As we move into high summer, the sun turns southwards, our nights begin to lengthen and the moonless spell later in the month brings many of us our first dark skies of the summer.
The Plough is in the north west as the Summer Triangle reaches the high meridian. Formed by the bright stars Vega, Altair and Deneb, in the constellations Lyra, Aquila and Cygnus respectively, it is bisected by the Milky Way, which arches high across our eastern sky from Sagittarius and Scorpius low in the south to Cepheus, Cassiopeia and Perseus in the north east.
Many of the stars in an area of sky between Deneb and Vega were scanned by the Kepler space telescope in its primary search for extrasolar planets. Its latest catalogue lists 4,034 possible planets, including 50 Earth-sized ones which orbit within their habitable zones.
The one really bright planet visible this July map times is Saturn, still edging westwards following its opposition in Ophiuchus. Although it dims slightly from magnitude +0.1 to +0.3, as the month progresses it remains the brightest object low in the southern sky until it sets in the south west about 3am.
The moon is above and to the right of Saturn on the 6th when telescopes show the Saturnian disc to be 18 arcsec wide, while the rings span 41 arcsec and are tipped wide open at 26.7° in our favour. Even binoculars are enough to show that Saturn is more than just a circular dot.
Jupiter, conspicuous at magnitude -2.0 and now moving eastwards to the right of Spica in Virgo. Look in the lower south western sky at nightfall, where it is near the Moon on the 1st of the month. The Moon is near again on the 28th, but by then Jupiter is lower still in the west, south west as it sinks to set in the west around midnight.
Venus improves as a brilliant morning star of magnitude -4.1 to -4.0. Rising in the north east at about three hours before the sun. It reaches 19° high in the east at sunrise on the 1st of July and 6° higher by the 31st. It lies 8° below-right of the Pleiades in Taurus on the 1st and slides between the Pleiades and Aldebaran to pass 3° above left of the star on the 14th. Telescopically, its diameter shrinks from 18 to 15 arcsec and its sunlit phase grows from 63% to 74%.
Around the 28th and 29th of this month we will see the annual peak of the Delta Aquarid meteor shower. It might be possible to see up to 20 meteors per hour. The best time to see this shower will be between midnight and dawn. Delta Aquarid meteors may come from Comet Machholz which was discovered by Donald Machholz in 1986.
Phases of the Moon for July
First Quarter 1st
Full Moon 9th
Last Quarter 16th
New Moon 23rd
First quarter 30th