A Table showing the Illuminated Portions of the Discs of Venus and Mars. The numbers in this table are the versed sines of that portion of the Discs, which, to an observer on the Earth, will appear to be illuminated, the apparent diameter of the planet at the time being considered as unity. To a spectator on the Earth, Venus appears most brilliant when her elongation is about 45°, and she is approaching her inferior conjunction, or receding from it; in which positions she will be this year on the 27th of August, and the 8th of November. Mars is most brilliant about the time of his opposition to the Sun, being then also nearest to the Earth, in which position he will be this year on the 31st of October. Position and Magnitude of the Rings of Saturn, according to Bessel and Struve for every fortieth day in the year, at 7 hours in the morning. 66 66 semi-conjugate axis of the rings, positive when their northern surface is visible, negative when their southern. inclination of the northern semi-conjugate axis of the rings to angle of elevation of the Sun above the plane of the rings, as The Opposition will take place on the 2nd of September. |