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THE GUIDE TO NATURE 



thought by most people, two or three 

 evenings' observation is all that is re- 

 quired, and this pleasurable study 

 (aside from being most interesting and 

 profitable in itself) is a most wise and 



Figure 3. AppearRiice of the planet Venus when 

 nearly between tVie F.arth and Sun. The great pro- 

 longation of the horns and the very irregular ter- 

 mination show clearly that Venus has a danse atmos- 

 phere. The dim lig'ht on the ball of the planet is 

 probably of an auroral nature. 



preliminary preparation for a more de- 

 tailed exploration of the heavens with 

 a small telescope. 



The Planets in May. 



Mercury enters the evening sky on 

 May 3, and on May 12 it reaches its 

 greatest distance east of the sun. For 

 a few days before and after this date 

 it may easily be detected shining in 

 the twilight glow for nearly two hours 

 after sunset. It should be looked for 

 in the northwest only a short distance 

 above a point of the horizon which is a 

 little farther toward the north than the 

 point at which the sun was seen to set. 



In the telescope it will be seen to be 

 a beautiful little brightly shining world, 

 its shape the same as that of the moon 

 when half full. Having found it while 

 it is in this most favorable position, 

 the observer can follow it for several 

 days and see it rapidly changing into 

 a narrow crescent as it draws nearer 

 the sun's rays. It will finally withdraw 

 from the evening sky on June 3. . 



Venus is by far the brightest and 

 most striking object now in the 

 heavens. No one who turns toward 

 the western sky in the early evening 

 can fail to have his attention arrested 

 by this exceedingly brilliant evening 

 star. On May i, it will be seen to oc- 

 cupy the position H, Figure i, a little 



to the east of the horns on the Bull, but 

 as the weeks go by it will move rapidly 

 eastward, almost crossing Gemini, un- 

 til by May 31 it will attain the position 

 K. This eastward motion, in which 

 the planet has continued for so many 

 months, will, however, soon cease. On 

 June II the planet will reach the posi- 

 tion M, and will then begin to run 

 rapidly toward the west. It will finally 

 pass to the right of the sun and leave 

 the evening sky on July 3. 



At present the planet is wonderfully 

 brilliant and so high in the heavens 

 that it sets far in the northwest so late 

 as seven hours after sunset. It attains 

 its greatest brilliance on May 27, at 

 which time it will shine with no less 

 than one hundred and twenty times 

 the brightness of a first magnitude star. 



No observer who possesses a small 

 telescope should fail to study Venus 

 from time to time during the present 

 month. He will see its shape change 

 rapidly to that of a narrow crescent, 

 as more and more of the right side of 

 the planet is turned toward us, and he 

 may even at times detect the faint il- 

 luminations sometimes seen on this 

 darkened hemisphere and which are 

 probably caused by auroras in the night 

 skies of our Sister World. He will al- 

 so see that the line of division between 

 the dark and the sunlit part of the 

 planet is by no means a sharp line, but 

 that it fades gradually in some places 

 and is irregular in others. This is the 

 twilight on Venus, and tells us clearly 

 that this world is surrounded by a 

 heavy atmosphere. 



Venus in its eastward motion will 

 pass Saturn on the forenoon of May 

 24 ; it will again pass Saturn — this time 

 during its westward motion — on June 

 22. The approach of the two planets 

 will be much closer at the latter con- 

 junction than at the former one. 



Mars is moving eastward into Leo 

 and is still a conspicuous object in 

 the heavens, though its distance away 

 is now so great that it is not a very 

 satisfactory object in the telescope. 



Jupiter is in the morning sky, rising 

 I hr. 10 min. before the sun on May i, 

 and 2 hrs. 30 min. before sunrise on 

 May 31. It has not yet, however, suf- 

 ficiently emerged from the sun's rays 

 to be in very favorable position for ob- 

 servation. 



Saturn is near the middle of the con- 

 stellation Gemini, sufficiently high 



