ATM Refractor designing

[Bill Marriott <btk@pacbell.net>]

Hi folks;

Well, I've decided to bite the bullet and dive into the world of making
an achromat, since I currently do not have an optical project to suck up
my limited spare time...

I have at my disposal, with much thanks to Mark V. the following glass
to play with.

#1 a 6.25" dia Bk-7 blank, 1"+ in thickness

#2 a 7" F2 Blank, .8" thick

#3 a 7" SF6 blank 1" thickness

I will be edging the 7" down to match the Bk-7 diameter.

I have been doing a little fooling around with the lens design program
that came with R&vV, and initial results seem to show that a doublet
using the F2 works out better than using the SF6, which is not what I
thought would be the case, but then my experience in designing achromats
is very limited. However, the max value for LA still is above 1mm, and I
would like to improve that if possible.

The following values were used.
Bk-7
Nd 1.51680
Nc 1.51432
Nf 1.52237

F2 
Nd 1.62004
Nc 1.61502
Nf 1.63212

SF6
Nd 1.805182
Nc 1.79609
Nf 1.82829

F/d = 15

As time permits I am going to see how far I can get in OSLO lt, but if
anyone has any comments as to how to maximize a design using either of
these flints, I would appreciate some input

TIA

Bill Marriott
btk@pacbell.net
http://www.starlightoptical.com
telescope and optics stuff