I've discovered, as have a lot of other people probably, that by hitting CTRL-N to respawn a map, ascencion crystals aren't removed after the new game is created.
I was doing this a number of times, and then decided to play the game as it was with the numerous ascencion crystals. I would say there were and average of about 3 on each sector, although it may have been less.
I came across a star that when I clicked on it, rather than giving me the usual information it showed as if there were two invisible ships on that tile. When I moused over the two invisible items, it showed one to be the star's name (I believe it was something like Denton or Demter), and the other item was "ascension crystal".
When I clicked on the invisible icon for the star, the screen went dark, and then crashed to desktop.
I don't know if it's normally possible for ascension crystals and stars to spawn on the same tile. But in the event that it does happen, it can crash the game.