Tass Lens Assembly

[Tom Droege <tdroege2@earthlink.net>]

I took a tass lens apart with the idea of doing something to prevent the 
second lens from the front from breaking in cold weather.

I gave up.  The lens tolerances are just too tight.  I could barely get it 
apart and then barely back together again.  I fear that if I slot the cell 
in which the second lens sits that it will expand and I won't be able to 
get it back in the tube.

OK, we will live with this problem.  Those of you with Mark IVs in cold 
places please look in the end of the lens tube from time to time.  If you 
see funny white spots radiating out from the edges of the lens then you may 
have a problem.

If too many break, I will design a new lens cell and get new lenses 
made.  Sigh!  I am getting used to doing such things.

The good news - I disassembled a V lens - is that all the faces are in the 
right order (now).

Tom Droege