THE EQUATORIAL MOUNTING OF THE GREAT LICK TELESCOPE. From a Photograph by Mr. E. E. Barnard. 



The central ptirt of the tube of the great telescope is shown at the top of the picture, with its attachment to the declination axis, a steel shaft at 

 right angles to the polar axis, which latter lies within the iron casing at the top of the pillar. The polar axis always points to the pole of the hpavens. but 

 can turn upon itself, carrying the T piece, or casing of the declin ition axis, with it. Tlie telescope can turn about the declination axis so as to be pointed 

 to all parts of the heavens. The divided circle at the left hand of the picture is the declination circle, which gives the angular distance from the equator 

 of the heavens of the point to which the telescope is directed. The divide I eirrli> aSout the pjlui- aKi^ Ljivos tlir po-itinn of th- tnlr=c ipe in right ascension. 



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