Stellaris is located in RB 6 201
at
NYU Langone Health, 540 First Avenue, New York, NY  10016

There is also a back way in by walking through Tisch Hospital on the 3rd, 4th, and 5th floors.

If you have ID swipe access, next to the elevators there is a door with a swipe. Enter here and make a right turn. RB 2-601 is at the end of the hall to the left.