Re: [ATM] first light on a Lurie-Houghton

[Guy Brandenburg <gfbrandenburg@yahoo.com>]

Bob,
We got the wedge down to very close to zero.. We built a little gizmo with a dial indicator and kept at it until we were. Don't have my records with me here right now, but the wedge was very good, less than 2 thousandths of an inch overall.

Bob May <rmay@nethere.com> wrote: The two surface that neet to really match, you have done so, R1
and3.  These are the strong curved surfaces.  The other two can
be quite different and not seem to matter too much.  Plug the
numbers into OSLI and you will see that the R1 and 3 surfaces
will change the color correction drastically while the other two
surfaces won't hardly affect anything but the focal point.
If you having''t measured the wedge in the glass of the two
lenses, I strongly sugggest that you do so by the method shown by
Newwport Glass and also on my websitete for making lenses.  Any
wedge will shove the center of the lens from the center and thus
will make for all kinds of problems that you will probably
otherwise never figure out.  The wedge needs to be very close
to - and is best at zero.
I haven't investigated whether the corrector being tilted would
make for any nasty problems but, like anything, the closer to
square it is, the better off you would be.  I'd suspect thqt the
biggest problem would be lateral color problems followed by a
minor coma that will be even over the entire image plane.
Bob May



Guy Brandenburg, Washington, DC
My home page on astronomy, mathematics, education:
http://home.earthlink.net/~gfbranden/GFB_Home_Page.html
or else 
http://tinyurl.com/r6fh2

=============================
"The corroded and corrupt state of Saddam was replaced by the corroded, inefficient, incompetent and corrupt state of the new order," Ali A. Allawi concludes in "The Occupation of Iraq", newly published by Yale University Press...
=============================
_______________________________________________
ATM mailing list http://www.atmlist.net/