ASTRONOMICAL NOTES FOR MAY.

New Zealand Herald, Volume XLII, Issue 12856, 3 May 1905, Page 1 (Supplement)

ASTRONOMICAL NOTES FOR MAY.

[Br S. STUART, BRITISH ASTRONOMICAL

ASSOCIATION.]

Mercury, after a brief and inconspicuous apparition in our western evening sky, haft now retired to the other side of the sun, and become a morning star, as he rises on the Ist at 16 minutes to six a.m., and on the 15th at 10 minutes to five. He will bo in conjunction with the moon about seven p.m. on the 3rd, distant nearly three degrees from her centre, and on the 6th, at halfpast four p.m., ceases his retrograde motion, and becomes direct. By the 9th, between seven and eight a.m., he will have reached hi-; aphelion or greatest distance from the sun in his orbit, whence he proceeds to his maximum elongation or angular distance from that luminary, 25deg. 26m., on the 21st, at half-past ten p.m. This will be the best occasion fo. observers at present, but, beinp in the morning sky and north declination, is not too favourable. On the 29th, between four and five p.m., Mercury reaches .. his greatest heliocentric latitude south, and his movements »o. the month are comprised between the 28th degree of Aries and the 17th degree of Taurus, in the lirsc and fourth degiees or south latitude.

Venus, so long ornamenting our evening sky, has also disappeared, she being now* a morning star, and rising on the Ist at 19 minutes past six, and on the 15th at. 51 minutes past four a.m. Like Mercury, she is in conjunction with tne moon on the 3rd, about midnight, but- separated from on. satellite by nearly nine degrees of latitude. On the loth Venus and Mercury are in conjunction in the 29th degree of Aries, but .separated by nearly six degrees of latitude: and on the 17th, between three and four a.m., Venus becomes stationary, and thereafter direct in her movement. On the 22nd, between one and two p.m., she will pass her descending node, from north to south latitude ; and on the 31st, m, about six a.m., is again in conjunction with the moon —this time separated from, the centre of the lattei by about three degrees. During May Venus will be found receding from the fourth decree ol Taurus to the 29th degree of Aries, whence she moves forward again to the second degree of Taurus, in the fifth degree of north latitude to the second degree south.

Mars is- 'becoming conspicuous in the eastern evening sky at present, since he rises almost at sunset, or 55 minutes after six on the Ist, and 28 minutes after four on the 15th. On the 9th, between seven and eight a.m., he will be in his opposition to the sun, an event which occurs about once in two years, at which'times he is always a conspicuous object in the eastern horizon, and sometimes is such a flaming red star as to cause something like a panic among those who are ignorant of astronomy. Such an instance occurred in the year 1719, at which opposition Mars equalled Jupiter in splendour, but. being of a, blood-red colour, excited tremendous alarm among the peasantry in France. Until the recent discovery of Eros, these positions of Mars were looked upon as the best means of obtaining the sun's parallax, next to the transits of Venus, and the Nautical Almanac gives a table of the stars best to be observed, with the planet for that purpose. As long ago as 1672 this- was perceived by Flamstead, the first Astronomer Royal, and he tells us: "My father's affairs caused me to take a journey into Lancashire, the very day I had designed to 'begin my observations, but God's providence so ordered it- that they gave me an opportunity to visit Townley, where I was kindly entertained by Mr. Townley, with whose instruments I saw Mars, near the middlemost of the three adjacent fixed stars. ' My stay in Lancashire was short. At my return'from there if took his distance from three of them at different times of the night,; whence I determined his parallax, then 25 seconds, equal to his visible diameter, which, therefore, must be its constant measure, and consequently the sun's horizontal parallax, not more* than 10 seconds." It is wonderful that Flamstead should have been so near to accuracy in this instance, but he was not quite correct, for the sun's parallax is 8.9 seconds, and in the present opposition the horizontal parallax of Mars will be 16.2 seconds, and his diameter 17.4 seconds. On the 11th, between nine and ten p.m., he will pass his descending node into south latitude, and on the 18th, about ten a.m., will be in conjunction with the moon, some five degrees > distant from her centre. On the 19.th, at 18._niinntes after six a.m., Mars will be in conjunction with the noted staT Alpha Libra (nearly of the third magnitude), and separated from it by only 23 minutes of latitude to the south; conseouentK he will be seen, quite close to it.on the evenings of the 18l.li and 201 It. Being in onoosition to the suit, he is retrograding, and moves from the 21st degree of Virgo to its 11th degree, in the first degrees of north and south latitude.

Jupiter has also disappeared from our evening sky. after sr long adorning it, and by six p.m. on the 4th he will have reached his conjunction with the sun. On the Ist he will se' at sh. 20m. p.m., and on the 15th at 4b. 7)4m. By about midnight on the 4th the planet will.be in conjunction with the moon, about four degrees to the north of her centre: and on the 21st, also nearly at midnight, there, will be a conjunction of Jupiter and Venus, but they are too near the sun for easy observation, 'and also separated from each other by 7deg. 16m. of latitude. Jupiter will he found during May between the loth and 20th degrees of Taurus, with one degree south latitude.

Saturn is now again making an approach to our eastern skies, as he rises on the Ist at loh. 28m., and on the 15th at eight minutes aflet midnight. There is a slight error in the nautical almanac: announcements concerning him this month, as on page 581 it, is noted that he will be in his quadrature to the. sun. or 90 degrees from the latter, on the 24th : but it- should be only 60 degrees, which is a position dear to astrologers, hut of which our national Ephemeris takes no notice. Saturn moves for the present between the twenty-ninth degree of Aquarius and the second degree of Pisces,' in the second degree of south latitude. ,

The more distant plane:- Herschell now rises on the Ist at Bh. 26m., and on the 15th at 7h. 29m. p.m., being near the star Lambda Sagittarii (third magnitude), and about two degrees to the west and north of it. Herschell will be in conjunction with, the moon on the 21st, between ten and eleven p.m.. and is retrograding in the ninth degree of Capricorn, with the first degree of south latitude. The still more distant planet Neptune is in the opposite horizon, setting at Bh. 26m. on the Ist, and 7h. 45m. on 1 he 15th. His conjunction, with the moon occurs on the 9th, about ten a.m., some four degrees to the north of her centre; and he will lx found in the sixth and seventh degrees of Cancer, with one degree south latitude. The sun is now getting a long way to the north of our celestial equator, and the weather perceptibly colder in consequence. He enters the sign Gemini on the 21st at 31 minutes after six p.m., and dialists will find their solar time fast, of Auckland clocks on the Ist by 11m. 575., on the 15th by 14m. 505., and on the 31st by 13m. 38s. The davs are approaching the shortest, as on the Ist we have only 10 hours 26 minutes of daylight, out of the 24, and on the 15th 9 hours 58 minutes. The rapid course of the moon this month begins on the 2nd at forty-two minutes past two a.m., when she passes her apogee; whence she proceeds to her conjunction with the sun on the sth at twenty minutes after three a.m., in the 14th degree of Taurus. On the 6th, at midnight, she is in her greatest present south latitude, sdeg. 2min., and on the 9th, at Bh. 30m. a.m., is in her greatest northern declination, 18deg. 56m. By the 12th. at sixteen minutes after six p.m., she will be in her first quartei ; and on the 13th, about eight a.m., is in conjunction with the star Alpha Leonis. or the Lion's Heart, of the first magnitude, and will be seen near hipi the preceding and following evenings. ' On the 13th, at Bh. 39m., she will nasi- her ascending node; and on the 15th, a twelve minutes after 10 p.m.. will be on the equator. By the 17th, at 4h. 54m. p.m., she will have reached her peri- { gee; and on the 19th, at six minutes after

nine a.m., will be full in the.2Bth degree of Taurus.. On the 19th, at midnight, she is again in her maximum latitude, this time 5 deg. lm. north. This is followed on the 22nd, at two a.m., by her greatest southern declination, 19deg. On the 29th, at sh. 36m. p.m., she will have returned to her apogee, or greatest distance from us. British astronomers are in the thick of their discussion as to the most convenient positions for observing the coming solar eclipse, the old town of Burgos, in Spain, meeting with most favour, and it is noted that in view of this, hotel charges there are going up rapidly for the occasion.Others say the coast of Labrador will offer advantages, if weather ■'can be depended upon. There is also much discussion as to the supposed discovery of sixth and seventh satellites of Jupiter, which, how-: ever, are much doubted. The lunar eclipse of February 19, which began in the western horizon, and was not observed in Auckland, was very well observed in the Old Country, and lias afforded some discussion by its peculiarities. ■ v;s