C-11 + FR vignettes with wide field eyepiece

My 2" Pentax 40 mm 65 deg eyepiece vignettes visually in my old Ultima C11
OTA using the Celestron .6 focus reducer! I see a dark ring around the edge
of the field, so not the full field.
Any one has the same problem?
What wide field eyepiece would work with this set-up?

None. Get the Lumicon Rich Field Kit or the Giant Easy Guider. This will
not vignette.

regards

Joe

The Celestron focal reducer is designed to shrink a 2" image circle
into (drum roll) a 1.25" image circle. {2.0*60% = 1.2}

A 40mm 65dFOV eyepiece uses around 45mm of the standard 50mm (2") image
circle. You should expect this EP to vignette with this focal reducer!
In general, focal reducers are for people who don't buy 2" eyepieces,
or people who do astro imaging with small sensors.

The C11 has a 2.7" (+/-) potential image circle, so a giant easy guider
will capture enough image circle that after being reduced by 60% will
still be about as big as the image circle accepted by the 40mm 65dFOV
EP.

Mitch

J McBride wrote:
None. Get the Lumicon Rich Field Kit or the Giant Easy Guider. This
will
not vignette.

regards

Joe

Hi:

Perhaps. But you lose the field flattening of the Celestron f/6.3
reducer/corrector. I find, personally, that with the r/c in place I
don't need to use very long focal length eyepieces to get the field I
need. Also, while the 35 Panoptics is obviously vignetted in this
configuration, it's hardly "unbearable."

Peace,
Rod Mollise
Author of:_Choosing and Using a Schmidt Cassegrain Telescope_
http://members.aol.com/RMOLLISE/index.html

On Fri, 4 Feb 2005 10:25:28 -0500, "J McBride"
wrote:

None. Get the Lumicon Rich Field Kit or the Giant Easy Guider. This will
not vignette.

regards

Joe


They are also not corrected the way the Meade/Celestron f.r. are, what
you are getting is a $40 80mm achromat with the Giant Easy Guider.
-Rich

but the view is unvignetted and that is what the man was asking about. The
Lumicon kit works well for some people and not so well for others.

Joe