HUGE TELESCOPE TO STUDY MOON.

Star (Christchurch), Issue 17854, 24 May 1926, Page 4

HUGE TELESCOPE TO STUDY MOON.

, .MAKING THE WORLD S j.i. LARGEST REFLECTOR. * ' PARIS. April 5. A telescope morO than twice as large jus any in existence, by means of which _ it is hoped to observe stars 15.000 times more distant than any that are now Visible through the largest instruments, is being built in Paris by the American professor. George Willis Ritchey. Through it he estimates that the moon would appear only ten miles away and the observable universe would l>c increased 1.500.000 times in The new reflector is to be 19 feet 8 ffiches in diameter. It is almost ready for the critical baking process, upon which fts success is expected to depend. and should be finished during ,the summer. „• Professor Ritchey has been superintendent of instrument construction at the Verkes Observatory. U.S.A., vt. professor of astronomy at th 6 Uni—versity of of Chicago, and superintendent of instrument construction at the Solar Observatory of the Carnegie Institute. at Pasadena. California. In 1924 he was awarded the Jansen gold medal for designing and construct„c. ing a 100-inch reflecting telescope, then the largest in the world. It was believed by astronomers that .. the limit of size in telescope construction had been reached because of the , differences of expansion and contraction in the parts of a large solid reflector mirror. Tn the new parabolic mirror Prof. Ritchey believes he has , ..'.overcome this difficulty, by making the mirror in cells resembling those of a hov.evcomb. will permit circulation of air to all parts of the mirror, so that ex- “ pansion and contraction will be uni**_’form at all points. If this experiment is successful there will be no limit to the size of telescopes, except in the mechanical difficulties of handling them and the money necessary for their construction. Unable to get American manufacturers to undertake the construction of the instrument, he succeeded in inducc.vjing the Societe de St. Gobain to finance the effort. Special equipment was necessary., the furnace in which the reflector will be built being the product of more than • two years of scientific labour. The baking process will take more . than four weeks, and the astronomers will not know until the huge glass block has cooled whether the lens is a success.