Unrelated. In real life the observation scope was often called the "night scope" because it had better light gathering capabilities. The attack scope was about 3 inches in diameter at the top, the observation scope about 6 inches, so twice the size and could be seen by the enemy more easily in the daytime.
In the game the enemy destroyers don't see the periscopes or hear you on sonar, they put a quick call into the Psychic Friends Hotline and find you with mental telepathy.
