The Ritchey-Chretien (RC) represents the ultimate in amateur and professional telescope equipment - just ask any professional astronomer. RCs provide very wide coma-free fields of view, ideal for deep-sky imaging. Astrosib from Novosibirsk, Russia has a long history of making quality optics and for this they have a worldwide reputation. We are proud to exclusively offer these elite telescopes in the UK.
A few points about Ritchey-Chretien (RC) optics, as this sector of the market can be complicated:-
RCs cannot be made cheaply. They are expensive because the only way to make the two hyperbolic surfaces properly is to hand finish the surfaces. This requires a very high level of skill and experience. The process cannot be automated and maintain the accuracy needed.
Collimation is crucial with this optical design, requiring the tube design and construction to be adequate. Astrosib telescopes stay in collimation. Period.
Cheap RC telescopes will have mass-produced optics sourced far away from the ‘manufacturer's' quality control. If in doubt, wait for the reviews to come out before purchasing.
Alternative optical designs in this sector include derivatives of the Dall-Kirkham design, which use simpler primary mirror figures and employ a corrector lens system in front of the focal point. This lens system can then also act as a field flattener which the system also requires.
RC systems such as the Astrosib may require use of a field flattener when used with very large imaging chips. This can be a reducer/flattener such as the Astrophysics 0.67x unit which the also increases the actual field of view.
If you are going to use a webcam or Deep Sky Imager type device with a relatively small imaging chip, then the advantages of a true RC design will not be exploited. If you are going to use a large imaging chip, then the argument is as follows:- given that you are going to spend a significant 4-figure sum on a CCD camera, a significant 4-figure sum on an equatorial mount, and probably significant sums on the installation, filters, filter wheels etc - why cut corners on the optical system?
Renowned astrophotographer Nik Szymanek reviewed the Astrosib RC250 in the August 2008 edition of Astronomy Now magazine.
His comments include:-
"......the best lunar pictures (I've) ever taken"...." a pleasure to use".... " good correction and extremely low levels of coma"...... "excellent star images and very nice contrast"....... "Definitely recommended"
Supplied as a tube assembly, we can recommend and supply any and all ancillary equipment including equatorial mountings, focusers, filter wheels, optical accessories, digital imaging equipment, and enclosure for your home observatory. Please contact Simon for a detailed discussion of your requirements.
