THE PROPOSED SOLAR OBSERVA. TORY.

Dominion, Volume 6, Issue 1746, 10 May 1913, Page 3

THE PROPOSED SOLAR OBSERVA. TORY.

_____ I Sir,—One cannot read the announcement „ of Mr. Thomas Ci.vthron's munificent 0 offer of tcu thousand pounds towards tho 0 establishment of a solar physics obscrva- „ tory in Nelson without admiration, and f a great sense of gratitudo that scitntific efforts and accomplishment should be 60 j appreciated. It is a spirit worthy of . imitation by other wealthy colonists, and J I take up my pen to write what I feel it is incumbent on me to say, with a senso / that I may be accused of an ingratitude, that I am very far indeed from possessing. * But I consider it to bo the duty of J scientific men to stato fearlessly and with- I out hesitation their opinion oil scientific * matters, so that liberality such as this ; mar bo directed into channels where it will be of the greatest possible use to the f world in general. For science is univer- c sal, recognising neither country nor lan- s gunge, and those scientific institutions, of c which only,a few are required (like solar J physics observatories), should be placed 1 whoro they will bo most effective, other- F wise tire money is misspent, and Science J may be charged vith establishing ' luxuries when necessities are unsupplied. s I do not mean that a solar physics ol>- J sorvatory in the Southern Hemisphere is i a luxury. It is not. It is, in the right t placo, a necessity. Ono more such ob- 0 sorvatory will probably fill all the needs of the world in this respect for very many years to come, if it is put where it will bo most effective. Ten such observatories in ; wrong places will not do as much good; and to be in the best possible place, there is no doubt whatever that any new solar physics observatory shoild be—(l) In the , tropics; (2) at a high altitude; (3) south , of the Equator; and (4) somewhere about " the longitude of New Zealand or Aus- 9 tralia. It should be south of the Equa-, ' tor because the two principal solar ob- * servatories in the world are north of it. 1 These are Mount Wilson, in Arizona, and ® Kodai Canal, in India. When it is win- ' ter at these places, and the sun in con- j sequence not so high above the horizon as ' it is in. the northern summer, it is summer J south of the Equator, and the sun is best ( situated for. observation. It should be in 1 about our longitude, is the object of such ( institutions is to study tils sun, and at 1 midday here, when the sun is at its great- c est altitude, it is at these other places t either low down or. the horizon or has t actually set. It is' a sine qua non that < it should be as near the tropics and at s as high an altitudJo a 9 it can bo for the c reason that the object being to study the t sun, and to study the sun effectively, the e locality should be so chc/Sen that the sun 1 reachos as great a midday altitude as \ possible. Witliin the tropics it is vertical i overhead twice eaoh year; outside theso r : limits it is never vertical; and the fur- c ther we recede from them the lower it ] sinks towards the northern horizon at i midday. In all astronomical work this j atnosphere of oars—necessary as perhaps , it may be for some other things—is a ] nuisance, and tho object in locating an , observatory for tte special purpose of ob- J serving the sun is to get rid of as much , as possible of it- The observatory shonld, j therefore, be placed so as not to increase ( the thickness of (he atmosphere by look- . in? obliquely through it, and as high up as possible, so as to get above the dense, dusty, moistura-laien atmosphere near tho , 'surface, into the clear, cold, and cloudless regions above. For similar reasons it i should not be near the sea, or the very, mountains upon which it Should be placed will causa a condensation of moisture ■ and prevent its usefulness by surrounding it with cloud. These are the ideals, and it is not al- ; ways possible to make them the reals; and of course Mount Wilson may be quoted at ; once as an example of a solar physics observatory,; which is not in Uie tropics. It 1 is in lat. 84 deg. north, but it is at an altitude of 5900 feet, well above the clouds as one of Miss Proctor's beautiful lantern slides, and also the same picture used as an illustration in Lowell's "Evolution of .Worlds" shows. The exceptionally clear atmosphere there compensates for the undoubted disadvantage of ,beingi Udeg. north of the tropics. Tho other chief solar physics observatory, and practically the only other one of importance in the world, is «t Kodai Canal in India, 7700 feet" high and lldeg. north of the Equator and l'2deg. inside the northern tropical line. Now consider any part of New Zealand for this kind of thing? The extreme north of it is in Lat. S4deg. south, and the climate there—well, I don't want to hurt North Island people's feelings. It is not till yon come to Nelson that you get at all a clear, sky. This is in latitude 41 S. The sun, tho object you want to study, even at midday in midsummer, does not come within 18 degrees of the zenith, and at midday in midwinter it is GTdegrees from that pint. At Kodai Canal the sun (it midday evon in midwinter is never more than 34 degrees from the zenith, that is, 30 degrees higher. If we go into the hills near Nelson one might get up about 3000 feet, hut instead of. rising above the clouds you get into thesvand the climate of the surrounding hills is not so good nor so clear as the climate of Nelson itself. If a solar physics observatory is to be established in New Zealand, to a great extent regardless of whether it is of much real use to the world or not, then I believe thattho climate of Nelson is such that it will do more good there than in most other places in New Zealand, but in my opinion it will leave things just where they b.t'6 in the matter of real discovery, and in no sense supply the demand for .one where it can aid these other two and do real good valuable work. And I think that genuine scientific work is what Mr. Cawtnron has in his mind and not tho mere establishment of an observatory. There are, however, two branches of physical science that New Zealand is especially fitted for. We in the scientific world do really want a geophysical observatory here, where terrestrial magnetism. atmospheric electricity, earthquakes, and a host of other problems which this earth of ours presents differently here in New Zealand from what it does in other parts of the world can be studied. To some extent we have this in the little Magnetic Observatory in Christchurch, but to meet the demands of scienco the scope of this place wants greatly enlarging, and the' work carrying on in vigorous whole-hearted style. It might be that a place near Nelson could b'e found where this institution could be carried on in a very much enlarged way, although tho magnetic conditions are rather bad. The other thing that I .have in my mind is one which unfortunately could not be placed in Nelson,. In 'Central I Otago there is an almost rainless region at an altitude of- over 4000 feet. It is,! too, in I>at. 46 S., and stars of 46 southern declination pass overhead, and tho South Pole of the Heavens is 46 degrees above the horizon. If a well-equipped Stellar observatory wcro placed here there is no doubt whatever that the work it would accomplish would be of the utmost value to astronomy. The observatories at Cape Town, Perth, Adelaide, Melbourne, and Sydney are all north of Lat. 34, and they are all just about sealevel, and some of them in pretty smoky atmospheres at that. In my opinion, there is not a single place in the whole world. where a Stellar observatory could be established with greater advantage than in Central Otago. It really ought to ,be done. If Mr. Cawthron wants to assist astronomy, as I am sure he does, he cannot possibly do it a greater service than by assisting in the direction I have ' named. lam sure the claims of a i Stellar observatory in New Zealand are now far in excess of those of, a solnr one, and if Central Otago be the sito they aro overwhelminglv so.—l am, etc.. C. COLERIDGE FAKE. Physical Laboratory, Canterbury College.