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Old November 22nd 07, 05:19 PM posted to alt.binaries.pictures.astro
George Normandin[_1_]
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Default Astro - Comet Holmes - USM.jpg (1/1)


"Rick Johnson" wrote
.......
If I rebuild my 6" f/4 it would work. Right now the tube is old and weak
where the spider sits allowing flex that causes it to lose collimation
just by slewing 40 degrees. A new fiber glass tube and better spider
should do the trick if the coma reducer for the STL series does its job.
I've not seen or heard much about it........


Rick,

I have two friends who bought an old Cave 6-inch F/4 Newt tube and
replaced the focuser with a Moonlight duel-speed unit. They use the Baader
coma corrector and it works great. However they are using relatively small
CCD chips compared to your STL-11k - an old Starlight Xpress MX-716 and
another camera (forget which one). I like the idea of trying a short focus 6
or 8 inch Newt F/4. Allen Chen has a home-made 12.5 inch F/4.5 with a FT
focuser in place of the secondary mirror. He uses a large chip and Baader
corrector with great success. Unfortunately I don't think the design would
scale down because the camera would take up too much of the field.

George N