THE FACE OF THE SKY FOR APRIL. 



By A. C. D. CROMMELIN, B.A., D.Sc, F.R.A.S. 



Table 14. 



Dale. 



.■^pr. 



Greenwich 



Noon. 



6 ..lyy.".'.'.'/.'..] 

 II 



i6 



21 



26 



Sun. 

 R.A. Dec. 



N. 



h. m. 

 °39'3 



o57'5 6-1 



I 15-8 8 o 



I 34-2 98 



1 52-8 11-6 



2 11-5 N.13-3 



Moon. 

 R.A. Dec. 



13 38-2 S. 15-1 

 18 50-2 S. 26-5 

 23 84 S. 35 

 2 54 '6 N.21-9 

 7 16-5 N.25-3 

 II 28-3 N. 0-8 



.Mercury. 

 R.A. Dec. 



7-8 

 S'o 



h. m. 



23 ii'i S. 



23 58-6 



o 8-1 .S. 



396 N. 1-9 



1 I3'4 , 5'9 

 I 50-0 N.10'2 



Venus. 

 R.A. Dec. 



22 31-0 



22 53-5 



23 15-3 

 23 38-0 



o o-i 



S.I I -9 

 lo-i 

 8-1 

 6-0 



3 '9 

 S. 1-6 



Jupiter. 

 R.A. Dec. 



h. m. 

 23 0-4 

 23 4 '6 

 23 8-7 

 23 12-8 

 23 16-7 



7 4 

 70 

 6 6 

 6-1 

 5'7 

 5 '4 



Saturn. 

 R.A. Dec. 



h. m. 

 5 44-6 

 5 46-0 

 5 47 '6 

 5 49 '3 

 5 5>'' 

 5 53'i 



N.22-6 



22-6 

 22-6 

 22-6 

 22-6 



N.22-7 



Neptune. 

 R.A. Dec. 



h. m 



738-7 



758-6 



758-6 



7 53-7 



758-8 



N.20-3 

 30-3 

 20-3 

 20-3 

 20-3 



7 59-0 N.20-3 



Table 15. 



P is the position angle of the North end of the body's axis 

 measured eastward from the North point of the disc. B, L 

 are the helio-(planeto-)graphical latitude and longitude of the 

 centre of the disc. In the case of Jupiter System I refers to 

 the rapidly rotating equatorial zone, System II to the tem- 

 perate zones which rotate more slowly. To find intermediate 

 passages of the zero meridian of either system across the 

 centre of the disc, apply to Ti Ta muhiples of 9" 50"° -6, 

 9" 55"- 8 respectively. 



For the future the data for the Moon and Planets in the 



Second Table will be given for Greenwich Midnight, i.e., the 



Midnight at the end of the given day. 



The letters in, c stand for morning, evening, 

 taken as beginning at midnight. 



The dav is 



The Su.\ is moving Northwards at a slackening pace. 

 Its semi-diameter diminishes from 16' 2" to 15' 54". Sunrise 

 changes from 5" 42" to 4" 36" ; sunset from 6" 28" to 7" 18". 



Mercury is a morning star till May 1, when it is in 



superior conjunction with the Sun. Semi-diameter diminishes 

 from 3" to 2i". Illumination increases from | to Full. 



Venus is a morning star. Illumination increases from 

 TB to T^. Semi-diameter diminishes from 8" to 7". 



The Moon.— Last quarter 6" 8" 12" e. New 14'' 11" 36" m. 

 First quarter 22'* 3" 39" e. Full 29'' 2" 19" e. Perigee 

 l** 12" e. Apogee IT' 4" e. Perigee 30'' 7" m, semi- 

 diameter 16' 34", 14' 44", 16' 44" respectively. Maximum 

 librations3''7°N., 8" 6°W., 17" 7''S.,24'' 8° E.,30''6°N. The 

 letters indicate the region of the Moon's Hmb brought 

 into view by libration. E., \V. are with reference to our 

 sky, not as they would appear to an observer on the Moon 

 (see Table 16). 



Mars is still badly placed, having been in conjunction with 

 the Sun on Dec. 24th. 



Jupiter was in conjunction with the Sun on Feb. 24th, 

 and is therefore difficult to observe this month. 9' North of 

 Venus on 15th, 4" e. Equatorial diameter 35", Polar 33". 



Table 16. Occultations of Stars by the Moon visible at Greenwich. 



From New Mooa to Full disappearances occur at the Dark Limb, from Full to New reappearances. 



90 



