The Mirror of Literature, Amusement, and Instruction - Volume 10, No. 262, July 7, 1827 by Various
page 30 of 50 (60%)
page 30 of 50 (60%)
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stationary on the 29th.
There is only one visible eclipse of Jupiter's first satellite this month--on the 5th, at 10h. 21m. evening. The Georgium Sidus, or Herschel, comes to an opposition with the sun on the 19th, at 6h. 15m. evening; he is then nearest the earth, and consequently in the most favourable position for observation; he began retrograding on the 1st of May in 28 deg. 12m. of _Capricornus_; he rises on the 1st, at 9h. 11m. evening, culminating at 1h. 16m., and setting at 5h. 21m. morning, pursuing the course of the sun on the 17th of January; he moves only 13m. of a deg. in the course of the month, rising 2 h. earlier on the 31st. This planet, called also Uranus, was discovered by Herschel on the 13th of March, 1781. It is the most distant orb in our system yet known. From certain inequalities on the motion of Jupiter and Saturn, the existence of a planet of considerable size beyond the orbit of either had been before suspected; its apparent magnitude, as seen from the earth, is about 3-1/2 sec., or of the size of a star of the sixth magnitude, and as from its distance from the sun, it shines but with a pale light, it cannot often be distinguished with the naked eye. Its diameter is about 4-1/2 times that of the earth, and completes its revolution in something less than 83-1/2 years. The want of light in this planet, on account of its great distance from the sun, is supplied by six moons, which revolve round their primary in different periods. There is a remarkable peculiarity attached to their orbits, which are nearly perpendicular to the plane of the ecliptic, and they revolve in them in a direction contrary to the order of the signs. |
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