After collecting the correct three memories, grab a floppy disk that ejects from the Memory Transference Station.
With the floppy, head to the Planning Offices above Engineering and insert the floppy disk into a computer to the right of the box spawn, against the wall. This will unlock the door to the OPC.
Go up to the OPC and watch the anomaly open. It will fail to stay open, and you must return to Dr. Peck. Interact with him and he will eventually shutter the window.
Ravenov will then give you access to a locker to the left of Peck's window. Open this locker to acquire the Aethermeter from inside.