If I got it right from Das Boot and a few readings, WWII submarines had two periscopes. One, in the conning tower (the \'attack\' periscope?) and other in the control room (the \'observation\' periscope?). Is that right?.
If so, would you please forgive my ignorance and tell me:
-the differences between those two periscopes (optics, etc.)
-why was it deemed necessary to have two
-why one was placed in the comparative isolation of the conning tower.

Thank you very much

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