I think the star maps are nothing more than showing where previous flood infestations have been discovered. I don't think there's a clue in them. The clues to opening server 2 had nothing to do with server 1. I think the servers tell the story, and the arg plays out in other ways.
In the transcript of the server 2 video it says
This may kill the theory that the flood is a science experiment gone wrong, but that's not 100%. We don't know who's sending these messages, but if it is from the Forerunners, concerning the first firing of the Halo Array, then it means they existed, and killed, before the Halo's were built.it spoke to us
{//} Mockingly, dismissively
It has done this before
{//} Elsewhere
Anyway, the Infestation image of got me thinking. It looks like a 3 step thermal analysis of a planet and possibly moon/sun throughout a Flood invasion. This means that whoever is sending these messages has studied the flood before, and is sending their information on to us, so that we might be more successful in stopping the flood without wiping out all galactic life.
So what if the star images are actually INCREDIBLY broad in scope, and we're not looking at a galaxy, but a larger chunk of the universe. The glyphs could indicate the area of invasion. The rotation of it is simply set to match a particular moon or planet of origin, and the infection reigns hell throughout the glyphs area. The second glyph, the second invasion. The final glyph... Earth perhaps?
Anyway, thats just me spitballing, wanting to contribute since so much has been done.