Abstract
ON July 1, the duration of night (sunset to sunrise) in the latitude of London is 7·5 hours; astronomical twilight (the sun not greater than 18° below the horizon) lasts all night until July 21. The moon is new on July 5 and full on July 19. The moon is in conjunction with Mars on July 6, with Jupiter and Saturn on July 28 and with Venus on July 31. From the western parts of North America, Venus will be seen to be occulted by the moon at this conjunction in daylight. There is no bright planet conspicuous now in the evening skies, since Mars-the remaining member of the notable group of bright planets seen in the evenings of the early part of this year-is getting too close to the sun for observation. At the beginning of the month, Jupiter and Saturn rise within a quarter of an hour of each other not long after midnight (U.T.). Venus is the bright morning star seen about one hour before sunrise in the middle of July and 2 J hours before sunrise at the end of the month. The planet is increasing in brightness towards its maximum on August 2. Close groupings of Jupiter's four inner satellites (to be seen with binoculars) occur about 2h. on July 2, 12, 20, and 21. The ring system of Saturn is well open, the minor axis of the outer ellipse of the outer ring being greater than 13”. The delta Aquarid meteors reach a maximum frequency about July 28.
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The Night Sky in July. Nature 145, 1015 (1940). https://doi.org/10.1038/1451015b0
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DOI: https://doi.org/10.1038/1451015b0