canopus56 wrote:
"W. Watson" wrote in
:
snip
Anyone know where I can get the
required parts, or some other set of parts that will do the same?

Different setup, but you might want to take a look at Rick Evans imaging
train in Issue #7 of _Selenology Today_ at page 5. It uses a Rainbow
Optics grating with a Televue Powermate.

http://digidownload.libero.it/glrgro...logytoday7.pdf

The step-down ring approach is interesting. Haven't done it myself. Here
is a link to a Canon dealer with a product catalogue showing a number of
steps rings that could get you from 67mm to 49mm (T-adapter).

http://www.overlandphoto.com/pages/lensacc.html

I thought the "T adapter" thread size was 42mm x 0.75mm
and 2" eyepiece filter threads were 49mm x 0.75 mm...

(I still haven't figured out what the nominal size for 1-1/4" eyepiece filter
threads is supposed to be...)

-dave w