Does a captain of a submarine look through a telescope or periscope?

Periscope, most modern subs ( WW-2 to date) have two, it is known now that submarines used by the Royal Italian Navy had an auxiliary zenith oriented periscopic theodolite/sextant that could be used to take fixes on celestial objects while at scope or siphon depth- also useful in tracking hostile aircraft- this aimed straight up, and was used mainly on Italian subs. Device was evolved by the Officine Gallileo or Gallileo Office- in Italian Officina is more like workshop or craft-assembly a small unit ( but high quality) shop- not a big mass-production factory. Of course on the surface sub officers and lookouts keep the watch with- Binoculars and these days some specialized night vision scopes...