THE HEAVENS FOR JANUARY 



A35 



move over the little group of the 

 Pleiades, although observers in the 

 eastern part of the United States will 

 not first witness this most interesting 

 occurrence until next September. 



Qf the five eclipses of the present 

 year there will be three of the sun, 

 which will be wholly invisible to us, 

 and two interesting total eclipses of the 

 moon. The latter to observers in the 

 eastern part of our country will be seen 

 to begin about sunrise, just as the full 

 moon is setting. They will, however, 

 be wholly visible throughout the west- 

 ern part of the United States. 



It is also of interest to notice the re- 

 markably early occurence of Easter 

 during the present year. The time of 

 this festival has been fixed as the Sun- 



1862. This body was known to be pur- 

 suing a great, closed path around the 

 sun, making a complete revolution in 

 the course of 13 years. At its present 

 return to the vicinity of the earth it 

 was at no time bright, and it has now 

 moved into the southern sky and is 

 wholly invisible to observers in north- 

 ern latitudes. 



On November 2 a third faint comet 

 was discovered in the constellation 

 Hercules. This body was seen to be 

 moving' very rapidly eastward and 

 southward among the stars, its ex- 

 tremely rapid apparent motion being 

 due to the fact that it and the earth 

 when nearest together were moving in 

 almost exactly opposite directions. On 

 Tanuarv 1. it will be found low in the 



DEC. I 



NOV. 14°^ 



2l>* 



Path cf Earth's Oncrr 



. 



Figure 3. Showirg the path of the third comet of 1912 about the sun. 



day following that full moon which 

 first occurs after the passage of the 

 center of the sun across the ecpiator, at 

 the point V, Figure I. It happens that 

 this year the center of the sun reaches 

 this point at 18 minutes past midnight 

 on the morning of Friday, March 21, 

 and that a full moon occurs but one 

 day later, — at 7 o'clock on the follow- 

 ing Saturday. Consequently the fol- 

 lowing clay is Easter. Had the fu'b 

 moon occurred a day and a half earlier, 

 our Easter of this year would have oc- 

 curred about a month later than it 

 does. 



THE NEW COMETS. 



Nearly nine months of the year 1912 

 had passed before the first comet of 

 the year was discovered. This is a 

 faint, telescopic object, now moving 

 northward through the constellation of 

 the Dragon, and rapidly receding from 

 the earth. 



The second comet to be discovered 

 has now been found to be identical with 

 a periodic comet first seen in the year 



southwestern sky, almost exactly one 

 hour to the west of the star C, Figure 

 1, but at this time it will probably be 

 invisible even in the telescope, on ac- 

 count of its great distance from the 

 earth. 



One of the most interesting of all 

 the comets is the comparatively small 

 object known as Encke's Comet. The 

 motion of this body was long ago so 

 disturbed by the planet Jupiter that 

 the comet was thereafter added to the 

 bodies of our solar system, and forced 

 to revolve about the sun in a path so 

 small that an entire revolution about 

 the orbit is performed in only three and 

 one-third years. This is by far the 

 shortest period of any known comet ; 

 as the orbit is a much flattened curve 

 whose nearest vertex is within the orbit 

 of the planet Mercury and whose 

 farthest vertex is but four hundred mil- 

 lions of miles from the sun, it follows 

 that during much of the time the comet 

 is near enough to the earth to be seen 

 bv us. 



