TS-Optics 12" Ritchey-Chrétien Pro RC Telescope 304/2432 mm - Carbon tube

TS-Optics 12" 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.

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.

High back focus for correctors, reducers and also binoviewers.

High-quality 3" MONORAIL focuser

Astrophotography with the RC telescope:

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 M117x1 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.

You can connect the camera via 2" receptacle or thread it via the M77x0.75 female thread on the extension tube and M74x0.75 male thread of the focuser. Suitable adapters can be found in the accessories section.

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 500 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 3" 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 rail instead of small ball bearings for more stiffness.

No tilting anymore when locking the drawtube.

360° rotation for optimal object alignment

M77x0.75 female thread on the extension tube and M74x0.75 male 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 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.

Astrophotographic results obtained with this telescope on Astrobin

The RC telescopes are very well suited for astrophotography. Here you can find some astrophotographs made with this telescope model: Link to Astrobin

Adjusting the RC telescope

We recommend the TSRCKOLLI or an collimating telescope for adjusting the telescope. These tools are linked in the "Cleaning & Collimating" section.

Instruction video

Teleskop-Service has created an instruction video about collimating an RC telescope:

Astrophotographic results obtained with this telescope on Astrobin

The RC telescopes are very well suited for astrophotography. Here you can find some astrophotographs made with this telescope model: Link to Astrobin


M82 through the TS 12" RC
Patrick Otto

click on the image to see full resolution

44 x 4 minutes - with Canon EOS 1000DA at ISO 800
-- Reduction of the focal length with CCDT67

--

NGC891 made with TS 12" f/8 RC
Ivo Tschager


click on the image for a bigger size

Telescope: 12" f/8 TS RC Telescope
-- Camera: modified Canon EOS 500D
-- Exposure time: 48x12min
-- Astrophotographer: Ivo Tschager

A few beautiful images from Wolfgang Promper (www.astro-pics.com):

M94

Technical information:
LRGB 120 40 40 40
12" GSO RC with ASA Flattener
FLI MLx694 Camera




NGC 4490

Technical information:
LRGB 120 40 40 40
12" GSO RC with ASA Flattener
FLI MLx694 Camera




M 63

Technical information:
LRGB 100 40 40 40
12" GSO RC with ASA Flattener
FLI MLx694 Camera




M 13

Technical information:
RGB 40 40 40
12" GSO RC with ASA Flattener
FLI MLx694 Camera



Congratulations on the awesome photographs!