Paul,
Regarding use of the filters, I think you need about 59 mm set back distance from the FR to the CCD. As you have indicated, you have no hope of getting that by using the nosepiece with the 1-1/4 visual back attached to the rear of the FR - its just too long.
However, you may be able to use a filter drawer (Astronomik makes one) that adds only 20-22 mm to the optical path and can replace a portion of the variable T-Adapter. You may have to uses some T-Thread rings of 5, 10 mm sizing to get the needed set back though.
The added benefit with the filter drawer is that you don't have to dimount the camera to change filters. Oh, and others make filter drawers besides Astronomik - I believe Atik does and SAC does.
Regarding use of the filters, I think you need about 59 mm set back distance from the FR to the CCD. As you have indicated, you have no hope of getting that by using the nosepiece with the 1-1/4 visual back attached to the rear of the FR - its just too long.
However, you may be able to use a filter drawer (Astronomik makes one) that adds only 20-22 mm to the optical path and can replace a portion of the variable T-Adapter. You may have to uses some T-Thread rings of 5, 10 mm sizing to get the needed set back though.
The added benefit with the filter drawer is that you don't have to dimount the camera to change filters. Oh, and others make filter drawers besides Astronomik - I believe Atik does and SAC does.
Jim Thommes
Mak-Newt 152 mm
C8
Megrez II APO
Zenithstar 66 mm APO
G11/Gemini
ST8300M
Artemis285 Camera
Canon 350D DSLR
http://jthommes.com/Astro/
