THE HEAVENS IN AUGUST 



101 



hours of the night go on, the radiant 

 rises higher and higher in the sky, the 

 most favorable hours of all for obser- 

 vation being between I o'clock and 

 sunrise, though occasional stars may 

 be seen at all hours of the night. 



These shooting stars are caused by 

 the collision of the earth with an im- 

 mense swarm of little particles which 

 are following the same path about the 

 sun as the third comet of 1862, and are 

 very probably the remains of this 

 comet, which has been torn apart and 

 stretched out along its path by the tidal 

 .action of the sun. As each dark and 

 cold little particle of the swarm 

 ploughs through the air of our swiftly 

 moving earth it is burnt up by the 

 friction and is seen by us as a shooting 

 star. 



us the occupation is not visible, the 

 moon passing below the star. Could 

 we journey to the southern hemisphere 

 on the night of any of the occultations 

 we would see the moon apparently ris- 

 ing in the sky, owing to our displace- 

 ment on the earth, and in time it would 

 be seen to hide the star from view. On 

 the morning of August 7 the moon will 

 similarly pass squarely over the 

 Pleiades as viewed from the southern 

 hemisphere, but as seen from the north- 

 ern latitudes it will appear to pass be- 

 low them. 



When any star is thus hidden by the 

 moving moon it almost always disap- 

 pears instantaneously ; it goes out as 

 suddenly as a flash of lightning ; there is 

 no hanging on the edge of the moon and 

 no gradual fading away. Even when 



EAST 

 Figure 2. The eastern heavens at 1 o'clock A. M., August 1. 



OCCULTATIONS. 



The occultation of Antares by the 

 moon, which occurred on the evening 

 •of June 26, was witnessed by many 

 •observers in the western part of our 

 country, but in the east the skies were 

 so generally cloud}- that but few saw 

 this interesting phenomenon. The path 

 of the moon among the stars is at pres- 

 ent changing so little and the occulta- 

 tion was so nearly a central one that 

 it will be repeated each time that the 

 moon in its monthly course reaches 

 this part of the sky during August, 

 September and October. But by care- 

 ful watching the observer may notice 

 that each month the path of the moon 

 in this part of the sky lies a little lower 

 down than the path pursued the month 

 previously. Consequently, as seen by 



the phenomenon is photographed by 

 an apparatus containing a revolving, 

 very sensitive, photographic plate, no 

 gradual fading can be detected. The 

 stars shines out in full brightness until 

 the body of the moon actually hides it 

 from view. This shows us clearly that 

 the moon has no atmosphere, or, at 

 most, an inconceivably rare one, for 

 had our satellite an atmosphere only 

 one-two-thousandth part as dense as 

 our own, there would be a distinct 

 lingering and fading away of stars on 

 its advancing edge. 



A phenomenon of even more interest 

 is the occultation of a star by a planet. 

 This has been several times observed, 

 but owing to the very much smaller ap- 

 parent sizes of the planets and their far 

 slower motions, it is witnessed far less 



