ASTRONOMICAL NOTES.

Press, Volume LXI, Issue 18552, 30 November 1925, Page 4

ASTRONOMICAL NOTES.

FOR DECEMBER, 1925. | (srECIALLI WRITTEN JOB "XHS P»B3S.") I (By E. G. Hogg, M.A., F.R.A.S.) The sun will enter the zodiacal sign Capricornus on December 22nd, which will be the longest day in the. South-em Hemisphere, the duration of daylight being 15 hours 20 minutes. On that date the meridian altitude of the sun for the latitude of C'hristchurch will be about 69deg 56min. The planet Mercury sets on December Ist at 5.52 p.m., well to the south of west; its apparent magnitude on that date is 0.5. It is in inferior conjunction with the sun on December 12th at 3.30 a.m.. when its distance from the earth will be about 63,000,000 miles. Towards the close of the month it will be a bright object in the southeastern sky. Venus sets on December Ist at 10.54 p.m., and ou December 15th at 10.43 p.m.; its apparent magnitude changes during the month from —4.1 to —4.4. Mars rises on December Ist at 3.2 a.m., and on December loth at 2.31 a.m.; Jupiter sets qn these dates at. 10.27 p.m. and f>.42 p.m., respectively, and (Saturn rises on these dates at 3.30 a.m. and 2.40 a.m., respectively.. There will be an occupation of the planet Venus by the moon on December 19th, these bodies being in a line with the earth at 1.39 p.m.; the phenomenon will be visible as a close graze in the latitude of C'hristchurch.

The Royal' Observatory, Greenwich. One of the most interesting events of the current year has been the celebration, on July 23rd and 24th last, of the 250 th anniversary of the foundation of the Royal Observatory, Greenwich. The memories of few of the monarchs who have occupied the British Throne are held in less respect than that of Charles 11., but there stands to his credit the fact that he established the Greenwich Observatory, and started it on its great career of usefulness. The' story goes that in 16-74 u Frenchman, Lc Sicur do S. Pierre, came over to London to promulgate a scheme for determining longitudes at sea, a matter then, as now, of the gravest importance; he brought with him introductions to distinguished people, and his mission attracted much attention. His proposals came under the notice of the Rev. John Flamsteed, one of the most capable astronomers of his day, who pointed out that the Frenchman 's projects were quite inapplicable in the present state of astronomical science, inasmuch as the places of the stars were not known with the degree of accuracy which would be necessary if his methods were to be adopted. Flamsteed then goes on to say: "I heard no more of the Frenchman after thig, but was told that my letters had been shown King Charles. He was startled at the assertion of the fixed stars' places being false in the catalogue,, and said, with some vehemence, he must have them anow observed, examined, and corrected, for the use of his seamen."

No time appears to have been lost by the King in carrying his ideas in effect, as on March 4th, 1G74, he issued a warrant appointing "our trusty and wcll-bcloved John Flamsteed, Master of Arts, our astronomical observator, forthwith to apply himseif with the mOBt exact care and diligence to the rectifying the tables of the motions of tho heavens and tho places of the fixed stars so as to find out theso-much-de-pired longitudes of places for the perfecting the art of navigation," at the yearly salary or allowance of £IOO. A larger salary "appears to have been designed at first for the office, which was being created, but as Flamsteed was resolved on taking Holy Orders, a smaller salary was in his case deemed sufficient.

The next question to be settled was tho site of the Observatory, Hyde P4rk and Chelsea College we're both menturned as suitable localities, but, at Sir Christopher Wren's suggestion, Greenwich Hill was finally resolved upon. The King made a grant of £500; he also gave bricks from Tilbury Fort, while materials, in the shape of wood, iron, and lead, were available from a gatehouse demolished in the Tower. The foundation stone was laid on August 10th, 1675, and the building, designed by Wren, was completed in the following year. Here until his death, in 1710, Flamsteed carried on his work: no provision, however, had been made f6r instruments, and Flamsteed had to get these at his own expense; he had no assistant, and consequently all the 6b- . servations and their reduction he had Ito do himself. His "Historia Ceelestis Britaniiiese," published in .1725, contained the positions of some 3000 stars, ascertained with a degree of accuracy far in advance of anything hitherto accomplished. Halley* who is best known for his prediction of the return of the comet which bears his name, followed Flamsteed; like his predeecsso;-. ho found, the Observatory without instruments, as Flamsteed's executors had claimed those he had used. In 1721 he procured a grant of £SOO from the Board of Ordnance, and .'installed a small transit 'instrument, and in 1725 he procured an eight-foot iron mural quadrant made by Graham, and with these instruments he carried out a large number of observations, particularly of the moon. His lunar tables, from this work, were adopted almost universally by astronomers, those of the French nation being the only exception.

On Ilalley's death, in 1742, Bradlev became Astronomer-Royal. A grant of £IOOO from George 11, enabled, him to procure instruments of a high decree of efficiency, and with these Bradlcy may be said to have Said tho foundations of "modern astronomy of position; his skill, in the design and uso of his instruments rendered his observations far more precise than those of any of his predecessors. Our present knowledge of the direction of the sun's motion in space and of the existence of the two star streams in which the majority of stellar bodies near the sun participate is largely dependent on proper-motions derived by comparing later observed positions of stars with those found bv Bradlev.

Like Halley and Bradlev, the next Astronomer-Royal. Bliss, was an Oxford man: he held the position for onlv two years, and his fame is not widespread, but it may be mentioned that his College, Pembroke, treasures ar, etching of him, drawn by a. boon companion on the base of a pint-pot. and I surrounded by the inscription: "This sure is Bliss, if Bliss on earth there be.'' In 1764 Maskelyne came to Greenwich, and during the 44 years of his tenure of office he was assiduous in the observation of the sun, moon, planets, and a small number of the brighter stars, being specially interested in the problem of determining the position at sea, for which tho Observatory had been founded. Pond succeeded Maskelyne in 1811, and great improvement a were made in the instrumental equipment of the Observatory during his stay there. Pond's observations were of a very high order of accuracy, and his catalogue of 1112 stars was "a most valuable contribution to the precise determination of stellar positions. According to Admiral Smyth, he was buried in <h<! flame tomb as Halley. Airy, who followed Pond, held office from 1835 to 1881. Besides producing

mathematical work of the highest order, he greatly extended the scope and usefulness of the Observatory. He introduced improved methods of reduction of observations and had them published regularly and promptly; he adopted the use of registration by chronograph, an idea originating in the United States; ho also started the system of telegraphic transmission of time daily from the Observatory io the General Tost Office for distribution over Great Britain: magnetic and meteorological observations were introduced at Greenwich by him. and he also began the practice of daily photographing the sun and measuring the size and position of sun-spots. His,great work at Greenwich, was well summed up when, in 187"). he received the Freedom of the City of Loudon "as a recognition of his indefatigable labours in astronomy and of his eminent services in the advancement of practical science, whereby he has so materially benefited the cause of commerce and civilisation."

" When Airy retired at the age of 80, Christie was appointed: he held offico until 1910, when the present AstronomerTioyal. Sir Frank Dyson, was appointed. It is not proposed to sum up the activities of the Greenwich Observatory during the last forty years; to do so adequately would require more space than i«n be spared, but it may be said that, though questions of purely astronomical interest receive more attention there now than formerly, the original intentions of the founders of the Observatory are' being carried out consistently, and the practical applications of astronomical science, such as observations of position of the planets and stars, the distribution of time, the care of the Navy chronometers, and the compilation of sun-spot and magnetic charts, still form the main work of the institution.

Sydney Observatory. It will be unwelcome news to all interested in astronomy to learn that the Sydney Observatory is to be closed; the State Premier (Mr Lang) holds, wo are told, that the Meteorological Bureau is all that the State needs to keep up. He believes that, tho Federal Government will take over the Observatory, and though one hopes tha.t such will be the case, it must be remembered that the Federal authorities have already decided to found and maintain a solar observatory in the vicinity of Canberra, and this they may regard a-s enough for the present. The Sydney Observatory was founded in 1858 on .the urgent representations of the then Governor of New South Wales, Sir William Denison, and in it were installed many of the instruments acquired by the Government of the Colony when the Parramatta Observatory was closed, in .1847. For some time the activities of the .new Observatory were limited to the daily, time-ball service, but gradually tho scope of its work was enlarged, and, under the able direction of th*e late Mr H. C. Eussell, F.K.S., the Government Astronomer, it came to be regarded as a first-class observatory. In April, 1887, at a concourse of astronomers representatives of nineteen different countries, held at Paris, it was decided to compile a photographic chiirt of the heavens on a scale never previously attempted, and the zone of the sky lying between declinations 52deg and 54deg south was allotted to Sydney. The heavy nature of the work to be done, and the great expense involved, may bo seen when it is stated that 1400 photographs of tho stars in tho zone would have to be taken, the plates would have to be measured, the measures reduced to scale, and the final results published. By 1009 the plates had all been taken, and 750 had been measured, but none had been reduced and nothing published; since that time it would appear that little progress has been made, for at the recent meeting of the International Astronomical Union a resolution was adopted urging the Government of New South Wales to expedite the publication of the Sydney portion of the chart. This may have brought matters to a head, for one. learns that the closure of the Observatory is in no small measure due to financial reasons. It is, however, to be hoped that the representations which are being made to the Government will induce it to change its policy, and' provide the Observatory with the money and the' staff it needs to fulfil the obligations it undertook nearly forty years ago.