- Aperture 8" / 203 mm - focal length 1624 mm - focal ratio f/8
- Hyperbolic primary and secondary mirror for very high sharpness on the optical axis and a large well-corrected field for astrophotography
- Mirrors made of fused silica for stable focus position
- 94% dielectric high-reflectivy coating on main and secondary mirror for an even brighter image
- Carbon tube - more rigidity and better focus stability for astrophotography
- Quicker cooling down thanks to open construction
- Vixen style dovetail on one side and Losmandy style dovetail on the other side
- High-quality 2" dual speed MONORAIL focuser with 2" / 1.25" reduction adapter - motor focuser optionally available
- Spacer sleeves for optimal focus position behind the focuser are included.
- RC correctors for larger sensors from APS-C upwards are optionally available
- Optional: CCD47 - 0.67x focal length reduction for photography our recommendation for shorter exposure times
TS-Optics 8" f/8 RC Ritchey-Chrétien Telescope with Carbon Tube.
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.
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.
- 94% dielectric high-reflectivity coating on main and secondary mirror for an even brighter image.
- Significantly shorter cooling down time through open construction
- Internal baffles in the tube for even more contrast.
- High back focus for correctors, reducers and also binoviewers.
Astrophotography with the TS-Optics 8" RC telescope:
Better and sharper astrophotos without corrector with shorter exposure times. This is exactly what this RC telescope allows you to do with astro cameras and SLRs up to APS-C sensors. As a pure mirror system, you can even use the infrared light. You can achieve up to 25% shorter exposure times and sharper imaging than, for example, through a comparable Schmidt-Cassegrain telescope. For the use of a reflex camera without focal length reduction you need the 50mm and the 25mm extension between focuser and telescope.
The generous backfocus also allows the connection of correctors, which we recommend from the use of full-frame sensors. You can also connect a focal length reducer, thus further increasing the light intensity of the RC.
0.67x CCD reducer for astrophotography
The CCD47 improves the focal ratio from f/8 to f/5.36, thus reducing the exposure time to less than 50%. With this, you can capture dim nebulae and galaxies with moderate exposure times.
The advantages of a carbon tube over a metal tube:
The weight reduction is minimal - only about 300 grams - the main advantage ist the focus stability when temperature changes. That is important for astrophotography. When temperatures drop, metal contracts and the focus moves. Refocusing is necessary. A carbon tube does not change, the combination of quartz glass mirror and carbon composite tube makes a readjustment of the sharpness obsolete, even for long time exposures.
The 2" MONORAIL focuser - more than a Crayford:
The Monorail focuser combines the ease of movement of a Crayford focuser with the stiffness of a rack-and-pinion focuser. Thus astrophotography becomes a success.
- Massive stainless steel bar instead of small ball bearings for more stiffness.
- No tilting anymore when locking the drawtube.
- 360° rotation for optimal object alignment
- Female M69x1 thread for threaded adaptions
- 2" and 1.25" compression rings for push adaptions
- 1:10 dual speed for accurate focusing
- Motor focus can easily retrofitted
- Lined scale for quick retrieving of the focus.
- Easy operation
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 94% reflectivity.
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.
Technical Data:
- Optical Design: True RC with a hyperbolic primary and secondary mirror
- Aperture: 203 mm / 8"
- Focal length: 1624 mm
- Focal ratio: f/8
- Resolution: 0.58"
- Reflectivity: 94% reflectivity non-tarnishing dielectric mirror coatings
- Back focus: 254 mm from the tubeŽs backside or 159 mm from the 2" receptacle of the focuser
- Tube Diameter: 230 mm
- Tube Length: 580 mm with focuser
- Weight: 7.6 kg with focuser and dovetails
- Tube Material: Carbon composite with internal baffles
- Total Obstruction by Secondary: 85 mm
- Focuser: 2" dual speed MONORAIL
- Connection Thread: M90x1
- 2x Dovetail Bars: 2x GP style
In The Box:
- 8" f/8 RC Astrograph
- 2" dual speed MONORAIL focuser
- 2x Dovetail
- M90 extension tubes for easy reaching of the focus
- Collimation manual
For further selection of telescopes, cameras and accessories, please visit us in our online shop at teleskop-express and enter the product no. TSRC8C