An Altazimuth or alt-azimuth mount is a simple mount used for moving a telescope, camera, helostatic mirror, or solar panel along two perpendicular axes of motion, one vertical and one horizontal. The vertical movement is known as the altitude, while the horizontal motion is called the azimuth.
The biggest advantage of alt-azimuth mounts is their simplicity in both manufacture and use. They are often used for beginner telescopes, or for spotting scopes, but are still widely in use for more advanced instruments. In the latter case, advanced electronics and motors are sometimes attached to compensate for the restrictions of the mount's simplicity.
In astronomy, alt-azimuth mounts were, for a time, surpassed in popularity by the more complex equatorial mount. The latter is more naturally suited for tracking astronomical objects in the night sky as the Earth spins on its axis, since its polar alignment means that only one axis need be adjusted rather than the two of an alt-azimuth mount. Being able to track such objects reliably is particularly important for astrophotography, as well as more advanced amateur astronomy, both of which became more accessible when equatorial mounts became affordable.
In recent decades, alt-azimuth mounts have once again become very popular for astronomical telescopes: