Astrophysics (index)

Occulting Bar

(telescope feature to block light from a specific body)

An Occulting Bar is a bar-shaped attachment for a telescope designed to block light from a bright object in view so that other objects can be seen more clearly. Like a Coronagraph, it is a type of Occulter, the terms essentially suggesting their shape: a rectangular bar shape versus a circular shape such as would be used to block out the Sun. The reason for the bar shape is convenience in mounting with adequate performance for many types of observations. Occulting bars are used with large research telescopes and are easily devised for small amateur telescopes, typically for observation of objects near the line of sight to a bright star.