What is the proper alignment for the disks in the Colossus?

Hint 1 of 4:

It's in plain sight.

Hint 2 of 4:

In fact, look just outside the Colossus.

Hint 3 of 4:

There is a drawing on the wall of the lava room that shows you the proper
positions.

Hint 4 of 4:

Note that the symbols for full/new moon and noon/midnight look a lot
alike.  One symbol in each pair has a nick below it, so you can tell the
two apart.