KH 15D
KH 15D is a binary star in the Cone Nebula and it goes through very strange and long eclipses.
This can be explained if there's a dust torus around it and it goes through a precession (its rotation axis changes).
It's just above V427 Monocerotis (at 11:30 am from it).
Apparently, scientists found how KH 15D behaved between 1913 and 1950 as well as between 1967 and 1982.
Raoul