I'm looking for the title of a short story where astronomers find the exact position where the Star of Bethlehem (a supernova in that story) was and an expedition is sent to it. If I remember correctly, the fact that it was the star of Bethlehem is only revealed to the reader very late in the story (of course, the expedition knew it from the beginning, this is why they went there in the first place).
This was almost certainly turned into an episode of the 1980s Twilight Zone show.
From the Wikipedia entry:
This episode is based on a short story, "The Star" by Arthur C. Clarke, which was first published in Infinity Science Fiction (November, 1955). However, while Clarke's story ended with the priest in despair after the revelation that the alien civilization had perished in order to light "the Christmas star," the TV episode included the addition of an epitaph by the aliens, revealing their optimism about their place in the universe.
So the correct answer is this.