April, 1904.] 



KNOWLEDGE cS: SCIEXTIEIC NEWS. 



69 



The Face of the Sky for 

 April. 



By W. SiiACKLETON, F.K.A.S. 



The Si'N. — On the ist the Sun rises at 5.3S, and sets 

 at 6.31 ; on the joth he rises at 4.37, and sets at 7. ly. 



The equation of time is negligible on the 15th and 

 i6th, hence these are convenient days for the adjiistniont 

 of sun dials or for laying down a meridian line to a close 

 approximation. 



SunsjXits are of frequent occurrence ; their positions 

 may be located by the use of the following table : — 



The Moon : — 



Date. 



Phases. 



April 7 . . 

 .. 15 •• 

 .. 23 .. 

 ., 29 .. 



(T Last Quarter 



• New Sloon 



]) First Quarter 



O Full Moon 



H. M. 



5 .53 P-m- 



9 53P-m 



4 55 a.m. 



10 36 p.m. 



Occulta.tions. 



The following are the principal occultations visible at 

 Greenwich at convenient times : — 



Saturn is a morning star, rising at 3.15 a.m. near the 

 middle of the month ; he is situated in Capricormis, and 

 conseciuently low down in the sky. 



I'ranus rises on the isl alunit 1.30 a.m., ami on the 

 30th at 11.30 p.m.; througlioul llie month the pi. met is 

 close to 4 Sagitlarii, Ix-iiig only si.\ minutes wt-st anil 

 having approximately the same declination as the star. 



Neptune is getting more to the west, and sets about 

 .S.30 p.m. near the middle of the month. He is describ- 

 mg a retrograde path towards >; Geminorum ; his posi- 

 tion with respect to that star may be seen on reference to 

 the chart given in the January number. 



IMeteor SiiowiiKs : — ■ 



The Sr.\RS. — About the middle of the month at 9 p.m. 

 thepositionsof the principal constellations are as follows: 

 Zenith . Ursa Majur. 

 North . I'nlaiis : to the right, Ursa Minor and 



Draco; to the left, Cassinpeire and I'crseus ; 



below, Cepheus and Cygnus. 

 South . Leo and Hydra; to the south-east, \'irgo; 



to the south-west, (leniini (high up), Procynn, and 



Siriiis (setting). 

 West . Taurus, Pleiades, and Orion, all rather 



low down. 

 East . Antiinis, Corona, and Hercules; to the 



north-east, Vi-ga rising. 

 Minima of Algol may be observed on the 7th at 

 10.38 p.m., loth at 7.27 p.m., and 30th at y.io p.m. 



Date 



Star's 

 Name. 



49 Librae . . 

 B.A.C. 339« 

 m Virginis . . 

 B..\.C 4S2S 



Magni- 

 tude. 



5-6 

 5-9 

 53 

 6-0 



iJisappcarance. 



Mean Time. 



II. 4 p.m. 



925 pm- 



10.6 p m. 



9 40 p.m. 



Angle from 

 N- point 



94 

 118^ 



Reappearance. 



103- 

 75' 



Mean Time. 



12.9 a.m. 

 10.33 p.m. 

 11.18 p.m. 

 10.37 p.m. 



Angle from 

 N. point. 



Moon's 

 Age. 



297 

 284° 



303" 

 327° 



d. h. 



17 17 



9 o 



13 o 



14 o 



The Planets. — Mercury should be looked for in the 

 N.W. shortly after Sunset from the 15th to the end of the 

 month. .Vbout this time the planet is in the most favour- 

 able position for observation for the present year, and sets 

 about two hours after the sun. On the 21st he arrives at 

 greatest easterly elongation of 20 1 1', and although this 

 is not so large as the autumnal elongation, the greater 

 inclination of the ecliptic to the horizon at this time puts 

 the planet into a much more favourable position tor 

 observation. 



The diatneter of the disc is 8"-o. 



\'enus cannot readily be observed, as she only rises 

 about half an hour in advance of the Sun, and is thus 

 lost in the bright dawn. 



Mars is practically unobservable, as he sets before it 

 is really dark. 



Jupiter was in conjunction with the Sun towards the 

 end of last month, and is therefore too close to the Sun 

 for observation. 



Tei.i;sc()Mc Oi3Jec'is: — 



Double Stars:—-, N'irginis, Xll.'' 37"% S. o'-' 54', mags. 

 3, 3 ; separation 5"'7. Hinary system ; both components 

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



3-m. 



An eyepiece of a power of 30 or 40 is reijuired 

 to effect separation. 



rr Bootis, XIV.'' 36™, N. 16^ 53', mags. 4, 6; separa- 

 tion 6". K'equires a power of about 40. 



I Boc/tis, XIW' 41"', N. 27° 30 , mags. 3, 6i; separa- 

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

 the brighter comiwjnent being yellow, the other blue green. 



;. Bootis, XI\'.'' 47™, N. 19' 31 , mags. 5, 7; separa- 

 tion, 2"'4. Binary ; one component being orange, the 

 other purple. 



Clusters :— M 3 {Canes Vauitici). XUl.'' 38"% N. 28 48'. 

 This object, though really a globular cluster of myriads 

 of small stars, appears more like a nebula in small tele- 

 scopes. It is situated between Cor Carnii and Anturus, 

 but rather nearer the latter. 



