What are the six types of telescope?

Optical telescopes can be classified by three primary optical designs (refractor, reflector, or catadioptric), by sub-designs of these types, by how they are constructed, or by the task they perform. They all have their different advantages and disadvantages and they are used in different areas of professional and amateur astronomy.

1) Refracting type telescopes (Dioptrics)
Achromatic telescope
dialytic refractor
Apochromatic
Binoculars
Opera glasses
Copyscope
Galileoscope
Monocular
Non-achromatic
Galilean telescope
Keplerian Telescope
Aerial telescope
Superachromat
Varifocal gas-lens telescope

2)Reflecting type telescopes (Catoptrics)
Cassegrain telescope
Dall–Kirkham telescope
Nasmyth telescope
Ritchey–Chrétien telescope
Gregorian telescope
Herrig telescope
Herschelian telescope
Large liquid mirror telescope
Newtonian telescope
Dobsonian telescope
Pfund telescope
Schiefspiegler telescope
Stevick–Paul telescope
Toroidal reflector / Yolo telescope

3)Catadioptric type telescopes (Catadioptrics)
Argunov–Cassegrain telescope
Catadioptric dialytes
Klevtsov–Cassegrain telescope
Lurie–Houghton telescope
Maksutov telescope
Maksutov camera
Maksutov–Cassegrain telescope
Gregory (Spot) Maksutov-Cassegrain telescope
Rutten Maksutov-Cassegrain telescope
Sub-aperture corrector Maksutov-Cassegrain telescope
Maksutov Newtonian telescope
Modified Dall–Kirkham telescope
Schmidt camera
Baker-Nunn camera
Baker-Schmidt camera
Lensless Schmidt telescope
Mersenne-Schmidt camera
Schmidt–Cassegrain telescope
ACF Schmidt–Cassegrain telescope (Meade Instruments)
Schmidt–Newton telescope
Schmidt-Väisälä camera

4)Telescopes classified by the task performed
Astrograph
Astronomical optical interferometry
Comet seeker
GoTo telescopes
Graphic telescope
Infrared telescope
Meridian circle
Robotic telescope
Solar telescope
Space telescope
Spotting scope
Sun Gun Telescope
Zenith telescope