Astronomical Phenomena during July

Abstract

VENUS is a conspicuous object in the evening sky. The planet reaches its greatest eastern elongation on June 30, when the stellar magnitude is 4·0m, but the planet will continue to increase in brilliance throughout July, the stellar magnitude being 4·2m on July 31. As both Mars and Jupiter are conspicuous in the evening sky, one can get a very good idea of the ecliptic stretching across the sky, especially when the moon is visible. Mars, the magnitude of which is +0·3m at the beginning of July, will decline in brightness by three tenths of a magnitude during the month. The planet will move towards Jupiter, which is near a Librae. Jupiter's magnitudes are l·9m and 1·7m at the beginning and end of the month respectively. Saturn's Right Ascension is 22h 49m, about eight hours behind Jupiter and 11h 36m behind Venus at the end of the month. Saturn's declination being 9 ° S., it will not be possible to see these four of the five naked eye planets in the same sky from stations north of terrestrial latitude 40 ° N. during July. Venus is in conjunction with Neptune on July 25 at 06h G.M.T., Venus being 2·6 ° S. There is a partial eclipse of the sun, partly visible at Greenwich, on June 30. The eclipse begins at 20h 07m G.M.T. and fourteen per cent of the disc will be covered at sunset. A total eclipse of the moon on July 16 is also partly visible at Greenwich. The moon enters the penumbra on July 16 at 02h 15m and leaves the penumbra on July 16 at 07h 43m, the eclipse being visible on the Atlantic Ocean generally. A further partial eclipse of the sun takes place on July 30; this will be invisible at Greenwich.