If I'm not mistaken the reason the moon eclipses the sun is because the ratio of distance to size, in regards to the moon and sun, is 1:1. And is it not also true that the reason we only ever see one side of thre moon is due to the fact that the moon is tidally locked to the earth? Now, given the above two are correct, would it then not be possible to have a configuration of moon, star, and exoplanet such that there would be a permanent eclipse on said planet?

• do you mean the Lagrange points? – Adrian Howard Aug 11 at 0:36
• @AdrianHoward Essentially yes lol – user235207 Aug 11 at 13:48