TS-Optics 12" f/4 ONTC Carbon Tube Newtonian telescope - fully customizable

ONTC Newtonian Telescopes from Teleskop Service are a unique system on the market

You choose the components and the bias of your telescope and get a Newtonian without compromises for reaching your astronomical goals. Just tell us what you want to do with the telescope and we make it according to your needs.

The ONTC Newtonian with 303 mm aperture and 1200 mm focal length:
Astrophotographers will appreciate the Newtonian for the high speed of f/4. With suited correctors, the speed can be increased to f/2.8.

We suggest a bigger mount if you have interest in Astrophotography. The Celestron CGEM-DX, Skywatcher AZ-EQ6 or Losmandy G-11 should be the minimum. A good choose is the EQ8, if you want to mount the Newtonian in an observatory.

The advantages of the ONTC telescopes in short:

optimized configuration for astrophotographic or visual use by choosing different focusers, focus positions or secondary mirror

Exchange of the secondary without problems - anytime

Only selected optics are used. Also the functionality of the optical and mechanical components are tested before sending out the ONTC.

Each ONTC Newtonian telescope comes with a complete manufacturing protocol including star test.

The edge of the secondary is blackened against reflexes and false light.

The carbon tube is made in Germany. It is manufactured in a carbon/rigid foam sandwich construction for a perfect stability at an unbeatable weight ratio

Fantastic temperature compensating performance - barely any temperature based focus drift

The mirror cells are manufactured in Germany, too. The telescope can be collimated completely without tools.

One telescope, many focal distances - due to different correctors! The correctors need different focus positions above the focuser. The tube offers three positions of the primary mirror cell.

TS "Black" anti-reflective paint for maximum contrast

Many of our UNC and all ONTC Newtonian telescopes use the TS-Optics "Black" anti-reflective paint. It darkens the inside of the tube just as well as velour foil. The illustration shows how dark the anti-reflective paint is. The diagram (at the images at the top of this page) shows the direct comparison between the commonly used chalkboard paint and the anti-reflective paint.

Choose a suitable focuser in the "options" list

The free choice of the focuser makes the ONTC Newtonians unique. Thus you can easily adapt your new telescope optimally to your wishes. Please do not forget to select the base for attaching the focuser to the tube. You can choose from our whole range. A few recommendations are given below:

UNCN2-G2 - TS 2" UNC Newtonian Crayford focuser - short

Economically priced 2" Crayford focuser for observing and photography with DSLR cameras. The short focuser needs only 75 mm optical path.

Item number of the necessary base: BAST-UNCN2G2 - please add to your order.



FTF2008BCR - Starlight Feather Touch 2" focuser - 20 mm draw tube travel

The best 2" focuser we know, for maximal stability without compromises. In addition, the focuser is very short, together with the base, it is only 50 mm heigh.

Item number of the necessary base: BA20CL-356mm - please add to your order.



Orion ACU-3S 3" Crayfordfocuser with M82x1 thread

The massive 3" focuser is our recommendation for astrophotographers who want to work with a 3" Newtonian corrector (N-AGK3, TS 3" Wynne or TeleVue VIP-3010.) These correctors are screwed to the M82 thread of the focuser.

Item number of the necessary base: NB355-ORACU3 - please add to your order.



Starlight FTF3215B-A TRUE 3" Feather Touch Focuser

THE high-end focuser for Newtonian telescopes and real 3" Correctors from TeleVue, ASA or TS Optics. with very precise 3" compression ring clamping - as good as screwed adaptions.

Item number of the necessary base: BA32CL-358 - please add to your order.

We recommend three focus positions above the 2" tube of the focuser:

1. astrophotography with the standard coma correctors - 65 mm above the 2" tube (STANDARD Version)
This version is optimized for the standard correctors like the TS coma corrector, the GPU corrector, the Baader MPCC or the ASA Quattro. For visual use, you need to add the 2" extension tube - Art.Nr. TSV235.

2. astrophotographic use with the ASA 2" Reducer/corrector - 90 mm above the 2" tube
This position is ideal for the use of the ASA Reducer/corrector ASA2KORRR. The reducer brings the system up from f/4 to f/2.8.

3. Visual use - 35 mm above 2" tube
We recommend that version for visual use of the telescope. For this telescope line, we recommend the 58 mm secondary mirror. The 2" Paracorr VIP-2010 also works fine with this focus position.

The focus positions are calculated and achieved by changing the primary mirrors position. Of course you can also get other positions if you want. For expample if you want to use a 3" coma corrector. The three we mentioned are the most common ones.

Further customizable parts of the ONTC Newtonian telescopes:

If you order the instrument via our webshop, you can send us a notice in the text field below the payment methods. There is a textfield "Informations concerning your order" where you can tell us what you want to have. The alternative is dropping us an email : info@teleskop-service.de

Rings or bar directly connected to the tube - no change of the price:

The scope of delivery also includes rings with a flat base on both sides. According to your wish, we can also attach a dovetail bar (Losmandy or Vixen style) directly to the tube. If choosing that modification, the tube gets additional fibre layers where necessary.

Assembly and collimation instructions

The telescope is delivered disassembled into several units for safety. The assembly and adjustment are not complicated, you can download the instructions in advance. The PDF can be found here.

Astrophotographic results obtained with this telescope on Astrobin

Here you can find some astrophotographs made with this telescope model: Link to Astrobin

General product video

Teleskop-Service has made an information video about the UNC and ONTC telescopes:

Astrophotographic results obtained with this telescope on Astrobin

Here you can find some astrophotographs made with this telescope model: Link to Astrobin

Safety informations: PDF Download