Jaegers 6" f/10 "GJD" OTA Construction - Flint Element (Edge View 1)
 

The flint element for the Jaegers 6" f/10 GJD Refractor - Side 1 (Click to see an enlarged image.)

 
The uncoated flint element for the Jaegers 6" f/10 achromatic objective for the "GJD". On the side of the objective you can see a dater of "6/1/83". I presume this was the date it was tested in Mr. Jaegers' shop. There is also a series of numbers spaced with hyphens (9-9-12-3), which I am unfamiliar with. Perhaps a bit of research would help.