Here are two of the hybrid diagonal options (0.965 to 1.25 in.), as mentioned above. A 0.965 in., original equipment (OEM) prism, star diagonal is included for perspective. In the middle is the GSO and the lightweight plastic one on the left is from 'Scopehed'.
The GSO version is also offered as an Amici prism model for correct image (RACI) viewing. The GSO model shown ($32 shipped from Agena Astro) is the mirror, star diagonal and gives the standard reversed image. It has the stepped barrel that allows its use in 1.25 in. visual back focuser tubes. The one I have came very well collimated, although, as mentioned previously, it can have an in-focus problem with some scopes (stated in its description on Agena's website) and I found this to be true in some of my 0.965 in. scopes.
The 'Scopehed', mirror star diagonal's housing and 0.965" barrel are plastic, as mentioned earlier by JohnR (post #12). However, its very light weight can be an advantage, especially in the .965" scopes which use the split tube end & spring ring retainer, as mentioned by DeWayne (post #8) instead of a threaded, visual back. I have two of these, and now they are $11 ea., shipped from 'Scopehed's' 'Telescope Warehouse' in Arizona and the shipping was fast. [ I was unable to find the 'Scopehed1' Ebay page mentioned by JohnR, but it must be there since I have bought from that site before] One was nearly perfectly collimated and the other is very close. Both give a good image and there are no in-focus travel problems with this diagonal in any of my .965" scopes. Not too shabby for only $11.
There is also the 0.965 to 1.25" adapter, mentioned earlier above as the "Fireball" (aka 'Blue Fireball'). At least three versions of this adapter exist and I have two of them. One is a two part, aluminum body (w/made in Japan sticker) with a chrome plated, threaded brass barrel and the other is a one- piece unit of machined aluminum. Each has a single set screw and the fit of both screws is on the sloppy side. The depth of the eyepiece socket on the one-piece unit is shallower and allows focusing to get just that little bit closer in when running out of in-focus travel. The eyepiece socket's top lip of the two-piece unit had to filed down to allow the eyepiece to get in closer to focus. Of course, if the eyepiece has a long barrel, bottoms out in the socket and is protruding out of the top of the socket, well, then it is irrellevant.
- Mark J.D.
Edited by Veridian, 05 November 2023 - 09:06 PM.