ATM RE: Thomas O'Hara and his pursuit of the 40"- er (Wright Newtonians)

["Sidor . Kurt" <KSidor@drc.com>]

A few years ago Thomas O'Hara was actively writing to the list working out
his plan to build the "ultimate" 40" fast visual scope that he had always
dreamed of.  His original plan was to go with a Wright Newtonian design
utilizing a Schmidt corrector plate and an elliptical primary mirror.  In
fact he soon discovered that if he built it it would have been the world
largest Wright Newtonian (if I remember correctly).  About a year before
this I had inherited an unfinished 12" Wright Newtonian from an elderly
family friend who had been making it of and on since the late 40's.  Being
unfamiliar with the math of Schmidt curves Thomas helped me out with a nice
OSLO file that he made in his designing of the proposed instrument.  With
Tom's file and a spreadsheet I wrote in Mathcad I was soon able to scale his
design size to fit mine and re-enter the Schmidt curve polynomial
coefficient into OSLO and have my design simulated!  Without his advice and
gentle assistance I'm not sure I would have gotten it done as nicely any
time soon.  I'm still building up the courage (and experience) to tackle the
Schmidt corrector but I now have confidence knowing I got the prescription
right!  Thank you Tom!!!!   Tom steered away from the Wright Newtonian
design due to the complexities in making that LARGE Schmidt corrector he
would have needed, and chose instead to pursue the Richey Chretien design.
Personally I think he made a wise choice but am forever grateful for his
expertise and assistance in the design of Wright Newtonians.

Thank you Tomas O'Hara, we will miss you!

Kurt Sidor
Mechanical Engineer
Dynamics Research Corp.
Encoder Division

P.S. If anyone is interested in Tom's Wright Newtonian OSLO file feel free
to write me, I'm pretty sure he'd want me to share.