i5o 



THE GUIDE TO NATURE 



terns of four bright moons in rapid mo- 

 tion about the planet and its own rapid 

 rotation, which carries its ever-chang- 

 ing markings rapidly across the disc, 

 all furnish, perhaps, the most beautiful 

 and interesting of all objects suitable 

 for observation with a small telescope. 

 During the present month there will 

 be a large number of interesting 

 eclipses, occultations and transits of 

 Jupiter's moons. For example, on 

 September 3 at 7.55 P. M. (Eastern 

 Standard time) the inner moon will 



year journey around the heavens, it has 

 moved entirely out of Taurus and into 

 Gemini. It is far to the east of the 

 Horns of the Bull, and will be found 

 near the stars Mu and Eta of the 

 Twins. Its rings are at present well 

 widened out, and it is an interesting 

 telescopic object. 



Neptune is also in Gemini, and so is 

 a morning star. 



Uranus is a short distance to the 

 west of Jupiter in the constellation 

 Capricornus, but this world is a disap- 



Figure 2. Recent drawings of the planet Jupiter. The second was made one hour after the first, and shows'the- 

 change in appearance caused by the turning of the planet and by the real changes which constantly take'place.upom 

 its surface. 



pass behind the planet's disc, and at 

 10.50 it will emerge from eclipse. On 

 the next evening at 7.23 it will enter 

 upon the disc, and on this same night 

 at 1.40 A. M. the outer moon will dis- 

 appear behind the planet. Two moons 

 only will then be visible in the tele- 

 scope. On the evening of September 

 12 the inner moon will emerge from 

 eclipse at 7.13 P. M., and the third 

 moon pass behind the planet at 2.04 the 

 next morning. Similarly, on the 17th 

 at 11.28 P. M. the first moon will pass 

 behind the planet, and on the next 

 evening at 8.35 the first moon will pass 

 in front of the planet, leaving the disc 

 at 11.56. Eclipses, which are so rare on 

 the earth, are very common phenomena 

 on the planet Jupiter. 



Saturn has not yet quite entered our 

 evening heavens, though it is but little 

 below the eastern horizon and is a con- 

 spicuous object a little after midnight. 

 The reader may remember how this 

 world a few months ago shone out 

 brightly in the constellation Taurus, 

 between the Hyades and the Pleiades. 

 Now, in the course of its twenty-nine- 



pointing object for study except in the 

 largest telescopes. 



The New Comet. 



The comet discovered a few months 

 ago has now passed around the sun, 

 and during the present month will 

 move through the length of the Greater 

 Bear, directly below the Great Dipper. 

 Up to the present time this has been a 

 bright and interesting object when! 

 viewed in a large telescope, but it can- 

 not yet be said whether or not it will 

 become a conspicuous object to the 

 naked eye. Undoubtedly, it will reach 

 its greatest brightness during the pres- 

 ent month. It will be nearest the 

 earth on October 2, but even at this 

 time it will be no less than 144 mil- 

 lions of miles away. Yet it is certain 

 that this is a comet of very unusually 

 great size and brightness, and it is 

 hoped that it may, therefore, become a 

 naked-eye object. Its path during .Sep- 

 tember is shown in Figure I. 



The Eclipse of the Moon. 



On September 4 at 7.16 A. M. (East- 

 ern Standard time) the full moon will 

 pass into the earth's shadow and enter 



. 



