Our Astronomical Column

Abstract

WINNECKE'S COMET.—In No. 2,314 of the Astronomische Nachrichten Prof. v. Oppolzer has a note of more than ordinary interest on the motion of this body as investigated by his own calculations. He states that it results from his computation of the perturbations with the object of connecting the three appearances of 1858, 1869, and 1875 that a satisfactory agreement cannot be found without one of two hypotheses; either the mass of Jupiter must be diminished to 1/1051, or there is a necessity of admitting the existence of a similar extraordinary influence upon the motion of this comet to that first pointed out by Encke in the motion of the comet which bears his name. Prof. Oppolzer finds an acceleration in the mean daily sidereal motion of 0″.01439 after one revolution, a result which, he remarks, is in close accordance with his earlier one, deduced by a provisional calculation of the perturbations, from the observations made at the comet'S appearance in the summer of 1819. He infers from his researcheS upon Winnecke's comet a value for Encke's force designated by U, differing little from that assigned by Encke from his discussion of the motion of his comet, the more satisfactory considering that much latitude must be allowed in this direction. He further observes that with U = 1/900 the effect upon the motion of Faye's comet would be so small that it is necessarily mixed up with uncertainty in the values of the perturbations; it will be remembered that Prof. Axel-Möller, who has laboured so admirably to follow up with every precision the motion of Faye's comet, has not, since his computations assumed their present refined form, been able to detect any abnormal effect upon it.