58 



KNOWLEDGE. 



February, 1913. 



6 d 8 h w, semi-diameter 14' 43" ; Perigee 21 a Noon, semi- 

 diameter 16' 41". Maximum Librations, l d 7°N, 14 d 8° E., 

 16 d 7° S., 27 d 7°W., 28 d 7° N. 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. 



Mars is a morning Star, but practically invisible. 



Jupiter is still badly placed, having been in conjunction 

 with the Sun on December 18th. It is a morning star. Polar 

 semi-diameter, 16|". 



March 9' 6 h -7 e, 18 d 7 h -8 e, 



semi-diameter 8". The major axis of the ring is 41", the 

 minor axis 17". The ring is now approaching its maximum 

 opening and projects beyond the poles of the planet. 



East elongations of Tethys (every fourth given). March 

 4 d ll h -5 w,12 d h -9 m, 19 d 2 h -2 e, 27" 3 h -5m. Dione (every 

 third given). March l d ll"-2 e, 10 d 4 h -3 m, 18 d 9 h -5 in, 

 26 d 2 h -7 e. 



Rhea (everv second given) 

 27 d 8 h -8 e. 



For Titan and Iapetus, E. W. mean East and West 

 elongations, I. S. Inferior and Superior Conjunction, Inferior 

 being to the North, Superior to the South. Titan, 3 d 3 h - 1 e E., 

 7 d 3 h -7 e I., ll li h -l e W., 15 d ll h -3 m S., 19 d 2 h -9 e E., 

 23 d 3 h -7 e I., 27 d h -2e W. Iapetus ll d 9 h -6 m W.. 31 d 7 h -4 

 e S. 



Uranus is invisible, having been in conjunction with the 

 Sun on January 24th. 



Neptune was in opposition on January 14th. Its motion 

 may be traced on the map of small stars which was given in 

 " Knowledge" for December, 1911, page 476. 



Meteor Showers (from Mr. Denning's List) : — 



Configurations of Jupiter's satellites at 5 h m for an inverting 

 telescope. Table u 



Satellite phenomena visible at Greenwich, 2 d 5 b 6 m IV. Oc. 

 R. ; 5 d 6 h 9 m II. Sh. I. ; 6 d 4 h 19 m 44 s I. Ec. D. ; 7 d 4 h 16 m III. 

 Tr. I. ; 4 h 58 ra I. Tr. E. ; 5 h 54 m II. Oc. R. ; 13 d 6 h 13 m 30 8 I. 

 Ec. D. ; 14 d 3 h 39 m III. Sh. I.; 4 h 38 m I. Tr. I.; 5 b 42 m 

 I. Sh. E.; 15 d 4 h 10 m I. Oc. R. ; 21 d 5 h 18 m I. Sh. I.; 6 h 0"° 

 46" II. Ec. D.; 23 d 3 h 14 m II. Tr. I.; 3 h 20 m I. Tr. E. ; 

 3 h 26 m II. Sh. E. ; 29 d 4 h 29 m 21" I. Ec. D. ; 30 d 2 h 57 m I. Tr. 

 I.; 3 h 15 m II. Sh. I.; 3 h 57 m I. Sh. E. ; 5 h 14 m I. Tr. E. 



All the above are in the morning hours. 



The first eclipse of IV. occurs on the 18th ; the first transit 

 occurred February 4th. 



Saturn is an evening Star, 6° South of the Pleiades. Polar 



Double Stars and Clusters.— The tables of these given 

 last year are again available, and readers are referred to the 

 corresponding month of last year. 



Variable Stars. — Tables of these will be given each 

 month ; the range of R.A. will be made four hours, of which 

 two hours will overlap with the following one. Thus the 

 present list includes R.A. 8 h to 12 h , next month 10 h , to 14 h , and 

 so on. In the case of Algol variables, the time of one 

 minimum is given where possible, and the period. Algol, 

 owing to its brightness, will be given for wider limits. 



Algol Stars. 



Non-Algol Stars. 



Table 15. 



