TS-Optics ONTC 200 mm f/4 Carbon Photo Newtonian, fused quartz mirror and 2 inch RAP focuser

ONTC 8"-f/4 Newtonian telescope with 2" RAP focuser

This Newtonian has been developed from the proven ONTC telescope series. Here, too, only the best mechanics and selected optics are used. The result is a well thought-out telescope for astrophotography, but also for observation. At just under 8 kg, the Newtonian is a lightweight and is still carried by transportable mounts such as the AVX from Celestron or the H-EQ5 from Skywatcher. Nevertheless, the Newtonian offers very high stability thanks to the sturdy primary mirror cell and secondary mirror mount. The telescope can even withstand rough transportation without losing collimation.

Assembled and tested for you:

ONTC telescopes are assembled and tested for you in our company in Parsdorf. Only selected and previously approved optics are used. We attach great importance not only to the primary mirror, but also to the secondary mirror. Each ONTC is finely adjusted after assembly and tested on our optical bench before the telescope is prepared for shipping. Of course, a checklist is included.

Carbon fiber tube - made in Germany

Our carbon fiber tubes are made in Germany. The tubes have a robust wall thickness and are inherently rigid. Larger tubes have a layered construction, which increases rigidity and saves weight. The tubes are blackened on the inside with the blackest black (TS Black) we could find on the market. On the outside, the tubes are coated with a transparent protective varnish, which brings out the beautiful structure of the carbon fiber, and also protects it.

Very good internal blackening with TS-Black for maximum contrast

Our ONTC Newtonian telescopes use the TS-Optics "Black" anti-reflective paint. The inside of the tube is darkened just as well as with the velour film. The illustration on the left shows the difference between the familiar school blackboard paint and the TS anti-reflective paint.

Solid tube clamps from CNC machining

The tube clamps connect the telescope to the mount and also allow the installation of accessories such as a camera holder or a guide scope for astrophotography. The clamps are made of aluminum and are CNC-machined. They have internal threads for dovetail bars on the top and bottom. The inside of the clamps is lined with velour to prevent the tube from being scratched.

Main mirror made of fused quartz

The substrate material of the primary mirror is fused quartz. The thermal properties are similar to the well-known Zerodur. The special feature is that the mirror does not change its curve during the cooling phase. The image is optimal right from the start. However, other effects such as warmer air in the tube must of course be taken into account. The main advantage of the fused quartz mirror is with long exposure times and falling temperatures. Refocusing will hardly be necessary. The focus is held more stable than with a Pyrex or BK7 mirror.

One telescope - several focal lengths for photography

Long gone are the days when there was only one coma corrector for photography. Nowadays, correctors offer a focal length extension or reduction. Reducers in particular often require a larger backfocus above the focuser. ONTC Newtons offer three freely selectable focus positions, allowing you to use different correctors on one telescope and influence the focal length accordingly. Even if you later buy a corrector with a change in focal length, your ONTC will always provide you with a good basis.

These three focus positions above the 2" receptacle have proven to be very useful when working with a 2" corrector. The ONTC is already equipped with these positions.

35 mm (ideal for visual observation and for the TSGPU and the 2" PARACORR)

65 mm (standard setting for most coma correctors, such as TS Maxfield, Baader MPCC ...)

90 mm (for correctors with focal reducer, like TS2Korrr)

Assembly and collimation instructions

For safety reasons, the telescope is delivered disassembled into several assemblies. The assembly and adjustment are not complicated, you can download the instructions in advance. Link: unc_ontc_zusammenbau_kolli_en.pdf