ASTRONOMICAL NOTES FOR JUNE.

Lyttelton Times, Volume CXVI, Issue 16870, 31 May 1915, Page 4

ASTRONOMICAL NOTES FOR JUNE.

j The sun reaches its farthest, north j ii;,t one minute before miduight between Juno 22 and 2H. so that both these days must bo considered equal and the shortest of the present year. The position of the sun is then in right ascension ti hours, and declination 23deg 27min north, which is not far from the star Eta Geminorum. A smaller star of the fourth magnitude, 1 Geminomin, according to Flamsteed’s system of enumerating the stars, is actually behind the sun when at the solstice. On June 2-5 the moon will occult the urat magnitude star Antarcs in the Scorpion, and hide it for more than an hour. The following times were really calculated for the latitude and longitude of Wellington Observatory, but will bo correct within, two or three minutes for any other place in Now Zea- ! land:—Disappearance of star 10.4 a p.in., reappearance 0.1 a.m. on June L'li. Antarcs is such a bright star that there is no difficulty in seeing him near the moon, and certainly a pair of fieldgla.sses will he sufficient to make the observation easy. .. . , There are no planets visible in tne early evening at present. Saturn is actually in conjunction with the sun on Juno 29. Jupiter is conspicuous in the morning sky, but at the beginning of June does not rise until nearly 1 a.ni. He is seen about 3i minutes earlier each successive day, and rises at 11.13 p.in. on June 30. Venus is still the “ morning star,” rising between 4 and o a.ro. throughout the month, i The most interesting object for amateur observers during June is Melhsh’s comet. The moon has rather obscured jit lately: still it has been an easy naked ■ eyo object for two or three weeks, so j there is no doubt it will he easily folI lowed throughout tho month. Its near- ■ est approach to the earth occurs on 1 June 6. when its distance from us is ! thirty-six millions of miles. The prei dieted place for June 3 «:— R ight asI pension 21hr 14mm. declination bdde.g 1 Smin south. After that date only rough ephemeralhave been comI puted. partly because o bright comet is ! easilv found with or without lnstrilI incuts, but chiefly because the predicI tions of its places cannot ho made exact ! Owing to its proximity to the earth, it will suffer certain perturbations affecting its motion, and while it is really so ! close to u« these displacements will look rather large against the background of tho sky. The position quoted above s from an ephemeris published by Ale bmirne Observatory, and it shows tin comet to be in the constellation Indm The u-eneral trend of its mo-ion frou. there is across the circumpolar heavens through the constellations Toucan, H,.drus. Reticulum and Dorado, until t reaches Pictor on June 30. This n taken from an approximate ephemeris calculated at the Dick Observatory frou elements giving the date ofpenhel.o. passage as July 17. An earlier predictjnn published in Europe and receaeo hv a recent Engl eh mad accepts Jul y~, as perihelion date, and mokes the met ‘pass further south, traversing ho constellation Octans, m which the outh pole is actually situated. At tho mooting oftheßojalAsdro iomica 1 Society on March 12, tho farrt Paper read was a contribution from Dr Eothoringham on what is called ths calar acceleration of the moon r : m rion The rate at which the muon moves round the earth is■ “"BtaiitJ -rowing more rapid, and the task ot those who study the lunar theorj w to determine the increase of speed h> discussing observations distributed ove a long period of time. Dr bothering bam w an authority on chronology ns v.,-11 as mathematics, and the interest in his paper lay chiefly in his discussion of some occulta tions ot stars b> the moon recorded by 1 toleiny in tho Almagest written in the second century.” This is the first time that early occultations have been used for this purpose, hut eclipses of the sun recorded in ancient history have been examined by several mathematicians, including Dr Fotheringham himself in investigating the moon’s motions. There are a number of such eclipses mentioned by different writers, but usually the difficult!’ is to decide from the narratives whether the total phase itself was actually seen at the place mentioned, and very often the locality itself is not quite certain. One of these, which may he mentioned bore a.s an example, is called tho eclipse of The record in in Xenophon’s Retreat of the ten thousand, where tho Greeks passed a. ruined city having walls and defences of great strength. The historian explains that its capture and destruction were due to the besieged garrison being thrown into confusion by the disappearance ot’ Hie sun. In this there is no doubt cither about the totality or the exact position of the city, and thus the line of central eclipse and consequently the moon's position can bo determined on a date in tho year 557 B.U. It may he added that Dr Fotheringliam has only dealt with a few of the occultations recorded, and that there is a promise of further .communications on the subject. The British Astronomical Association at their meeting on February 24 dealt with a munlicr of short papers. There way one oil the subject of Lunar Formations, discussing the theories of volcanic action and of meteoric impact. Then came :i. paper by Air Whitniell on penumbral eclipses of tho moon, showing how frequently the moon passes through the earth’s penumbra but escapes the shadow which would produce the better-known form of lunar eclipse There are no less than four penumbra! eclipses during the present year, namely, on January 31. March 2, July 2(i and August 25, but tho inoon will not enter the earth's shadow again until January 20. 1916. The other papers were all short and dealt with a variety of subjects, A*ariable stain, the Zodiacal light, a remarkable solar prominence, tho transit. of Mercurv last November, Saturn’s rings, and the forms of some recent sunspots. Professor Pickering recently put the question to the directors of several observatories, ‘‘What work would you undertake if you were offered a grant of 1000 dollars a year for five years?” He has now published the replies in one of the scientific publications, and those show that quito a number of useful researches might be undertaken with this very small subsidy. Indeed, tho most- striking feature about it is the moderation of tho demands of science for as an editorial comment nuts it! Hie whole five payments would he less than the cost of ammunition ] for a big field gun for one day. This ! recalls a remark attributed to Dr j Ritchey some years ago. when discussing "the reflecting telescope of Sft aperture which ia being constructed for | Mount Wilson Observatory. Tho ma- j tc-riala themselves are costly, and seve- ( rnl years of skilled labour have to be I brought into account, finally tho complete telescope has to ho transported I to the top of Mount AVilson, 5900 ft j above sea level. It may seem either highly expensive or very cheap ac-‘ coidihg to the point of view, for the [ < r.tire estimate is only four per cent . upon the cost of a modern battlesliip of the Dreadnought type.