TS-Optics 8 inch f/8 Ritchey-Chrétien Astrograph - Carbon on HEQ5 Goto Mount

TS Ritchey-Chrétien (RC) telescopes are known for their excellent optical performance, especially for photographical applications. But RC telecopes are also well known for their expensive price. Teleskop Service want to change this situation and with the help of GSO we offer a full line of true RC telescopes for the amateur to an affordable price.

Features of the TS RC Telescopes:

True RC Optic with a hyperbolic primary and a hyperbolic secondary mirror

Primary and secondary mirror are made of low thermal expansion quartz

The secondary mirror has a center mark for better and more simple collimation

99% reflectivity non-tarnishing dielectric mirror coatings

Big well corrected flat field without need of a seperate corrector

Enough backfocus for correctors and reducer

Less dew problems against Schmidt-Cassegrain or similar

Fast cooling down time because it is an open system

Each RC is tested and checked on our optical bench

How to find the focus with DSLR camera:

The TS RC has a generous back focus allowing to attach many accessories like e.g. off-axis guiders, filter wheels etc. If you want to take photos with a (D)SLR camera with the focuser in a moderate position, you need the following accessories:

GSRCV50: 50mm spacer, to be placed between focuser and telescope

TSFA240: T2 adapter with 40mm extension

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.

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.

Using an SLR without focal reducer: you need a 50 mm and a 25 mm extension tube between focuser and telescope (item # GSRCV50 and GSRCV25).

Using an SLR with focal reducer CCDT67 or CCD47: in this case, a 50 mm extension tube between focuer and telescope (item # GSRCV50) is sufficient.

Low Thermal Expansion Quartz Glass primary and secondary mirrors with 99% reflectivity:
Designed for astro imaging, TS RC mirrors are made of low thermal expansion quartz glass, rather than the ordinary optical glass used by competitors. Ground and polished under precision computer control to diffraction-limited or better surface accuracy. Both primary and secondary mirrors have a full 99% reflectivity for the brightest possible images. This is substantially higher than the 88% reflectivity of competitors’ conventional aluminum coatings or the 94-96% reflectivity of enhanced aluminum coatings.

The optical advantages of TS RC "Ritchey-Chrétien" Astrographs for astrophotography:
The TS Astrograph is a real Ritchey-Chrétien 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 that uses only mirrors (no false colour!) and does not require any corrector with many cameras.

Why the RC Telescope is better than Schmidt-Cassegrain telescopes with correctors:
This is also the advantage of RC telescopes against Celestron EHC or Meade ACF telescopes. These telescopes needs a lens corrector wich is integrated in the optical system. The RC is a true reflection system without lens corrector and with a really bright image.

TS RC Telescopes – the optical system:
The RC has a concave hyperbolical primary mirror and a convex hyperbolical secondary mirror. The resulting image correction throughout the field as well as the sharpness on the optical axis are superior to typical Schmidt-Cassegrains or Newtonians. Both mirrors are ground and polished under pricision computer control to diffraction-limited or better surface accuracy.
Fixed primary mirror – no shifting:
Most 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 several 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.

Ritchey-Chrétien Telescopes from Teleskop-Service – why they are so cheap comparing to similar RC telescopes:
Ritchey-Chrétien (RC) telescopes are known for their excellent optical performance, especially for photographical applications. At the same time however RCs were always notorious for being very expensive. To change this Teleskop-Service and "Astro-Tech" asked GSO (Guan Sheng Optics) to produce true RC telescopes. GSO is best known for their excellent Newtonian optics which they have built for many years now. The result of this joint venture is an instrument that is superior in most aspects to a conventional Schmidt-Cassegrain, and still comes at a very affordable price. Teleskop-Service is European distributor for these instruments from GSO.

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:

Astrophotos through the TS 8" RC:

M92 - Reinhard I.
In the section (remark: "Recommended Accessories"), besides the flattener, two 0.67 x reducers are also offered. I would like to point out to you that your TS Photoline Reducer 0.79 x (TSRed279) also gives excellent results with the 8" RC format, giving an interesting compromise between detail and speed with a focal length of about 1300 mm.

M27 - C. Frere

Cameras: Atik383L+ for H-Alpha and O-III

Farbe/Color: QHY8L

M20 - Hamish Thava

L-RGB

Camera: Starlight SXVR-H694

Filter: Baader L-RGB

Mount: Skywatcher EQ6 Synscan

NGC891 - Wolfi Ransburg

Camera: ATIK 4000 Mono

no corrector

12x 12min

Andy Murner

Moon (valley in the moon alps)

DMK Camera from Imaging Source