Show CANADA HAS BIG TELESCOPE reflecting apparatus at victoria if Is said to be the largest yet constructed A seventy three inch reflecting telescope which ranks in sue sile as the largest telescope of that type yet cow plated has been constructed for the dominion astronomical observatory at victoria canada the instrument ie Is described in I 1 copular mechanics the mirror which in this aspe ot of telescope tel scope takes the place of a EL lena lens in concentrate concen trat ing the rass of light men measures 79 inches in diameter over all Is 12 inches thick at the edges and Is pierced by a R hole ten and one eighth inches in dl ill ameter the upper surface Is s a parabola to bring the reflected light to a focus rocus SO 30 feet above the mirror this enormous enor mons piece of glass weigh weighs tw ta 0 and one quarter tons and yet Is so accurately supported that no flexure can distort the murfa surface ce which must nowhere noNN here deviate from the theoretical curve more than a 1000 of an inch the instrument weighs 55 tons and will rest on massive piers of reen re en forced concrete the tube is 31 feet long ind in d NN weighs 12 tons of 0 unusual interest from an engineering point of view are the dome and observing bridge the former is 30 33 feet in n di dl ameter ani Is provided with a double shutter ha hai ing an opening 15 feet wide all the movements including revola tion to any desired position as well as the he operation of the shutter wind shield ani an I 1 the observing bridge are accomplished by means of electric motors |