The Galileo Observatory is notable in GTA V myths because it is the location of the All Seeing Eye, and served as a catalyst for other GTA V myths. However, I believe there may be a new connection.
The Galileo Observatory is inspired by the Los Santos Observatory from GTA San Andreas. This Observatory is located within the Verdant Bluffs, at the highest point of the eponymous bluff. This area is notable in GTA SA myths for being only one out of three locations where the notorious hiker pedestrian is found. This ped is known to be a fervent member of the Cult.
In fact, the Observatory is believed by many players to not even be one - some say it's a business front by the group, and others say it is a straight-up place of worship. Indeed, for a small public location, it receives a lot of religious pilgrims.
Now, this leads into my theory. The Galileo Observatory is the HD Universe equivalent to one of the most important locations in solving the Epsilon mystery. Because of the All Seeing Eye, there is already occult imagery in the area. What if this area serves as a congregation for Epsilonists or forwards their goals somehow, just like it's predecessor?