GSO RC 10" - help please!

[paulobao]

Hi,

I'm from portugal and I did not post here for a while!

I have a Tak FS102NSV fluorite Apo and a QSI532WS (KAF3200ME) that I use for photo and a small Tak FS60C and a QHY5 as a guiding system. Graeat combo, no problems with guiding, neither colimation and that stuff. But my passion is astrometry and photometry so my OTA needs to be a larger one. Since I never had other telescope other that APO refractors and I want to go with a much greater diameter I thought in a catadioptric tube (a SC or a RC). My question: what should I gain with a RC10" (GSO) over my small razor sharp Tak FS102 and what should I expect to loose? I have a almost new C11 from a UK astronomer waiting for me (?) but I don't know much about SC too!

Could someone help me please?

Regards,

paulo

[el_draco]

Can't comment much about the R.C. because I dont have one but I am told they are anything from "ordinary" to "great" depending on how much you are prepared to spend.

Quality of the optics is the key, as alway, and a very good quality scope costs a lot. The GSO R.C.s are good, but they are mass produced and so the quality is somewhat less than perfect. I have heard that they are harder to align and the bigger central secondary obstruction can be an issue. The first series released had a problems with focusers according to the grapevine.

I use a C11 on a Losmandy G11 and its a pleasure to use, but it also has issues around primary mirror movement and smaller F.O.V. I added a good quality electronic focuser so that I can rough focus using the "very ordinary" focusing knob on S.C's and then fine focus electronically. Its a good arrangement. I am about to start imaging with this system so I can't comment alot about the imaging side of it yet but if the visual results are an indicator, I'll be happy. A casual look on the net will show you a wealth of excelent C11 images.

You also have the option of adding a "Hyperstar kit", (U.S. $1k), to the C11 giving it an F ratio of about 1.8. You cant use it for visual observing in this configuration but the photographic results are pretty amazing.

Visually, the C11 is great and easy enough to move around if you are careful. I can see detail in most DSO's with my system but some of the larger objects, like M42, wont fit in the F.O.V. of a low mag eyepiece.

Planetary detail is excellent and I get the "walking on the moon" feeling when I go there. I have just picked up a Powermate and hope to try that out soon.

Of the SCT's, the C11 seems to be the best. Meade has been getting a lot of bad press for variuos reasons, but most users seem to like the C11.

Hope this helps

Rom

[Terry B]

For photometry and astronomy, the bigger aperture is very important. Resolution is proportional to diameter of the scope so you will get more accurate astronomy. The big scope obviously collects much more light so you can measure much fainter objects for photometry or astronomy with the bigger scope compared to the little refractors.
As for the difference between the C11 or the RC10 I can't really comment as I have not used either scope.

[paulobao]

Thanks for the comments. I need to make a decision soon and untill that I will continue to search the web. I don't want to make a mistake here!

Regards,

paulo