Optical Tube Assemblies
Optical tube assemblies, commonly abbreviated by astronomers as OTAs are simply the tube of the telescope where the optics are internally located. OTAs can be helpful in a situation in which an observer has a compatible mount and doesn't want to buy a whole new telescope with a mount included. Optical Tube Assemblies can come in the form of Maksutov-Cassegrain, Astrographs, Reflectors, Refractors, Schmidt-Cassegrains and many others! With the right mounting connections and range of mount and tripod payload, OTAs are a great choice for changing optical type without changing the mount.