M75C Elbow Telescope
Posted 03 November 2013 - 01:02 PM
I remember Jaegers selling these for years and years.
Really too heavy for most scopes these days, but I may find a use for it. Just fun to see one again after several decades.
Anybody else ever use one of these as a finder, back in the old days?
Posted 03 November 2013 - 02:30 PM
I wonder if he ever took it apart and cleaned it?
Posted 03 November 2013 - 02:48 PM
It looks amazingly clean on the interior, despite the worn external appearance. A few dust flecks on the reticle.
The focusing action is smooth.
Posted 03 November 2013 - 04:29 PM
Posted 03 November 2013 - 05:46 PM
Posted 03 November 2013 - 05:49 PM
Posted 03 November 2013 - 05:51 PM
Chuck - The M75C is an interesting scope for sure. A M75C I have needed to be disassembled for cleaning - so I had a chance to examine the eyepiece lenses. The M75C ocular is a two achromat arrangement that would likely be called a Plossl today. While the lenses were out, I compared them to an old 28 mm "Kellner" purchased from Edmund 40 years ago. The lenses seemed identical and would even exchange in the barrels. Quoting from page 129 of Edmund Catalog 651 about their 28 mm "Kellner": " . . . Has the same set of lenses used in quality military telescopes. We put them into a new metal cell and extension for 1 1/4" holders . . . ". This Edmund "Kellner" was very popular and showed the "floating image" effect like the RKE 28 mm does now. I recall using one for my first look at Jupiter's bands through a 6" f/8 Newtonian in 1960 - I was hooked! In the original M75C ocular mounting there is a wide metal rim around the eye lens (check your scope), so no "floating" effect is seen when viewing with the elbow scope. - Bill
Thanks for the background info, Bill. I'll check it out next time I'm down in the shop and look for the eye lens rim.
Posted 03 November 2013 - 07:25 PM
Posted 04 November 2013 - 05:35 AM
my dad bought it for me for the equivalent of $6 in the early 1980s.
i was amazed at how clear the stars were through it, compared to naked-eye. this was before i discovered that i needed specs...
mine was still at home, but had completely corroded and froze up. my mom donated it to the local museum.
Posted 04 November 2013 - 08:59 AM
Looks like in both cases, they were originally used on anti-aircraft guns.