Hi Brian,

What you have is a big simple eyepiece which give an erect image. When you were placing that DCC element just inside the focus of the mirror it turned outward the converging rays of light into parallel rays so that your eye could focus the image. That image would be too low a power and to chromatic to be of any use.

The curves as you describe them whould be to steep to make any form of corrector that I could image for that mirror. The pair may have went together as a form of condenser.

I do not know of any SCTs that use as slow a primary as f:3, most are f:2. If that were either a SCT or Mak primary then it would be a sphere and not suitable for any scope of reasonable construction. Look up info on a lensless Schmidt Camera. Stopped to a 6" f:4 might make a nice camera.

An 8" newtonian would require too big of a secondary and have too much coma to be practical.

In all probability, except for the lensless Schmidt, you have nothing of value in the glass unless refiguring or regrinding is involved.

Have Fun Experimenting,
-Rick

• Now if I could - crockett - November 11, 2001 - 06:13 UTC