TS-Optics 10" Ritchey-Chrétien Pro RC Telescope 254/200 mm - Carbon tubeRitchey Crétien telescope for high-level astrophotography with 3" Monorail focuser
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
Astrophotography with the RC telescope
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-reflectivy 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.
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
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 directly via 2" receptacle.
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 RC10´s three-inch mono rail focuser:
The 3" mono rail focuser is a further development of the crayford design. The load is not carried by four (often underdimensioned) ball bearings but on a stainless steel track on the base, thus preventing tilting and bending even under high loads. It is countered by a big knurled screw that centers the inner tube exactly to the rail. The load is distributed evenly across the rail´s surface.
Optical Design: True Ritchey Crétien / RC
- 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
- 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.
The Astrograph is a real Ritchey Crétien reflector telescope. Contrary
to Maksutovs or Schmidt Cassegrains which have spherical mirrors and need
image correctors, and contrary to Newtonians that need coma correctors,
the RC system is a well corrected photographical instrument hat uses
only mirrors (no false colour!) and does not require any corrector with
The RC has a concave hyperbolic primary mirror and a convex hyperbolic secondary mirror.
resulting image correction throughout the field as well as the
sharpness on the optical axis are superior to typical
Schmidt-Cassegrains or Newtonians.
It is for this reason that the
Ritchey Chrétien is very popular for astro imaging. The RC optical
system (and a variant of the RC) is the most frequently used design for
professional telescopes such as the 10 meter Keck telescope on Hawaii,
or the VLT in Chile. Finally the RC is also available for amateurs
without a "Nasa budget".99% Dielectric High Reflectivity Coating
primary mirror of the 10" RC is made of quartz which, similar to Zerodur, has practically zero thermal expansion for excellent optical properties during cool-down.
Both primary and secondary feature a 99% high reflectivity coating which
is well protected against scratches and against aging. Compared with
similar instruments you get a much higher effective light gathering
power.Fixed primary mirror cell and computer optimized baffle system
similar telescopes have a movable primary mirror cell. When focusing
the telescope the entire mirror is moved. Unfortunately this technique invariably leads to a certain amount of image shift. Most manufacturers
have controlled this problem to a fair extent, but the remaining image
shift can be quite distracting for astro imaging, particularly with
cameras with a small sensor size or when taking series of frames with
severyl hours of total exposure time.
In the TS RC the mirror
sits in a fixed mirror cell and focus is changed with a separate
focuser. This eliminates the problem of image shift completely.Collimation of the secondary mirrorand main mirror
primary mirror is fixed in its precisely machined mirror cell.
Collimation of the telescope is done through the secondary mirror.
Collimation is rather easy and can even be done by an inexperienced
amateur astronomer - we do however recommend to take your time with the
- 10" f/8 RC Astrograph
- 3" Crayford Focuser with 2" and 1 1/4" Adapter
- Losmandy style Dovetail Plate
- Primary mirror ventilation
- M117x1 Extension Tubes
Powerful 10" Ritchey Crétien with Quarz Optics and Carbon Fibre Tube.