Posted by Bob Campbell (134.253.26.9) on January 06, 2003 at 10:38:45:
In Reply to: Bob Campbell how is your Swayze Mirror? posted by Lawrence Regira on January 03, 2003 at 21:39:06:
Hi Larry
Thanks for the inquiry. Steve seems like a great guy. I got very rapid turn-around
from Steve and Spectrum Coatings, sent it off at the end of
August, and had it back early Oct. He concured
that it was overcorrected, and gave me a step by step
description on what he had to do to bring it up to
a good standard. However, I never got
any specific numbers on it since he doesn't determine
the Strehl ratio. He just indicated that I would be 'very
pleased' with it. Spectrum did a beautiful job on both the
primary and secondary.
After that long-winded preface, I have to tell you
I have yet to get it under the right conditions to see much of a difference.
I am working very hard to get **perfect** collimation
as well as an excellent night of seeing. The f/6 should
not be too sensitive to collimation, but I
want to be sure; right now, the New Mexico nights
are often very transparent, but the seeing has not been too good.
The best planetary performance I got with the old
figure was right at sunset before the atmosphere
had a chance to cool down much; to reproduce that
for Saturn or Jupiter I'll have to wait another
month or so so they are closer to overhead at sunset.
Sorry to beat around the bush, but I would have to
say I can;t tell how good the mirror is yet.
How did yours turn out?
Bob
: I had my 12.5 inch mirror refigured by Steve in June but unfortunately I have not yet mounted it back on the scope. I still have a few things I want to do to it. I purchased a low profile focuser from MoonLite Telescope Accessories and a CatsEye collimator this Christmas from Jim Fly. I want to move the focuser further up the tube. I also will need to extend the old tube. I have an article in an old 1992 issue of Sky and Telescope where a tube is extended using 1/8 inch masonite. I think when I do finally get my scope up and running it will perform better with this setup. Steve was surprised that I was satisfied with my old mirror because he found it was overcorrected in the middle areas and undercorrected towards the edge. I think due to the placement of the secondary in the original Cave setup, the outer inch or so of the mirror was not being intercepted by the 2.6 inch secondary in its original location. I read an online article stating that you should be able to see the entire mirror and then some when you view your secondary through the eyepiece holder. I know in the old setup this was not so. So, basically I was working with about a 10 inch overcorrected mirror all those years. I am also thinking about painting the tube black. I was reading on Carl Zambuto's forum where he thought a black tube was best. I sure do a lot of reading!
: Lawrence Regira