14 



KNOWLEDGE. 



January, 1915. 



THE FACE OF THE SKY FOR FEBRUARY. 



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



Table 1. 



Greenwich 

 Noon. 

 Feb. 5 



,, ID ...... 



., 15 



, zo 



. 25 



Sun. 

 R.A. Dec. 



21 12*3 S.i6'2 



2T 32-3 146 



2 1 52"0 i2'g 



22 II "4 II '2 

 22 3o*4 S. 9"4 



Moon. 

 R.A. Dec. 



13 18*6 S. i3'i 

 18 173 S. 27"6 

 22 50'o S. 5'9 

 2 36"i N.20"7 

 7 8'o N.26*4 



Mercury. 

 R.A. Dec. 



h. m. a 



22 22'4 S. q'8 



22 34-q 7-1 



22 ^2'2 6"0 



22 i6'o 6'8 



21 56*0 S. 8"g 



Venus. 

 R.A. Dec. 



h. m. 



17 55"o 



18 16-7 

 iS 39'o 

 ig 1-8 



19 24-9 



S.ig-S 

 20 ■ I 



20'2 

 20*1 



S.ig-S 



Saturn. 

 R.A. Dec. 



h. in. 

 5 4^'7 

 5 41 'o 

 5 40 '4 

 5 40*1 

 5 40 'o 



N.22-4 



22*4 

 22-4 

 22 "4 



N.22*4 



Neptune. 

 R.A. Dec. 



h. m 

 8 2-6 



8 2*1 



8 1-6 

 8 i-i 

 8 o'6 



N.20*I 

 20"I 

 20*1 

 20'2 



N.20"2 



Table 2. 



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. 

 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 iii, e stand for morning, evening. The day is 



taken as beginning at midnight. 



Thk Sun is moving Northwards more rapidly. Its semi- 

 diameter diminishes from 16' 16" to 16' 10". Sunrise changes 

 from 7" 43-° to 6" 50"" ; sunset from 4'' 45" to 5" 36". 



Annular Eclipse of the Sun on Feb. 14th. — The 

 central line crosses West Australia and New Guinea, The 

 following points lie on it ; 114° 14' E., 29° 17' S. ; 124° 43' E., 

 20° 2' S. ; 132° 3' E., 12° 11' S. ; 141° 24' E., 3° 8' S. Partial 

 eclipse is visible throughout Australia, Tasmania, Malay 

 Archipelago, and Madagascar. 



Mercury is an evening star till the 20th. 55' North of 

 Jupiter on 2nd. Semi-diameter increases from 3" to 5". 

 Illumination diminishes from J to zero, and then rises to tV- 



Venus is a morning star, at Greatest Elongation, 47° W., 

 on 6th. Illumination increases from i to *. Semi-diameter 

 diminishes from 13" to 10". 



The Moon. — Last quarter 7^ 5" 11° 



m. New 14'^ 4'' 

 31™ III. First quarter 22" 2" 58"° m. Perigee 7'^ l" c. 

 Apogee 21'' 6^ in, semi-diameter 16' 10", 14' 48" respectively. 

 Maximum librations 7^ 7" N., 14" 5° W., 21" 7° S., 27" 6° E. 

 The letters indicate the region of the Moon's limb brought 

 into view by libration. E.; W. are with reference to our 

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

 (see Table 4). 



Mars is invisible, in conjunction with Sun Dec. 24th. 



Jupiter is in conjunction with the Sun on 24th, and is 

 therefore practically invisible this month. 



Saturn is between Taurus and Gemini. In perihelion on 

 21st. Stationary on 26th. Polar semi-diameter 9". Major 

 axis of ring 44", minor 20". Angle P-5°-7. 



Eastern elongations of Tethys (every 4th given) l" 2'' -8 m, 

 S" 4''-0 c, 16" 5''-2 in, 23" 6''-4 e; of Dione (every 3rd 

 given) 3" l'" -9 e, 11" e*" -9 e, 19" midnight, 28" S"-! m ; of 

 Rhea (every 2nd given) 8" 8" -5 w, 17" 9'" -3 w,26" 10''-2 m. 



For Titan and Japetus E., W. stand for East and West 

 elongations, I. for Inferior (North) conjunction, S. for Superior 

 (South) conjunction. Titan 4" 0''-l e E., S<i ll'''7;n I., 



Table 3. Long-period Variable Stars. 



Special attention should be given to Mira Ceti, which will reach its Maximum in February. It must be 



observed as early in the evening as possible. 

 Night Minima of Algol 1" 3"-0m, 3" iP'-Se, 6" 8" -6^, 9" 5''-4e, 21" 4''-7w,24" l^-S »t, 26" 10" •3c. 



Period 2" 20" 48" -9. 

 Principal Minima of /3 Lyrae February 3" lO^e, 16" S"i'.. Period 12" 21" 47'"-5. 



