94 



KNOWLEDGE c^ cSCIEXTIFIC NEWS. 



[April, 1905. 



The Face of the Sky for April 



By W. Shackleton, F.R..\.S. 



The Sun. — On the ist the Sun rises at 5.38, and sets at 

 6.31 ; on the 30th he rises at 4.37, and sets at 7.19. The 

 equation of time is negligible on the i6th. Sunspotsand 

 facukt-are usually conspicuous on the solar disc, marking 

 a return to nia.ximum activity, whilst prominences also 

 continue to be numerous. 



For plotting the positions of spots, &c., the following 

 table gives the necessary data : — 



The Moon : — 



OccuLTATiONS. — The only bright star occulted during 

 convenient hours is 7 Virginis (mag. 4-0) at 8.18 p.m. on 

 the 17th. 



The Planets. — -Mercury is an evening star in Aries, 

 being at the most favourable eastern elongation of the 

 year on the 4th, when he sets at 8.30 p.m. He should 

 be looked for immediately after sunset, nearly due west 

 and rather low down. On the evening of the 6th he is 

 7* N. of the thin crescent moon. The planet is in 

 inferior conjunction with the Sun on the 23rd. 



Venus continues to be a brilliant object in the evening 

 sky during the earlier part of the month, and sets about 

 10.10 p.m. on the ist. The planet stts earlier each day, 

 and is in conjunction with the Sun on the 27th. As seen 

 in the telescope, the planet exhibits a crescent which is 

 thinning out but increasing in apparent diameter ; on the 

 15th, 0-05 of the disc is illuminated, the diameter being 55". 



Mars is not in a favourable position for observation, 

 being situated low down in Libra. About the middle 

 of the month he rises at 9.30 p.m. and comes to the 

 meridian at 1.50 a.m. 



Jupiter is practically out of range for observation, 

 setting at 8.30 p.m. on the 7th ; from this date to June 

 1st the satellites are invisible, as the planet appears too 

 near the Sun. The moon is near Jupiter on the evening 

 of the 6th. 



Saturn is a morning star in Aquarius, rising about 

 3.45 a.m. near the middle of the month. 



Uranus does not rise until after midnight ; he is situated 

 low down in Sagittarius. 



Neptune is on the meridian before sunset, but is ob- 

 servable in the west until midnight, as he sets about 

 I a.m. on the 15th. The planet is near ^ Geminorum, 

 and can most readily be found by reference to that star. 



Right Ascension. Declination. 



Neptune (.\pril 15). e*" 24"" 16* .. N. 22° 2i' 51" 



II Geminorum . . e^ 17"' 13' . . N. 22° 33' 38" 



Meteor Showers: — 



Minima of Algol may be observed on the 9th at 11. 5 

 p.m., and on the 12th at 7.54 p.m. 



Telescopic Objects : — 



Double Stars. — y Virginis, XII.'' 37™, S. o' 54', mags. 

 3, 3 ; separation 5"-9. Binary system ; both components 

 are yellow, though one is of a deeper hue than the other. 

 An eyepiece of a power of 30 or 40 is required on a 3-in. 

 to efiect separation. 



IT Bootis, XIV.'' 36"", N. 16° 53 ', mags. 4, 6 ; separa- 

 tion 6". Requires a power of about 40. 



f Bootis, XIV.'' 41'", N. 27° 30', mags. 3, 6i; separa- 

 tion 2"'7. Very pretty double, with good colour contrast, 

 the brighter component being yellow, the other blue 

 green. 



f Bootis, XIV.'' 47"", N. 19° 31', mags. 5, 7; separa- 

 tion, 2"-5. Binary ; one component being orange, the 

 other purple. 



Clusters.— M 3 (Canes Venatici), XIII." 38-", N. 28" 

 48'. This object, though really a globular cluster of 

 myriads of small stars, appears more like a nebula in 

 small telescopes. It is situated between Cor Caroli and 

 Arcturus, but rather nearer the latter. 



Royal Institltion. — The following are the Lecture 

 Arrangements at the Royal Institution, before Easter: — A 

 Christinas Course of Lectures (eNperimcntaliy illustrated and 

 adapted to a juvenile auditory) on Ancient and Modern 

 Methods of Measurint; Time, by Mr. Henry Cunynghamc; 

 Professor L. C. Miall, Fnllcrian Professor of PliysioloKy, K.I., 

 Si.x Lectures on Adaptation and History in the Structure and 

 Life of Animals ; Professor Karl i'l'arson, Tbrci- Lectures on 

 Some Recent Hiometric Studies; Professor W. V.. Dalby, Two 

 Lectures on Engineering; Mr. A. H. Savage Landor, Two 

 Lectures on E.\ploration in the Philippines; Mr. Churton 

 Collins, Two Lectures on (1) The Religion of Shakespeare, 

 [z) The Philosophy and Significance of "The Tempest"; 

 Professor W. Schlich.Two Lectures on Forestry in the British 

 ICmpire ; Mr. J. J. IL Teall,Two Lectures on Recent Work of 

 the Geological Survey ; Professor H. H. Turner, Three Lec- 

 tures on Recent Astronomical Progress; Professor R. Meldo'a, 

 Two Lectures on Synthetic Chemistry (Experimental); Sir 

 Alexander Mackenzie, Three Lectures on the Hoheniian 

 School of Music (with Musical Illustrations); Mr. 1). G. 

 Hogarth, Two Lectures on Archeology; Professor J. J. 

 Thomson, Three Lectures on Electrical Properties of Radio- 

 active Substances; and the Rt. Hon. Lord R.iyleigh, Three 

 Lectures on Some Controverted Questions of Optics. The 

 I'riday Evening Meetings will begin on Janu.iry 20, when a 

 Discourse will be delivered l)y Professor Sir James Dew.ir on 

 New Low Temperature Phenomena; succeeding Discourses 

 will probably be given by Dr. E. A. Wilson, Mr. Cecil Smith, 

 Mr. J. W. Gordon, Professor H. Marshall Ward, Chevalier G. 

 Marconi, Professor J. J. Thomson, Sir Squire Bancroft, Pro- 

 fessor G. H. Bryan, Professor J. Wright, Professor T. C. 

 Allbutt, the Rt. Hon. Lord Kayleigh, and other gentlemen. 



