TS-Optics 8 inch f/8 Ritchey-Chrétien Astrograph Telescope with EQ5 Mount

TS-Optics 8" f/8 RC Ritchey-Chrétien Telescope on Skywatcher Mount EQ5

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 equatorial mount EQ5 from Skywatcher:

The equatorial mount EQ5 handles the RC telescope with very good stability, sufficient for visual observing and astrophotography. The mount comes with a rigid tripod made of stainless steel that can be extended up to 1400 mm.

The mount is upgradable from polar finder over motor drives up to a complete GoTo system with autoguiding interface. Thus the EQ5 becomes an ideal base for astrophotography.

...More information about the Skywatcher EQ5 mount

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

Hyperbolic primary and secondary mirror for a large fully corrected 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

Internal baffles in the tube for even more contrast.

High back focus for correctors, reducers and also binoviewers.

High-quality 2" MONORAIL focuser with 2" and 1.25" receptacle.

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.

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.

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

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 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 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.

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.

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

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