TS-Optics GSO 6" f/9 RC Ritchey-Chrétien Telescope

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.

How to reach focus on the 6" RC

Reaching focus is not a problem on the RC. Without extension sleeves, the back focus from the 2" connection is about 159mm. But included are three M90 extension sleeves (1x 50mm 2x 25mm) which are simply screwed between the focuser and the tube. This allows you to focus any accessory, starting from 1.25" and 2" zenith mirrors but also various correctors and all common cameras.

The advantages of the TS-Optics RC Telescopes at a glance:

• Hyperbolic primary and secondary mirror for a large fully illuminated field of view.
• Astrophotography with camera sensors up to 30 mm diameter possible without corrector. For larger sensors, like full-frame size, Teleskop-Service offers ready-to-use corrector solutions.
• 99% 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.
• High back focus for correctors, reducers and also binoviewers.
• High-quality 2" Crayford focuser for 2" and 1.25" accessories with compression ring
• Due to a redesign of the baffle tube, problems with stray light no longer occur. Nevertheless, the illumination is still very good. Sensors up to full frame format can be used.

Primary and secondary mirror of quartz glass with 99% reflectivity and protective dielectrical quarz layer:

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 advantages of TS RC telescopes for astrophotography:

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.

Why is the RC Telescope superior to Schmidt-Cassegrain telescopes with correctors:

Celestron EHD or Meade ACF telescopes need a corrector. Additionally, these telescopes have a Schmidt plate at the front side which is prone to dew. The RC is a pure reflection system without lenses in the light path. Thus you can use the complete light even in the infrared range. The image is brighter and the exposure times get shorter. The field of an RC telescope is coma-free by design and relatively flat.

No shifting problem with TS RC telescopes:

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.

Features:

• Optical Design: True RC with a hyperbolic primary and secondary mirror.
• Aperture: 6" / 154 mm
• Focal Length: 1370 mm
• Focal Ratio: f/9
• Resolution: 0.76"
• Reflectivity: 99% reflectivity non-tarnishing dielectric mirror coatings
• Back Focus: 159 mm from 2" connection of the focuser
• Tube Diameter: 191 mm
• Tube Length:500 mm with focuser
• Tube Weight: 5.4 kg
• Obstruction by secondary: 77 mm
• Focuser: 2" dual speed Crayford focuser
• Connecting Thread: M90x1
• Dovetail Bar: 1x GP style