OTA Telescopes - Optical Tube Assemblies
If you already own a mount and want to expand your equipment with a new telescope, an optical tube assembly - OTA - is the natural choice. OTA telescopes are sold as standalone tubes without a tripod or mount, giving you complete freedom to pair them with the setup you already have or to build a new combination tailored precisely to your observing style and budget. Whether you are upgrading from a beginner instrument, adding a second tube to your existing mount, or assembling a dedicated astrophotography rig from scratch, an OTA telescope gives you full control over every component of your setup.
Types of OTA Telescopes
Our range covers all the main optical designs used in amateur astronomy, each with its own strengths and ideal use cases.
Refractors use a lens objective to gather and focus light. They are prized for their sharp, high-contrast images and are particularly well suited for planetary observation, the Moon, and double stars. Refractors require virtually no maintenance and are ready to use quickly after being taken outdoors. Shorter focal ratio models (f/5 to f/6) also perform excellently for wide-field deep-sky observation and astrophotography.
Reflectors - most commonly in the Newtonian design - offer a large aperture at a lower price compared to refractors of the same diameter. A bigger aperture means more light-gathering power and the ability to resolve fainter deep-sky objects such as distant galaxies, nebulae, and faint star clusters. Newtonian OTAs are a popular choice for visual deep-sky observers and astrophotographers using equatorial mounts.
Catadioptric systems combine lenses and mirrors in a compact body. The two most common designs are the Maksutov-Cassegrain and the Schmidt-Cassegrain. Both offer long focal lengths folded into a short and portable tube - making them ideal for planetary observation, the Moon, and for observers who need a high-performance instrument that travels easily. Schmidt-Cassegrain OTAs are also widely used in astrophotography thanks to their flexibility and the wide range of available accessories.
Which OTA Design Is Right for You?
If you enjoy observing planets, the Moon, and double stars, a refractor or Maksutov-Cassegrain will reward you with sharp, high-contrast views. If your main interest is the deep sky - galaxies, nebulae, and star clusters - a Newtonian reflector with a larger aperture will show you more. For those who want one versatile instrument that handles both, a Schmidt-Cassegrain OTA is a popular all-round solution.
Why Buy an OTA Without a Mount?
Purchasing an optical tube separately from a mount has several clear advantages. First and most practically, if you already own a compatible mount, you can reuse it and invest your budget directly into better optics. Second, you gain the freedom to choose the exact mount that matches your observing or imaging needs - a lightweight alt-azimuth for casual visual use, or a precise equatorial GoTo mount for astrophotography. Third, OTA telescopes are the preferred choice for astronomers who build and upgrade their setups gradually - starting with one tube and mount, and expanding with additional tubes, cameras, or accessories over time.
Many experienced amateur astronomers own several OTA tubes that they interchange on the same mount depending on the observing session - a wide-field refractor for star clusters and nebulae one night, and a long focal length Maksutov for planetary detail the next.
Compatibility and Mounting
Most OTA telescopes in our range are fitted with a Vixen-compatible dovetail bar or tube rings with a standard dovetail, making them compatible with the vast majority of equatorial and alt-azimuth mounts available on the market. Some larger tubes use the wider Losmandy D-plate standard. Always check the weight capacity of your mount against the weight of the tube you are considering - a well-balanced setup is essential for comfortable visual use and especially for astrophotography.
Find the Right OTA for Your Setup
Whether you are looking for a lightweight and portable tube for travel and quick sessions under the stars, a large aperture reflector for deep-sky exploration from a dark site, or a compact catadioptric for high-magnification planetary work, you will find the right optical tube in our range. Browse by optical design, aperture, focal length, or intended use - and take your astronomy to the next level with a telescope that fits exactly what you need.
