[ATM] refractive index of air

[Dominic-Luc Webb]

On Wed, 8 Aug 2007, Richard wrote:

> Strange, I've not come across the Norman test before and that's twice
> I've heard it mentioned in couple of days.

It is wonderfully simple, obvious and clever. When I first read
about this test, I nearly banged myself in the head to wake up
after (apparently) years of sleeping. The Norman test was
specifically dubbed "Norman test" in that S&T 1957 publication,
in which it was commented by the editor that none of professionals
in optics they could ask were familiar with this test described
by Burt A. Norman. There can be some confusion regarding the
citation, as the article was "conducted" by Robert E. Cox. I
presume Cox worked for S&T at that time.

For those interested in Catadioptric systems, the Norman test
described on pages 38-40, can be taken together with another
article by Burt A. Norman in that same issue on pages 96-99.
This article, again conducted by Robert E. Cox, describes a
design for an 11" aperture Maksutov with two configurations.
One has Newtonian focus with a diagonal mirror and the other is a
Cassegrain focus utilizing a secondary which was tested according
to the Norman test described on pages 38-40. It is clear this is
the basis for the Mak Club correctors we have discussed previously.
I finally found that issue and made copies of both. The design
for the Mak has what appears to be a complete prescription. I
am slowly piecing together an Osloedu file, and yes, I have one
of the original 11" Mak club correctors.

Dominic-Luc Webb