Most large professional telescope are constructed according to the RC principle. Until recently, these telescopes were unaffordable for amateurs. RC telescopes from Teleskop Service are primarily aimed to amateur astronomers with photographic interest. These telescopes are perfectly suited for high-resolution astrophotography. Of course, an RC can also be used for visual observing. Here, the large corrected field of view is noticeable, too. In total, the stars are sharper than, for example, in a Schmidt-Cassegrain.

Due to the large corrected field of view, you can, for example, use a DSLR up to APS-C format without corrector. Thus the RC is a pure mirror system for astrophotography. The images become ultrasharp. For imaging dirctly in the focus, you will need the M90x1 extension tubes which are supplied. They are threaded between telescope and focuser, thus reducing back-focus.

The generous back-focus also allows attaching correctors which we recommend when using sensors of at least full-frame size. You can also attach a focal reducer, thus further increasing the speed of the RC.

We recommend especially two focusers fitting directly to the M90 thread of the tube. MonorailM90 - the reasonably priced standard focuser. We recommend the focuser for visual observation and for lighter photo equipment, like e.g. DSLR cameras. The focuser already provides all the prerequisites, such as micro-reduction and support superior to simple Crayford focusers. We recommend the focuser for accessories up to approx. 3kg

Main mirror & secondary mirror: Quartz glass does not change its dimensions if temperature changes. When the temperature changes slowly during an exposure, other mirror substrates, like Pyrex, tend to a deformation of the mirror and thus to a shift of the focus. This problem does not exist for mirrors of quartz glass. Thus the focus is better maintained which is very important for long exposures. Both mirrors are coated with 99% reflectivity. The image is obviously brighter than the one of telescopes with only 90% or 94% reflection layer.

The TS RC astrographs are true Ritchey-Chrétien telescopes. Maksutovs and Schmidt-Cassegrains have spherical mirrors and need correctors for making a large field usable. With Schmidt-Cassegrains, you can see the aberrations in the field even when working visually. Most times, Maksutov-Cassegrains are so slow that they are not suitable for astrophotography. RC telescopes have hyperbolical primary and secondary mirrors. They are more difficult to manufacture, but offer a significantly sharper field with less aberrations throughout the field.

Telescopes with focusing via movable primary mirror often suffer from the "shifting problem". The image shifts while focusing or even jumps. By now, Meade and Celestron have the problem under control, but the effect is noticable nonetheless. TS RC telescopes do not have this problem, as their primary mirror is fixed. Focusing is done via a high-quality focuser. An additional advantage is the optimal distance from primary to secondary mirror. This gives you the guarantee of the best possible image. If the primary mirror moves relatively to the secondary, you will practically never have the optimal distance.

Characteristics:

• Hyperbolic primary and secondary mirror for a large fully illuminated field of view
• Astrophotography with camera sensors up to 30mm diameter possible without corrector. For larger sensors, like full-frame size
• 94% dielectric high-reflectivity coating on main and secondary mirror for an even brighter image
• Significantly shorter cooling down time through open construction and active primary mirror ventilation
• Internal baffles in the tube for even more contrast
• Long back focus for correctors, reducers and also binoviewers

Delivery:

• 8" f/8 RC astrograph OTA
• Carbon tube with optimized baffle system
• 90mm extension tubs
• 2" Monorail focuser w/ gear
• 2x dovetails - 1x Losmandy / 1x GP style