Help!!!!

     I am searching for software that does optical ray  tracing.  Most
     any  language  would  be  OK.  Being  able to get my hands on the
     source code would be wonderful,  but not a requirement.  I have a
     BASIC  program  that  performs  meridional  ray  tracing that was
     published several years back in Sky & Telescope  but  it  is  not
     very well documented, in fact, it's not at all documented! It was
     translated from FORTRAN to BASIC back in the days when 16K of RAM
     was  a  lot  of  memory  and  REMark  statements  were out of the
     question when writing for a micro. Anyway, I'd be more than happy
     to exchange PD software,  or pay the going  price  for  a  decent
     optics program. Contact me at Fido 138/0.