Are you ready for the second installment of "bafflemania"? Lets go!
Now that my favorite "test target" is baaack! This morning an opportunity for Jupiter GRS w/o the otherwise ever present jet stream presented itself. I now have a baseline with two control scopes. The key objective is to increase the quality of visual observing by changing the way baffles are done in an otherwise ideal (1/8th wave tested) sample.
The ability to function close to that of an known good long achromat, in the form of useable focus in difficult conditions (low altitude) on known low contrast features (e.g. actual use case) is the prime objective.
Secondary baffle’s wider, lower opening is 1.4” OD (0.042” thickness except with inside chamfer 0.160” long down to 0.30” thickness - mine has some flashing left on - appears to be a styrene plastic like the primary baffle). Top of baffle, where cemented to mirror is 1.25” OD. The baffle is 1.625” long. There is a bearing surface enlarged “land” against the mirror where glued to it. This ID is 1.090” and is the “stop” that determines the effective size of the secondary mirror. If one could “trim” the secondary mirror spot back and insure that the edge wasn’t specular (like with chemical milling) this would be the smallest CO possible.
(FWIW, Questar’s have a different than corrector radius secondary with a black ring around it. That ring acts as a stop in the same way.)
Both baffles came off by applying anhydrous isopropyl alcohol to the glue seam. The glue appears to be a clear film, which might be styrene model glue. Both plastic baffles have a smooth finish of medium gloss, and do reflect incident light well.
Using the light bulb test, the upthread prototype cone did not pass light around the secondary, even when the corrector was at maximum extension (screw thread at/beyond stop).
The true CO is 36mm. Without the baffle it becomes 32mm. if you reduce the spot it can be made to be 26mm. Is the reduction from 40 % to 36 % worth this trouble? Is masking then trimming the spot to as little as 27mm (size of the primaries hole) to get to 30 % worthwhile? We’ll find out. (Note, it's very likely that the stock baffles reduce the aperture of the C90, from the optical measurements I've made.)
No telescopes were maimed in the making of this post. Kids, don’t try this at home. Proper mathematics and technique were employed before taking action, and an objective criteria to measure has been and will be used to gauge visual results as the scope would be used.
Perhaps if it works out, it might be worth a DIY thread. But only if it works out well. Both baffles have been kept and the scope can be restored.