Re: ATM Refractor reverse engineering

["Frank Ward" <thewards@mindspring.com>]

Try getting the specific gravity of each element
and matching it against the catalogue s.g.

FW
Atlanta,GA
----- Original Message ----- 
From: <jrh@nofs.navy.mil>
To: <atm@shore.net>
Cc: <jrh@nofs.navy.mil>
Sent: Friday, August 10, 2001 6:46 PM
Subject: ATM Refractor reverse engineering


> 
> I have a 10" f/10 refractor made from a Thompson Optical 
> Company collimator lens.  Images at high power are not 
> very good.  I am trying to model this doublet, but I have 
> not been able to determine the glass type.    
> 
> I have tried Dan's technique of measuring the refractive 
> indices, but the strongly curved surfaces seem to interfere 
> with measurements.  I have been told this lens does not use 
> standard glass types, and this seems correct.  So far the 
> closest combination I have tried is SK5 and BASF1, but this 
> does not give exact results.
> 
> I want to model this lens to get a better feel for aberrations.
> 
> Any ideas about determining glass types?
> 
> Thanks,   
> Joe Hobart
> Flagstaff, AZ
>