ATM ? about interpreting thickness

[Mel Bartels <mbartels@efn.org>]

Could someone enlighten me?  TIA

MEL:
         I APOLOGIZE FOR KEEP BOTHERING YOU ABOUT THIS SUBJECT. THE WAY
I
     SEE IT, THE THICKNESSES IN THE TABLE OF THE HOUGHTON TELESCOPE (AND

     MANY OTHER ARTICLES IN THE JOURNAL) DO NOT REPRESENT THE PHYSICAL,
     TANGIBLE THICKNESS OF THE GLASS. I GUESS -AND THAT IS MY QUESTION-
     THAT THE NUMBER -"D"- IN MILLIMETERS CALLED THICKNESS MAY HAVE
     SOMETHING TO DO WITH BOTH THE DISTANCES BETWEEN OPTICAL COMPONENTS
AND
     THEIR OWN THICKNESS, BUT I DON'T KNOW HOW TO READ THEM.

     THE HOUGHTON EXAMPLE:

                RADII OF CURVATURE              THICKNESSES

                R1  1286.81                     D1   16
                R2 -4810.34                     D2    3
                R3 -1286.81                     D2   12
                R4  4810.34                     D4  617.67
                R5 -1590.97                     D5 -793.84

     THERE MUST BE FORMULAS INVOLVING RADII, RELATIVE DISTANCES AND REAL

     THICKNESSES TO GET THESE "D" NUMBERS. RELATIONSHIP I FRANKLY DO NOT

     KNOW AND TRY TO FIND OUT.

     THANKS AGAIN AND BEST REGARDS, JORGE.


--
Clear skies, Mel Bartels
http://www.efn.org/~mbartels