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Show TRYING A BIG TELESCOPE. Preliminary Test of the Forty Inch Lenses For the 1'erkes Observatory. In Cambridge on Sunday evening there was an experimental test of the great 40 inch telescope now being made for the University of Chicago by Professor Pro-fessor G. R Hale, the astronomer, under un-der whose directorship the new Yerkea observatory of the University of Chicago Chi-cago will enter upon its career; a friend of his, a rising young physicist last connected with the Massachusetts institute in-stitute of technology; Mr. Clark and his assistants. The great lenses, the largest that the world has ever seen, each of them equal in diameter very nearly to an ordinary buggy wheel, weighing with their mountings more than 1,200 pounds, were maintained in their position posi-tion high in air by a great steel tube, 63 feet in length, and seeming in the- aimness or tiie mgnt almost interminable. intermina-ble. The ponderous tube is poised midway mid-way upon a great shaft, which permits free motion in every direction, and this again is perched upon a massive pier of masonry capable o. upholding in safety the tons of weight which it is called upon to bear. Mounting the stcpladder which served serv-ed as a tompbrary observing chair, Professor Pro-fessor Hale placed his critical eye at the tube, and then in deliberate succession succes-sion applied the different tests known to astronomers. To the uneducated eye the glass on this preliminary test was truly at perfection, but the trained eyes of the experts caught points at times whereby the delicacy of the instrument might be increased. Then the planet Mars came within range of the instrument. instru-ment. The first view of this object by Professor Pro-fessor Hale brought forth exclamations of delight, for this telescope by far exceeded ex-ceeded in light collecting ability any instrument which he had previously turned upon the planet. Mars showed itself as a great reddish yellow disk, whose clean-cut edges attested the excellence ex-cellence of the instrument. Its brightness bright-ness with 40 inches of aperture was almost al-most sufficient to blind the eye, and its great disk was figured with the dark and light markings which define its to pography." For an hour or more the planet plan-et was kept in view, delighting every one of the assembled group with the splendor of the sight Then began a Bearch for the satellites. These are faint stars, visible at their best only with good apertures, and so close to the planet as to be hardly beyond the glare of light which it diffuses. The outer one, Deimos, was easily caught, but for some time Phobos, its companion, could not bo discerned. It was at last seen by Mr. Clark almost against the body of its principal, and for nearly half an hour it was followed by the different dif-ferent members of the company. The lenses, excellent as they have proved to be, will again be placed in the shop, and with the knowledge gained gain-ed of their minor inaccuracies of figure they will again undergo local treatment until they reach that high standard which has placed the Clark glasses always al-ways in the van in point of interesting astronomical discovery. Boston Transcript. |