My new "simple observatory" is now online with my trusty old 2008 Celestron-11. As I've gotten to the age of 78, it has become a rare time when I feel like lugging the 35 lb. OTA out onto the permanent pier Losmandy G-11 mount. Then at the end of observing much of the entire assembly was returned to the nearby garage. Such a hassle! The mount on pier would remain outside, covered with a Telegizmo 360 and plastic garbage can.
But I remembered a prior slide-off roof observatory I had nearly 40 years ago, which inspired me to make another one of 8 X 8 feet size. So here is what it looks like now.
Presently the roof slides off using human muscle power. But soon to come is a split-reel winch that will slide the roof open or closed. It will be powered by a 20 volt hand drill using a worm gear set, a pulley and 3/16 inch steel cable.
This shows the Celestron-11 in its home storage position where it will clear the roof as it is slid closed.
Last night I had an enjoyable session with a bright, near full Moon observing some Spring globular clusters. Such a joy to use the big SCT under such conditions.
Late Edit:
Schmidt-Cassegrains have their strong and weak points. Pluses are light weight and short OTA for a given aperture. When thermal issues and accurate collimation are given due attention, they can perform quite well. Also an SCT has a relatively large back focus capability, which is an aid for imaging or bino-viewer use. While refractors can out-perform an equal aperture SCT, few refractors exist in the 8-inch and above size. When I piggyback my AT115EDT APO refractor, sometimes it wins on double stars. Other times the big SCT wins if seeing allows. For light gathering power the bigger aperture excels.
Among the negatives are the need for very accurate collimation for best high power performance. Also the fact that light traverses the interior of the OTA three times before coming to focus gives opportunity for thermals to degrade the image. And yes the obstructed aperture reduces contrast. Some users report variable quality in the execution of the optical design. My experience (C-5, C-8 & C-11) has shown reasonable quality commensurate with purchase price.
I don't want this to be a vehicle for the sometimes endless debate about the merits (or demerits) of Schmidt-Cassegrains. I'm just stating some of the reasons why I'm so pleased to have my own Celestron-11 on a nice go-to equatorial mount housed in observatory. It makes me a real "Happy-Camper".
Clear Skies,
Russ
Edited by Rustler46, 23 May 2024 - 12:50 AM.