Re: [ATM] [atm] how to test flat secondary mirror

["Bob May" <rmay@nethere.com>]

<<
Dear my friend, i enjoyed so much about the usage of flat mirror
, but i want to ask you if possible .,let me know how it is
usefull for testing the parabolic mirror ., is it possible for
you to tell me  with figure....and some  explanation.... how do
we  locate the mirrors  ( parabolic  and flat mirror ) in testing
procedure......
>>
Flat mirrors have the ability to change the direction of the
light path without affecting the shape of the wavefront, assuming
that the mirror is sufficiently flat, and thus bringing a focal
point out to where it may be seen by an obserber.
In testing, flats usually aren't used as such although something
related, a beamsplitter, is sometimes used in doing testing when
the source and resultant beams ned to be together.  In the case
of autocollimation of a refractor, for example, any difference in
the angle of the two beams says that the light travels different
paths  and these different paths end up giving errors in the
shape of the lens - the test being light coming from the tester,
going through the lens, hitting a flat mirror of large enough
size to reflect all of the light that came through the lens, and
back again to the KE.  A beamsplitter needs must be used so that
the two light beams are congruent to each other.
In completed telescopes, the flats are usually used to bring the
light out to the side of the scope so that the image may be seen
without getting the body into the light bath of the scope.
Thus, there is a need for both large and small flat mirrors.
Bob May
Due to the large volume of SPAM thaat I'm getting, add an open
square bracket to the subject line or my spam filter will reject
your post~
rmay at nethere.com
http: slash /nav.to slash bobmay
http: slash /bobmay dot astronomy.net
Replace the obvious words with the proper character.

_______________________________________________
ATM mailing list http://www.atmlist.net/