To: atm{at}shore.net
From: Mark Suchting 
Reply-To: Mark Suchting 


At 07:31 PM 4/25/2003 -0600, Bill T. wrote:

>In defense of star testing, I have to say that I have seen several "at
>least acceptable" mirrors made using nothing more than formula polishing
>techniques augmented with only a few star tests.


I'd like to add that a Ronchi grating at prime focus on a star is a
perfectly valid way to final check an F6 or slower mirror before
aluminising.  Even in the presence of poor seeing, 1/4 wave mirror is easy
to see and improve upon. More use of a simple test like this may give first
time foucault test users an independent cross check on their mirrors.

~Mark

--- BBBS/NT v4.00 MP