140 



KNOWLEDGE. 



April, 1913. 



Being south of Sun, it is less well placed for Northern 

 observers than it was as an evening star. 



The Moon.— New 6 d 8 h 24 m m ; First Quarter 13 d ll h 45 m m : 

 Full 20 d 7 h 18 m m; Last Quarter 28 d h 4 m w. Perigee 

 16 d 2 h ra, semi-diameter 16' 15". Apogee 28 d 8 h w, semi- 

 diameter 14' 49". Maximum Librations, 7 d 5° E, 9 d 7° S., 

 22' 1 5° W., 22 li 7° N. The letters indicate the region of 

 the Moon's limb brought into view by libration. E. VV. are 

 with reference to our sky, not as they would appear to an 

 observer on the Moon. 



Mars is a morning Star, but not yet well placed for obser- 

 vation. 



Ceres and Pallas are well placed for observation. They 

 are of magnitude 7 and 8 respectively. 



Jupiter is a morning star. Polar semi-diameter, 20". 

 Table 28. 



Configurations of Jupiter's satellites at 2 h m for an inverting 

 telescope. 



Satellite phenomena visible at Greenwich, l d l h 39 m I. Tr. E-, 

 2 h 58 m II. Sh. I.; 3 d 2 h 29 m II. Oc. R. ; 7 d h 36 m 43 s 

 III. Ec. R., 2 h ll m III. Oc. D.; 2 h 54 m 46 s I. Ec. D. ; 8 d l h ll m 

 I. Tr. I., 2 h 19 m I. Sh. E., 3 h 20 ,n IV. Oc. D., 3 h 29 m I. Tr. E. ; 

 9 d h 47 m I. Oc. R.; 14 d l h 37 m 25 s III. Ec. D. ; 15 d l h 56 m 

 I. Sh. I., 2 h 59 m I. Tr. I.; 16 d l h 24 m IV. Sh. I., 2 h 36 m 



I. Oc. R.. 3 h 31 ra IV. Sh. E. ; 16 d ll h 44 ra e I. Tr. E. ; 

 17 d 2 h 27 m 58 s II. Ec. D. ; 19 d 0" 16 m II. Sh. E., 2 h 19 m 



II. Tr. E. ; 22 d 3 h 49 m I. Sh. I.; 23 d l h 10 ra 52 8 I. Ec. D. ; 



23 d ll h 13 m e I. Tr. I.; 24 d h 35 m I. Sh. E. l h 31 m I. Tr. E. ; 



25 d 2 h 14 m III. Tr. E. ; 26 d h 3 m II. Sh. I.. l h 52 m II. Tr. I., 



2 h 52 m II. Sh. E. ; 30 m 3 h 4 m 46 s I. Ec. D. ; 31 d h ll m I. Sh. 



I., h 59 m I. Tr. I., 2 h 28 m I. Sh. E., 3 h 17 m I. Tr. E. ; 

 31 d n h 16 m c IIX Sh J 



All the above, except the three marked e, are in the morning 

 hours. 



Saturn is invisible, being in conjunction with the Sun on 

 the 29th. 



Uranus is a morning star, coining into a better position 

 for observation. 



Neptune is an evening star and was stationary on April 

 4th. 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) : — 



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. 12 h to 16 h , next month 14 h to 18 h , and 

 so on. 



Table 29. Non-Algol Stars. 



