IN STARRY SKIES

Evening Post, Volume CIX, Issue 73, 27 March 1930, Page 23

IN STARRY SKIES

MOUNT WILSON

AN EXAMPLE FOR US

(By "Omega Ccntauri.") At noon upon the mountain's purple height, Above the pinewoods and the clouds it shone, Ko larger than the small white dome of shell Left by the fledgling wren when wings aro born. By night it joined the company of heaven, And, with its constant light, became a star. ■•- .. . High in heaven it shone, A.i.:i-'O with all the thoughts and hopes »nd dreams Of man's adventurous mind. Alfred Noyes. New observations, nowadays, are generally established on elevated sites. There is also a marked tendency for observatories near the sea level either to move to more favourable positions or to establish branches at higher levels., The * original observatory at Madras, for example, was 23ft ;ibove the sea, the present one at Kodaikanal \a at a height of 7745 ft. The first Mount Etna Observatory was at 155 ft. The now one is. at 9735 ft. The Lick Observatory, as we have seen, is 4209 ft; Lowell Observatory at Flagstaff, Arizona, is 7293 ft, and Mount Wilson is 5704 ft above the level of the sea. The latter is on one of the higher peaks of the Sierra Madre Bange. The site, so carefully chosen, has proved to be au ideal one. It is now easily access-

ible. The trail, originally about 2ft wide, has been transformed into a good motor road. Astronomers have no objection to its position between the desert and the deep sea, for the changes in temperature are moderate and the usual wind velocities aro low. Storms do not occur in winter, and some beautiful photographs show the mountain tops deeply draped in snow, but in summer the weather is mostly calm and the skies cloudless. Haze and fog are left | far below. The trees, which cover the mountain, protect the ground from the hoat of the sun, and so diminish the air currents, which would tend to spoil the "seeing." On an average 290 days a year aro suitable for good observation. The observatory was originally a solar one, the main purpose being a thorough study of the sun. But from the very first Professor Hale regarded the sun aa a star, the only one near enough to be examined in detail. Solar problems therefore were studied in their relation to stellar, evolution. The original plans provided for the establishment of the Snow horizontal telescope for solar work and the 60in reflector for stellar observations. But as wo saw last week, the growth of the observatory has been phenomenal. A GO-foot tower telescope, and a 150-foot tower telescope have been added for the intensive study of the sun, and a lOin photographic refractor and the lOlin Hooker reflector, with a 50-foot interferometer, for stellar and nebular study.

Tho photograph shows the 60in refractor, which was designed by Professor G. W. Bitchey, and constructed under his supervision. Its principal focal length is 300 inches, but it can be used also with focal lengths of 80, 100, and 150 feet. It has a plato carrier

with two guiding microscopes. The image can thus be kept constantly in true adjustment on the photographic plate during the long exposures necesjsary for faint objects. This splendid 'instrument was completed in 1908, ana for the next ten years was the largest telescope in active use. It was with it that Professor Eitchey took moat of- the magnificent photographs which have made the grandeur and beauty of celestial objects known throughout the world.

The Mount Wilson Observatory affords a stirring example for us in many ways. It shows what can be accomplished by well-directed efforts, inspired by enthusiasm. It would require many articles to recount its scientilic achievements during the last quarter of a century. We shall refer •to a few special points only. The photographic record of the sun's surface now available for future study contains over 50,000 plates. The nature, sizes, and distances of nebulae and star clusters have been revealed by photography. Spectographs hi«ve furnished a wealth of information about the constituent elements, the temperatures, motions, intrinsic brightness, and distances of the stars. The interferometer has enabled th diameters of stars to be measured, although they appear but as luminous points in the greatest telescopes. Heat radiations that have taken hundreds of years to come to us from distant stars have been measured by a delicate thermocouple. A modern observatory is not complete without a laboratory, and Mount Wilson possesses a most excellent one. It is not placed, however, upon the mountain, but down in Pasadena. In it solar and stellar phenomena have been imitated in a way which has greatly aided their interpretation. But it is not of this scientific work that we want •pccially to speak to-day. We have urged again aud again the importance of interesting the public in the widest and grandest of all the sciences. Mount Wilson is doing glorious work in this way. Most of the

photographs of celestial wonders that we have shown were taken there. The benefits thus conferred on all seekers after truth aro not confined to America by any means, but those who live in California or visit that country are more directly catered for. About twenty thousand people actually visit the observatory every year. In the afternoon they can see the buildings and the great Hooker telescope^ and can study the wonderful collection of celestial photographs. On Friday evenings they can gain free admission by ticket and may then see the moon, the planets, double stars, nebulae, and clusters through the (iOin reflector. Now it is opportunities such as these that wo hope to secure for New Zealand. We have quod and suitably elevated sites in Central Otago. 'Unfortunately we haveneither Carnegie nor the Carnegie Institution. We have, however, nearly a million and a half people. If they could bo inspired with the necessary vision, the rest would be easy, and wo should have the People's Observatory in two or three years. It is hoped that those who aro interested in this project will bring forward practical suggestions at tho meeting to be held at Silverstrcam to-morrow. The problem is to make a vivid conception of the greatness of the universe a normal possession of tho people. Life will inevitably bo ennobled by such an extension of the outlook. There is no danger of the mines of hidden treasures so revealed ever being worked out. The solution of one problem suggests a hundred more. The joy is in the search. We need never fear that in scientific studies we shall have to lament the absence of fresh worlds to conquer, and thcro can be no satiety in the exploration of the infinite universe.