Yes, I did complete 2 each 24 1/2" f/6.2 SCTs way back when. They were designed by Mike Simmons for me. They had a 7 1/2" diameter focal plane and one had an 8X10 film back astro-camera built for it with integral of-axis guider port. The standard included cameras were my custom 4x5s w/off-axis guider port and a set of matched vacuum film holders. I only took 4x5 film images during testing and they were sharp to the edge. Still have the negatives. Customer taken images have been in S&T.
The primary was a Zerodur sphere of 25 1/2" diameter. The secondary was a 11" diameter Zerodur hyperbola (fairly strong) null figured by itself. Focusing was via radio control movement of secondary mirror. There was a large 2 element corrector lens group between the primary mirror and the focal plane. This design was complex since the Schmidt plate was 3/4" thick with a 7" hole and had 3 times the optical asphere of a typical f/10 SCT corrector. Tom Scott was the finishing optician who did the difficult corrector null figuring on both. To even get to a starting point he had to use his back pocket comb coarse bristle end as a Ronchi ruling to even see where to start on correction! He tore out his hair working it for many months and wanted to give up (without pay) being only able to get to within 1 wave of correction at best. His efforts to get closer erased the total correction. Both customers were $3/4 in by then and the OTA/mounts machine work w/paint was just waiting on completed optics. I offered Tom a sizable $ gift (either way) to leave or stay on it. He agreed and I was then able to enlist Dave Dodgen (not to mixed up with son Rod) to walk him thru necessary Schmidt plate figuring technique over the phone. With Dave's gracious help Tom then made new progress and null figured both optical systems to spec. with big smiles all around.
The only other opticians working on the glass for these 2 SCTs were Norm Cole, Brian Lizot and Joe Appels in that order.
The original #1 customer came out one night to test his finally finished SCT at my place in White Rock (Los Alamos) N.M. Since the scope would not split Sirius for him that night, he wanted a refund!!!! He was from Lebanon and, well he used me with this pawn. Since I knew the real value of the instrument I agreed that same night to refund his $65K less a 20% fee. He was fine with that since he wanted the funds for a Duncan Donut franchise down in ALBQ, NM. My wife/partner was not so fine with that night. His first name was Kamel. Never saw him again after years leading up his canceling.
The next SCT went to Helena, Arkansas and the #1, I later sold to a previous customer up in Crestone, Co. with incredible sky. He got a nice portfolio of color 4x5 film images with it. Years later he upgraded my cast aluminum AstroWorks mount with a much more robust all steel GEQ that was said to be by it's maker "able to hold a Volkswagon" (beetle?...) Just after transferring the 24inch OTA onto the new mount, that mount separated (as in broke in two) at the RA/Dec junction. The Schmidt plate and secondary shattered on the concrete floor and all that was left were the primary and 2 element lens corrector for the focal plane. The mount maker later walked away on him, but luckily this customer's lawyer son got all over the home owners insurance company enough to where they finally paid out. So #1 is dead. As far as I know, #2 still lives on in Joplin, MO.
In almost 40 years of custom telescope making these 24 1/2" ers were a real test for me during the time. Later on I had a similar experience with the three automated C28" f/3.2 prime focus CCD astrographs made. Making all those one-of -kind new design telescopes sure kept me on my toes along with the 12" f/5 series Astromaks included in the mix! Never easy stuff! Not always easy customers. Not always simple installations for me. Lots and lots of stories though. The all white scope is sn2 24 1/2" SCT.
Jim Riffle, retired telescope maker from ASTROWORKS