Altitude/Azimuth telescope mount

More about the Altitude/Azimuth mount.
(Looks very much like a naval turret gun.) The "Alt-AZ" mounting has some important advantages over the equatorial mounting. Most (all) large modern telescopes use the alt-az system.

• It's one of the lightest systems.
• Takes up less room.
• Simple
• Cheap

  But, no "free lunch" - The disadvantages are:

• Requires three motors to synthesize equatorial motion!
• Requires much more sophisticated control.
• Even though it can point at zenith; It can not track near zenith!
  Note the animation of the LAT tracking Arcturus. When Arcturus is near the horizon the altitude part of the mount is moving "fast". When Arcturus is closes to zenith, the azimuth part of the mount is moving fastest. If a star is very close to the zenith, the azimuth would have to spin nearly 180 degrees in a very short time.

All in all, for all the seemingly short-comings. The alt-az is a practical price/performance solution. Solution to the Alt-az to equatorial motion are well known. Computers (needed for image processing, telescope control and tasking) are now relatively inexpensive.