Photonics mast
A photonics mast (or optronics mast) is a sensor on a submarine which functions similarly to a periscope without requiring a periscope tube, thus freeing design space during construction and limiting risks of water leakage in the event of damage. A photonics mast replaces the mechanical, line-of-sight viewing system with digital equipment, similar to a digital camera array, and it has fewer locational and dimensional constraints than a traditional periscope.