a long time ago I told you the little story about my mysterious long refractor - see here :
Because of the fact that the objectiv was very long time at the optican Mr. Wolfgang Grzybowski, I do not know exactly the fl of this refractor. Once ago I supposed it must be around 1600 mm, because of the length of the OTA.
Mr. Grzybowski cleaned the optic, makes new spacers and adjusted the optics. Also he made an new frontring, because the original aluminium ring was a little bit to wobbly to hold the collimation stable. Now he had made a thicker ring on his lathe - a little disadvantage is the fact, that so the clear aperture is reduced from 101 mm to 98 mm. But thats no problem for me.
But now comes the big surprise ; the FL of this lens is 1732 mm !!!
In the mentioned old thread we have several ideas of the origin of this refractor : some parts are defitly made by Vixen ( OAZ, tube rings ).
BUT : which manufacture made an 4" f/17 FH objectiv ?????
The optic is superb, it has a very weak blueish coating ( MgF coating ? ), that can be an hint to the age of this lens.
I also supposed that the hole refractor was an ATM project.....but also the lens ???
Who will make an f/17 lens as an ATM Project ?
Do you have any ideas of the lens origin ? In the old thread the name Edmund was mentioned, but did they made f/17 lenses ?
The good thing : optic is superb ! To 250x I can not see any colour ! Only at madly 300x I can see a very thin dark-purple fringe. A very sharp and contrasty optic.
I'm very glad with this dinosaur !!!!
Because I dont know his origin,I called him the PHOTON refractor
Here are a few nwe pics from the actual state of my Setup :
Kind regards, Michael
Edited by AaronM, 22 October 2018 - 11:59 PM.