Re: [ATM] F5 Achromat Design Help

["Richard F.L.R. Snashall" <rflrs@rcn.com>]

Thomas Janstrom wrote:

>Cool, sure makes life a bit easier when you know what your working with,
>but I'm not really your guy for this type of design work, although I do
>like to dabble in it. Richard is way better than me!
> 
>
Thanks for the compliments!

I mentioned to Alfredo that I thought the color correction should
be a little redder.  I found that, when the minimum focus is near
the e-line, the two inner radii are roughly equal.  Using that, I
got (also nulling at the e-line):

Surf      Radius   Thickness    Glass
 STO    Infinity   -4.805649
   2     346.399        18.5    N-BK7
   3    -213.853     1.93836
   4    -213.853           6       F2
   5    -959.869     582.246
   6   -215.3733       0.011
 IMA      -157.1

The minimum focus here is actually at 547.198 nm. The visual Strehl
here is 0.5279 in the center and roughly down 2.1 magnitudes from
that at 10.4 mm from the center.  This loss will probably be larger
when the center is focused, due to the field curvature.

However, not going quite as far into the red:

Surf      Radius   Thickness     Glass
 STO    Infinity   -4.888782
   2     340.591        18.5     N-BK7
   3    -218.939       2.696
   4    -217.489           6        F2
   5    -997.916    580.3082
   6   -212.3232     -0.0007
 IMA        -158

The minimum focus for this is 535.395 nm.  The visual Strehl is up
to 0.5891 in the center.  It too is down roughly 2.1 magnitudes at
10.4 mm from the center.

For both of these, there will need to be a land on the F2 element in
order to get it into a 14 mm blank.
_______________________________________________
ATM mailing list http://www.atmlist.net/