We need specifications for an AeroJet Delft lens. It is an f/1.5 with
a 12 inch focal length (possible 30cm) and
its serial number is 76749. We think it is an old reconnisance lens.
It also has the markings "45AG". We are using it for a photometer
experiment. We need to know the number of elements, the type of cement
or "o" rings used, the temperature rating and most importantly, the
optical properties of the lens. Thank You.

Hello Coppergarden,

I've not been able to locate much information yet, but I'm
advised that the lens is quite likely to be be listed on
the CD-ROM:

"Wright and Wilkinson's LENS COLLECTORS' VADE MECUM"

Hope this helps yourself or researchers find the
information you seek.

Best regards,

gan.

Thanks Gan, I'll add that clue to my list.

Further information;

When the lens was likely made, the whole company was called
Aerojet-General & was a subsidiary of General Tire & Rubber Co; all
their sites were divisions; but in the 60's the company split up into
a number of smaller independent companies.

It's been suggested that it would be quite unusual for such a lens to
be used for aerial reconnisance. Someone I approached for advice
suggested it could be a 'wide field star map lens', i.e. in normal
operation the lens would look up to the heavens rather then down on
the earth.

I'm told that such a lens would have an original cost of more than
$30,000 in mid-1970's money, and that it would be likely to contain at
least 8 elements in order to provide correction for chromatic &
distortive aberrations, etcetera.

If I turn up anything further, I shall post again.

Good luck,

gan.

Thanks again Gan,

    That's very interesting. We didn't know about the General Tire &
Rubber Co. And we always assumed it was a reconnisance lens. That it
was possibly designed to look up is a very interesting possiblity,
especially given our application.
    Some other bits of information that may or may not be relivant are
that the lens is slightly radioactive... which means it's probably
made from a glass containing a bit of Thorium. And that it may have
been designed to be used with a field flattener near the focal
point(this based upon our analysis).
     The plot thickens!

        KM

We have reason to believe that the lens was possibley designed by James Baker. KM