Re: [ATM] No fringes

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

The LED is good enough to see fringes BUT, that needs to be the
only source of light the eye is seeing as the LED really isn't
bright enough otherwise.
One of the guys in my omirrormaking group is doing a Houghton and
we'be successfully done fringes on the Foucault tester setup.
The LEED is a green one and the fringes showd up at any distance
from the tester of the lenses from it.  The video camera was
needed to bring out the fringes tho as the eye was barely able to
see them due to the fact that the room isn't completely dark.
Better is to use one of those new screw in flourscent bulbs  that
have a fairly decent set of lines for doing such work.  There
seems to be two different kinds of those bulbds, one of which is
pure lines while the other seems to have a broadband background
to it.
I'll also note that if you work at it, you can often get fringes
with a regular incadesceent bulb although they are fainbt and of
a violet and green nature.
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/