ASTRONOMICAL NOTES FOR SEPTEMBER, 1883. 30S. 
light we receive at its maximum brilliancy equals that of a first magnitude star, 
but being always seen when near the horizon, it does not appear brighter than 
one of the second magnitude. During this month its south declination is rapidly 
increasing, also the apparent diameter. On the 24th it is moving in a direct line 
toward the earth. 
Venus. — This planet cannot be seen this month except by the aid of a good 
telescope. On the 20th at 5 o'clock P. M., she is in superior conjunction with 
the Sun and will pass very close to his northern limb ; were it possible to measure 
the distance it would equal two-thirds of the apparent diameter of our Moon. 
Mars. — This will be in right ascension 6 h. 23 min. to 7 h. 37 min., and 
will rise, in the morning about i o'clock, at a point 23° north of east. Its diame- 
ter is 6.2" on the ist and slowly increases. On the morning of the 20th it is in 
conjunction with Delta Geminorum and will pass 49' north of the star. The 
Moon also pays him a visit on the 24th. He is too far from the earth for telescopic 
study ; with the best instruments his satelhtes cannot be seen. 
Jupiter. — The giant planet of our system is rapidly gaining a conspicuous 
position as morning star, rising about four hours before the Sun. On the ist it 
is in the western edge of the constellation Cancer and will remain in this constel- 
lation during the entire month. Its apparent right ascension is 7 h. 50 min. to 
8 h. II min., decUnation north 21° and slowly decreasing. This massive planet 
is about 13,000 times larger than the earth. His mean distance from the Sun is 
480,000,000 of miles; length of his year, or time of revolution round the Sun, is 
fifty days less than twelve years. It can be easily recognized by his brilliant 
white light, with which he outshines every other planet or star in the eastern sky, 
except the Sun and Moon. There is no other object in our system that has been 
the subject of more careful examination than this same planet. There are no 
really permanent markings on his disk, therefore a map of Jupiter is impossible ; 
but his surface always presents a very diversified appearance. The first telescopic 
observers described light and dark belts as extending across it; until quite recently, 
it has been customary to describe these belts as two in number, one north of the 
Equator, and one south of it; usually they are seen as dark bands on the bright 
disk of the planet. Huyghens represents them as brighter than the rest of the 
disk. As telescopic power increased, it was found that the so-called bands were 
of a far more complex structure than supposed, and presented more of a cloud- 
like form; these forms change so rapidly that the face of the planet hardly ever 
presents the same appearance on two successive nights. In addition to the ever- 
changing features of the disk, it is also attended by four moons, which as they 
course round the planet in their orbits, lend additional interest to the picturesque 
phenomena presented by this miniature representative of our system. As the 
plane of the orbits of the moons lie in the same direction with the Equator, they 
must, at every round they make in their orbits, get eclipsed by entering the 
shadow of Jupiter, occultated by passing behind the planet and appear as light 
and dark spots on its face when they are between the Earth and its disk, also the 
Sun when they make eclipses the same as our Moon does on the Earth. The 
