I have not seen any astronomical events in a long time and I desperately need the starcharts! My observatories are NOT off, either! Is this fixable? Has anyone experienced something similar?
A late-game science upgrade, SETI, makes astronomical events automatically observed. Since a bunch of spam about something you no longer need to worry about could get annoying, the developer also chose to have the SETI upgrade make astronomical events silent, meaning they no longer write to the log.
Your starchart continues to increase, and will do so faster the more observatories you have. There are also some space upgrades that can give starcharts over time.