Wiktionary
n. (context astronomy English) A telescope that has an attachment which blocks out the direct light from the sun or other star, allowing examination of the corona and the detection of exoplanets
Wikipedia
A coronagraph is a telescopic attachment designed to block out the direct light from a star so that nearby objects – which otherwise would be hidden in the star's bright glare – can be resolved. Most coronagraphs are intended to view the corona of the Sun, but a new class of conceptually similar instruments (called stellar coronagraphs to distinguish them from solar coronagraphs) are being used to find extrasolar planets and circumstellar disks around nearby stars.
Usage examples of "coronagraph".
At the front was her small pressurized hab compartment, and there were two pallets at the rear fitted with a bunch of instruments that would be deployed at the neutron star: coronagraphs, spectroheliographs, spectrographic telescopes.
There was a scheme to observe major solar events like spots and flares from the two widely separate vantage points of Ares and Earth, and so there was a whole bunch of instruments which would be directed at the sun: a coronagraph, a spectroheliograph, a spectrographic telescope.