Photo Gallery: EL/AZ (ALT/AZ) Mounts

In the field of astronomy, the angle to an astronomical object above the horizon is called altitude; instead of elevation. Consequently, an EL/AZ mount is often called an ALT/AZ or altazimuth mount.

Some astronomical telescopes can be moved in altitude only; azimuth is fixed. These telescopes are called meridian telescopes.

In the fields of film and video production, the terms pan and tilt are commonly used to describe the motion of a camera: pan describes left-right motion and tilt describes up/down motion. The mounting mechanism is commonly called a head; Thus, a camera is said to be mounted on a pan-tilt head.

By any combination of terms, the basic idea is the same: it's a device (head, mount) that moves another device (antenna, camera, telescope, whatever), in two directions, up/down and left/right.

Following are illustrations of EL/AZ mounts used in several fields:

• Satellite Antenna on Fixed EL/AZ Mount: 3-meter AFC antenna. The azimuth and elevation angles are fixed when the antenna is installed, and locked into position.  If the antenna must be moved to a different satellite, both axes must be adjusted manually. Azimuth is adjusted by rotating the entire antenna about the circular track at the base; elevation is adjusted by changing the length of the elevation struts.



• Satellite Antenna on Steerable EL/AZ Mount: Vertex 6.1-meter antenna on motor-driven EL/AZ mount. Axis labels.   If the antenna must be moved to a different satellite, both axes must be adjusted. Both axes are adjusted by changing the length of the motorized actuators; this adjustment can be made from a remote location.



• Remotely-controlled Pan/Tilt Head supporting video camera: Model QPT-90 Pan Tilt Head, QuickSet International Inc., North Brook, Illinois, USA. This pan/tilt head supports a "towercam" video camera used by a television broadcast station to televise live video of the surrounding landscape.
  


• Remotely-controlled Pan/Tilt Head supporting radio antenna: Pelco, Clovis, California, USA. This pan/tilt head supports an Electronic Newsgathering (ENG) microwave antenna used by a television broadcast station to receive video from remote news and sports venues.
  


• Manually-controlled Pan/Tilt Head for photographic or video camera: Velbon model VE-3C.
  


• Small Optical Telescope on ALT/AZ Mount: 3.5-inch Orion telescope on wood mount fabricated by the owner. Note that azimuth axis is always vertical.
  


• Large Optical Telescope on ALT/AZ Mount: W.M. Keck Observatory, Hawaii. The twin Keck Telescopes, the world's largest optical and and infrared telescopes.
  


• Large Radio Astronomy Antenna on ALT/AZ Mount: Scatter Radar Antenna, Millstone Hill Observatory, Massachusetts Institute of Technology, Westford, Massachusetts. Note the circular track on the ground, which allows the entire structure to rotate about the azimuth axis.  Axis labels.
  


• Manually-steerable Shipborne Radar Antenna on EL/AZ mount: General Electric Mark 26 Fire Control Radar Antenna formerly used by U.S. Navy. Now on exhibit at the Historical Electronics Museum, Linthicum, Maryland.   Axis labels.
  
  
• Fixed microwave antenna: 24-inch fixed microwave antenna on EL/AZ bracket.