Thanks, Sue.
Glad to be of help, kiraalt.
It's been a while, here goes.
You are at the study. Exit to be at the corridor.
Across you is that room with gears and chop-chop.
To the left is continuation of the hallway to the astrologium and right is the exit out of here.
Go left in that corridor and you shoul be (I hope) at the room with a big clock - astrologium.
At right in that room should be the passage that you exited out from the room with the dead person.

Keep us posted.