Michael:

Speaking of periscopes.......

The USS ADDER (SS-3) was the first U.S. Navy submarine to carry a periscope, in this case a British-made "Altiscope" in 1903. It was a "fixed direction" devvice rigged through the forward ventilator.

Much progress has been made in the periscope field. The LOS ANGELES (SSN-688)-class and SEAWOLF(SSN-21)-class attack submarines use the Kollmorgen Type 18 hull-penetrating scope. It includes multiple magnification levels, singleaxis stabilization, digital photography, low-light image intensification, color television, and day-and-night viewing capabilities.

The Navy's new USS VIRGINIA (SSN-774)-class submarine will be getting a completely new set of "eyes." The AN/BVS-1 Photonics Mast has replaced the traditional optical lenses and prisms of the conventional periscopes with electronic imaging equipment.
Each VIRGINIA-class submarine will have two photonic masts that
do not require physical penetration of the ship's hull, but instead "telescope" out of the sail.

Its fiber optic system carries images from the photonics masts to two work stations and a commander's control console, each equipped with two flat-panel displays and a keyboard, trackball, and joystick. The masts are quipped with three cameras - color, high-resolution black-and-white. and infrared - in addition to a
mission-critical control camera in a separate, pressue-proof and
shock-hardened housing and a laser range finder that will provide accurate ranges to targets and aids to navigation. All of these
sensors are housed in the mast's rotating head.

Regards,

ROBERT M.