occulting bar

occulting bar

[ə′kəlt·iŋ ‚bär]
(astronomy)
A bar placed in the focal plane of a telescope eyepiece to cover part of the field of view, usually to cover a bright object in order to permit observation of a nearby faint object.
References in periodicals archive ?
It is best to try and keep the star just out of the field of view, or use an occulting bar.