The coronagraph mask refers to the disk or devise in the telescope that actually block out the light from the star. There are several types of advanced coronagraph masks incorporating the latest advances in optics and digital technology.

First is the band-limited coronagraph mask. This is a development on the basic coronagraph mask. Where basic coronagraphs utilize an opaque disk to block the light of the star, the band-limited coronagraph mask is designed not only to obstruct the light from the star but also to manage the other effects of the light blocked. It must be noted that light acts both as a wave and a particle, this means that blocked light particle “bounce” off the blocking material. The band-limited coronagraph mask manages the “bouncing” of the blocked light among other things. This form of coronagraph mask has been planned to be incorporated in a satellite telescope designed to look for planets outside our solar system.

Another kind of coronagraph mask is the phase-mask coronagraph. This coronagraph mask does not rely on an opaque object to block the light from the star but rather uses a transparent mask that acts as a filter designed to block only the light emitted by the star. This mask is significantly more advanced and theoretically would allow more area around the star to be seen. A noted limitation of opaque masks is that they actually block a significant portion around the star. It must be noted that even the smallest area around the star translates to literally thousands if not millions of kilometers of space.