What is an OTA?
OTA stands for Optical Tube Assembly and it refers to the tube of a telescope that contains the optical components like lenses or mirrors. In Astronomy the path the light takes is called the optical train. Both reflector and refractor telescopes have an OTA.
Key Takeaways
- OTA is the tube that contains the optics.
- Optical tube assembly can contain mirrors or lenses
- OTA can be solid or truss tube, and some large telescopes do not use an optical tube.
Understanding OTA
In astronomy the OTA is the Optical Tube Assembly. It is the main part of the telescope that collects and focuses the light to the eyepiece so that you can observe objects with a telescope.
Optical Tubes hold the components of a telescope in the correct positions to collect and focus the light to the focuser which is located at the back or side of the OTA.
All telescopes have some type of OTA, but they may look different.
Solid tube OTAs are solid tubes that you cannot see inside. Solid tubes are sturdier, but heavy. Larger telescopes, especially large reflector telescopes, use a truss tube, meaning that they are supported by a series of poles that hold the mirrors in the correct positions.
Some home made telescopes may even use a square OTA as they are easier to construct at home.
The purpose of the OTA is to hold the optical components in the correct position and to block out excess light. This can be accomplished without a physical tube.
Some telescopes, especially those built inside observatories may not use an optical tube, but may mount the optical components to the building in fixed positions.
Liquid telescopes do not use an optical tube, but rather build the telescopes inside an observatory.
