Abstract
IN Occasional Notes Roy. Astro. Soc. (No. 4, March 1939), Dr. H. Knox-Shaw gives a very full description of the work on the erection of the 74-inch reflector at Pretoria, and three plates illustrate various parts of the equipment, the turret, the telescope itself as viewed from the north-east, and also the Newtonian observing carriage and the Coudé room. It is satisfactory to know that the pyrex disk for the large mirror has been successfully cast and the figuring will be completed in a few months, after which the mirror will be sent to Pasadena for aluminizing. It will be possible to use the telescope at three foci, Newtonian, Cassegrain and Coudé, the focal length in the first case being 30 feet, and the equivalent focal lengths in the last two being 111 ft. and 173 ft. respectively. The Newtonian focus will be used for direct photography and the other two for spectroscopic observation. A two-prism spectrograph for use at the Cassegrain focus is under construction and will soon be ready, and a projection measuring machine and also a microphotometer have been made for the Observatory. It is anticipated that the full programme of the work will be undertaken early in 1940, and the initial programme will include the determination of the radial velocities of the O and B type stars in the portion of the galaxy beyond the reach of the northern observatories. The object of this research is to corroborate present views on galactic rotation. When opportunities occur, photography of the nebulæ south of –40° declination will be undertaken.
Article PDF
Rights and permissions
About this article
Cite this article
The New Radcliffe Observatory. Nature 144, 19 (1939). https://doi.org/10.1038/144019b0
Issue Date:
DOI: https://doi.org/10.1038/144019b0