TO KNOW THE STARRY HEAVENS 



233 



telescope than at any other time. 



The Planets in 1918. 



Mercury, on January 1, is still an 

 evening star, but it is far too near the 

 sun to be observed. Only two days 

 later it will in fact enter the morning- 

 sky, not to again pass to the east of 

 the sun until March 12. On April 7 

 it will attain its greatest distance east 

 of the sun and in its interesting and 

 rapid oscillations from one side of the 

 sun to the other will similarly reach 



Figure 2. The paths of Mars and Saturn on the 

 Celestial Sphere. 



its greatest eastern elongation on Aug- 

 ust 5 and on November 29. On the 

 first two dates the planet will be above 

 the celestial equator and will easily be 

 found by the observer ; the last elonga- 

 tion, however, will be a far less favor- 

 able one. 



The beautiful Venus, which has been 

 shining so very brightly in the south- 

 west, will attain its greatest brilliance 

 on January 5, when it will shine with 

 no less than one hundred and forty-live 

 times the brightness of a first magni- 

 tude star. It is now drawing continu- 

 ally nearer the sun and consequentlv is 



seen lower in the sky on each succes- 

 sive evening. Yet special effort should 

 be made to observe it for it is at this 

 particular time that it is of greatest 

 interest in the telescope. During Jan- 

 uary it will be seen to change from a 

 planet nearly half full to the narrowest 

 imaginable silvery crescent, and more- 

 over Venus is now so near the earth 

 that a very small telescope will show 

 its change of phase very clearly. 



Venus will pass to the east of the sun 

 on February 9, reaching its greatest 

 brilliance in the morning sky on March 

 16 and its greatest distance from the 

 sun's rays on April 23. On November 

 23 it will again enter our evening hea- 

 vens, but it will not become a conspic- 

 uous object in the west until early in 

 the following year. 



Mars may be called the reigning 

 planet of the coming year, for it will 

 shine brightly in the evening heavens 

 from the very beginning of the year 

 until its close. On January 1 the plan- 

 et is found near the western border of 

 the constellation Virgo and is hence 

 a little beyond the limits of our even- 

 ing map. At this time it is moving 

 slowly eastward (as shown in Figure 

 2) and this eastward motion will con- 

 tinue until February 4. From this lat- 

 ter date until April 26 the planet will 

 move westward until it reaches a point 

 in the constellation Leo. The rapid 

 eastward motion will then be resumed 

 and this will continue until the end of 

 the year. 



Tt is this eastward motion of Mars 

 which will retain it in our evening skies 

 throughout the year. The sun, pur- 

 suing its accustomed path, AVB, Fig- 

 ure 1, will cross the equator at V on 

 March 21, and in due course will over- 

 take and pass to the east of both Jupi- 

 ter and Saturn. By December 31 it 

 will have but a little way passed the 

 Winter Solstice in Sagittarius, while 

 Mars will have moved still farther 

 east into Capricornus. The planet will 

 then be seen glowing redly in the 

 southwest for about two and one-half 

 hours after sunset. 



Jupiter is now in its highest position 

 in our evening heavens. It is seen shin- 

 ing brightly, almost on the meridian, 

 nearly midway between the Hyades 

 and the Pleiades. During the year it 

 will move eastward almost to the cen- 

 ter of the constellation Gemini, bv De- 



