Newton OTA (Optical Tube Assembly)

Due to a loose Newtonian reflector OTA (OTA stands for Optical Tube Assembly—in other words, a bare tube!) By combining it with a mount of your choice, you can assemble a telescope with a massive aperture at a surprisingly affordable price. These separate reflector telescope tubes are available in a variety of sizes and focal lengths, making them perfect for both visual observers and avid photographers. Our fastest models, also known as Imaging Newtonians called, are the ultimate wide-field powerhouses. Combine them with a stable equatorial mount, plug in your DSLR or dedicated astro camera, and you're ready to shoot razor-sharp deep-sky images!

Not sure which telescope suits you? We are stargazers ourselves and happy to help.

Send us a WhatsApp message

We reply on weekdays between 9:00 and 17:00.

Showing 1–20 of 35 resultsSorted by popularity

Showing 1–20 of 35 resultsSorted by popularity

Newtonian OTA: tube only, you choose the mount

A Newtonian OTA (Optical Tube Assembly) is the bare telescope tube with mirrors, focuser, and tube rings, without a mount and tripod. You buy it if you already have a mount, if you are looking for a specific photographic Newtonian, or if you want to put a larger tube on your existing equatorial mount. This category includes the Sky-Watcher Explorer PDS and Quattro, the Omegon Pro astrophotography scopes, and the ProNewtons.

Visual or photographic?

  • Explorer-P (visual). Standard focuser, brand, designed for visual use. Inexpensive and reliable. Explorer-150P OTA and Explorer-200P OTA.
  • Explorer-PDS (visual and photo). Dual-speed 2-inch focuser and a primary mirror positioned slightly further forward, so a camera can reach focus. The standard photographic Newtonians in this price range: 130PDS, 150PDS, 200PDS, 250PDS.
  • Four (photo, f/4). Very fast, short exposure times, but a coma corrector is mandatory and collimation is critical. Quattro-150P and Quattro-200P.
  • Omegon Pro Astrograph (photo, carbon). Carbon fiber tube that does not expand with temperature changes, keeping the focus set all night long. 114/456 up to 254/1016.

Which mount goes with it?

Rule of thumb for astrophotography: the payload capacity of the mount is at least twice the weight of the OTA plus camera. A 130PDS (around 4 kg) works on an EQM-35 or EQ5. A 150PDS (around 5.5 kg) on an EQ5 or HEQ5. A 200PDS (around 9 kg) on an HEQ5 or EQ6-R. A 250PDS on an EQ6-R or heavier. The mounts are listed at accessories.

What you need for it

A laser collimator, a coma corrector for f/5 and faster, and for astrophotography a dew heater strip for the secondary mirror. Complete sets with mount can be found at GoTo reflectors. Note: Sky-Watcher and Omegon.