X hits on this document

Word document

Archives of an email list on the history of binoculars. - page 142 / 150





142 / 150

These values are closer to the Jena type O.144 glass than to other glasses in the 1902 publication and I believe that is in fact the exact type used for both of these prisms. The slight discrepancy in dispersion values (Abbe v number) is probably due to accuracy limitations in my measurement wavelengths. Someday I plan to repeat these measurements with a higher accuracy setup.

Note that modern Schott glass catalogs use a different wavelength for the nominal index of refraction measurement, Nd at 587.56nm Yellow Helium line, but the same wavelengths at F and C.

If anyone else has other data or measurements please let us know.

Steve Stayton


Subject: Zeiss prisms

From: <L.Helling@___ne.de>

Abbe used the new "specialy light and clear" Boro-Silikat-Kronglas from Schott for the first Zeiss binoculars.

Lothar Helling


Subject: 6x30 codes

From: "Prof GH Samuel" <g.h.samuel@___c.uk>

Fzg is not that rare a code: I have in my time seen about half a dozen 6x30's carrying it (and I own one whose optical quality is superb). However the serial numbers are always low: between 2000-4000.

Other 6x30 codes not listed in your last circular are:

clb: Wohler

emv: Hertel & Reuss

eug: Optische Prazisionwerke, Warsaw

fvs: Spindler & Hoyer

fvx: Beck & Sohne, Kassel

jxn: Helmut Korth, Berlin

I have personally seen 6x30 binoculars carrying these codes (or photographs of such binoculars). However by far the most common 6x30 codes are ddx and cag, but I have never seen these two codes on 7x50 or 10x50 glasses.

Geoffrey Samuel


Subject: Logistics

From: <mikedenmark@___ele.dk>

As a kind of answer to Mr. Tenenholtz view on logistics.

That is a classical dilemma...If you plan perfectly, everybody will have the best possible equipment at the appropiate time.

Only planners are human, and the world is too complex to be planned for.

In economics, I have heard it described as the inner friction of the system.

Friction is loss of energy and loosing something puts you at a disadvantage.

Document info
Document views324
Page views324
Page last viewedThu Oct 27 09:26:08 UTC 2016