SECOND LARGEST TELESCOPE

Wanganui Chronicle, Volume 80, Issue 251, 22 October 1937, Page 12

SECOND LARGEST TELESCOPE

TO LEAVE NEWCASTLE SHORTLY FOR SOUTH AFRICA. The world’s second largest telescope —the result of two years’ Tyneside craftsmanship—will leave Newcastle within the next few months for the new Radcliffe Observatory in Pretoria, South Africa. Costing about £40,000, the telescope has been constructed at Walkergate-on-Tyne, and it has a “great” mirror, 74 inches in diameter, weighing two tons. Months of work are involved in the production of this mirror. ( Made of Pyrex glass it is ground spherical and then polished in the shape of a parabola. Smaller mirrors used in the giant telescope are made of fused quartz. Accuracy on the construction of the telescope with its mirrors and movements requires to be to one millionth of an inch. The instrument will be housed in a steel turret, 61 feet in diameter, and the tube, made of duraluminium, is 35 feet long. Although the moving parts alone weigh some 35 tons, the whole apparatus can be worked by the touch of push buttons. Eighteen motors are used in operating the telescope, and the other equipment, in addition to spectroscopic arrangements, includes a special camera which has two guiding microscopes.