January, 1912. 



KNOWLEDGE. 



Figure 4. Double Stars between Right Ascension 7" and 9". 



Mercury is badly placed for Northern observers, but may 

 be seen as a morning star at the beginning of the month. It 

 presents a nearly full disc, being in superior conjunction on 

 March 1st. It is on the same parallel as \'enus on February 

 4th, and may be found by pointing a telescope at Venus, and 

 leaving it stationary for l"" 24"". 



Venus is also rather badly placed, being South of the 

 Sun ; * of the disc is illuminated, the diameter diminishing 

 from 14 V' to 12 J". 



Mars is still a bright evening star in Taurus, but is rapidly 

 receding from us. The diameter diminishes from 10" to 7". 

 The seasons on the planet correspond to the first half of April 

 on Earth. Both poles are invisible, since the Sun and Earth 

 are on opposite sides of the planet's e<iuator. 



Ceres and Vesta are both \vell placed, the latter being in 

 opposition on February 16th. Its magnitude is 62, so that it 

 might be glimpsed by a keen eye without optical aid. The 

 positions of the two planets are sufficiently shown by maps 

 indicating the configuration of surrounding stars. Vesta is 

 50' South of 7 Leonis, on February 9th. 



Jupiter is better placed than last month, but its South 

 decUnation is a drawback to Northern observers. The 

 equatorial diameter increases from 34" to 36^". The polar 

 is 2i" less. Defect of illumination nearly i ". The diagram 

 shows the configurations of the four large Satellites at 5"" in. 



Table 5. 



Phenomena visible at Greenwich: — I. Sh. E. 1'' 4'' 12"" 



II. Sh. I. 5" 16'", I. Tr. E. 5" IS"'; II. Oc. K. i"" 4" 30"" 



I I I. Ec. D. 7" 30"" 22" ; II I. Tr. E. 7" i" 43'°, I. Ec. D. 6" 43'" 52' 

 I. Sh. I. «•' 3" 52"". I. Tr. I. 5" 1"". I. Sh. E. 6" 5"", I. Tr. E. 7" 14" 

 I. Oc. R. 9''4''32"'; II. Oc. R. lo" 7" 10"'; III. Tr. 1. 14" 5" 56"" 

 I. Sh. I. 15" 5" 45'". I. Tr. I. 6" 57"; I. Ec. D. 16" 3" 5" 51" 



I. Oc. R. 6*' 29" ; 1. Tr. E. 17" 3" 39"", II. Ec. D. 4" 49'" 54" 



II. Tr. E. 19"4'' 52"; Ill.Sh. I. 21" 5" 5'°, III. Sh. E. 6'' 59" 



