Astronomical Notes.
Reading edition
OBSERVATORY OF VASSAR COLLEGE.
The computations in the following notes are by students of Vassar College. Although merely approximate, they are sufficiently accurate to enable the ordinary observer to find the planets.
M. M.
POSITIONS OF PLANETS FOR JULY, 1880.
Mercury.
On July 1 Mercury sets a few minutes after 9 in the evening.
Mercury can be readily found, early in July, a few degrees south of the point of sunset; the planet moves rapidly southward, but can be followed, and may be seen as late as the 20th. On July 18 Mercury has nearly the declination of Regulus.
Venus.
Venus keeps nearly the path of the sun, setting after the sun late in July, but so nearly with it that the planet is not likely to be seen.
Mars.
Mars has moved from its position nearly in line with Castor and Pollux toward Leo. It sets on July 1 at 9h. 44m. P.M. On the 31st Mars sets at 8h. 32m.
On the 31st, at meridian passage, Mars and Uranus are nearly together. Uranus is east of Mars and half a degree south.
Jupiter.
Jupiter is coming into the evening hours.
On July 1 Jupiter rises a few minutes after midnight. On July 31 Jupiter rises a few minutes after 10 P.M. It will be known at once by its brilliancy.
Besides the ordinary belts of Jupiter the planet still shows at this time (June 10) the large ruddy spot spoken of by many persons some weeks since. This spot is elliptical in shape; its longest diameter is about one-fifth that of Jupiter. A small glass will show it, and the ordinary observer can, by watching its appearance and disappearance and reappearance, determine the time of rotation of Jupiter on its axis, or the length of the planet's day.
The best evenings for looking at Jupiter are those of July 23, when the satellite nearest to Jupiter goes across its face, preceded by its shadow; July 28, when the first and second satellites will make similar transits; and July 29, when Jupiter will rise without the presence of its third satellite, which will be in eclipse, and will come out of the shadow after midnight.
Saturn.
Saturn follows close upon Jupiter, but keeps further north in declination by about 2½°.
On July 1 Saturn rises 36m. after midnight. On the 31st Saturn rises at 10h. 38m. P.M.
The waning moon will pass north of Jupiter and Saturn on the 27th to 28th.
Any one who has a glass sufficient to show the ring of Saturn and the largest satellite, Titan, will find this planet intensely interesting, and the movements of the satellite will show the time of its revolution in its orbit around Saturn.
Uranus.
Uranus rises after the sun, and sets too nearly with the sun to be seen.
Neptune.
Neptune may be seen, with a good telescope, in the early morning hour. Neptune is 2¼° west of Alpha Ceti, and 11° north. It approaches Alpha Ceti during the month, and if it can be found, may be known to be a planet by that movement.
