/4 since it is very demanding on eyepieces due to the
steepness of the cone of light. On the other hand I absolutely love the
Nagler series ability to provide magnification, sharpness and a immersive
feel. For me it provides context to the primary object of interest in the
central portion of the field. I'm more of an art lover than scientist when
it comes to astronomy.

The simpler eyepieces you mention below I'm sure work well for slower
scopes but wouldn't fare well in an f/4 scope even if equipped with a
paracorr due to aberations induced by the steep cone angle.

As far as optical benefits I suppose the only one I know of is that it
offers a wider true FOV. I get about 1.2ø with the Nag31 and the Paracorr.
Exit pupil with the same combo is about 6.7mm. My mirror was done by Steve
Swayze so I never really worried about the difficulty of producing it.

Good luck with your scope selection but don't fret too much about
optimization of any particular parameter. You'll enjoy using what ever you
get as long as it's in the ball park much more than not having it due to
excessive analysis. And I'm sure it won't be the last scope you own!

We used to live in southern NH in Derry and Hollis for about 20 years and
skied and hiked in the Franconia area. Wonderful area!

Best of luck

jtm

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