Venus and Jupiter drift apart, blue moon appears later in July
Having just completed their close conjunction on the last evening of June, Venus and Jupiter are now slowly drawing apart from one another in the evening sky. Shortly after sunset, the two planets are visible half way up the western sky. Venus (mag. - 4.6) sits to the left of Jupiter (mag. - 1.8), and slowly drifts further to the SW away from Jupiter as the month progresses.
At mid-month, Venus has brightened slightly to mag. - 4.7, its peak brightness for this evening apparition. As July opens, the two planets are paired for about two hours before dropping below the western horizon. By the end of the month, Venus will follow the sun down about 30 minutes afterward, with Jupiter setting a half hour later.
To the upper left of Venus sits Regulus, the brightest star in the constellation of Leo the Lion. Regulus is the “dot” star in the reversed question mark asterism that forms the head and shoulders of the lion. Venus, Jupiter and Regulus form a constantly changing triangle configuration throughout the month. On the evening of the 18th, the slender, crescent moon joins the picture, making for a great photo opportunity. By the end of the month, about one hour after sunset, both planets are lost from sight in the evening twilight.
Saturn is the next naked-eye planet to become visible, appearing about 30 degrees above the southern horizon as darkness falls. By mid-month, Saturn shines at + 0.3 mag., easily the brightest object in that area of the sky. On the night of July 2526, the waxing, gibbous moon sits just to the north (upper right) of Saturn. Though it will be hard to distinguish with the naked eye, Saturn dims slightly as July progresses, dropping from mag. + 0.2 to + 0.4. Saturn’s majestic rings are tilted at 24 degrees to our line of sight in July.
Mercury shines brightly in the morning twilight during the first two weeks of July. About a half hour before sunrise, Mercury can be spotted about eight degrees above the ENE horizon. By the third week of July, Mercury drops deep into the gathering twilight, until on July 23 it slips behind the sun (superior conjunction) and is lost from sight altogether.
The only meteor shower of note this month is the Southern Delta Aquariids (radiant in Aquarius - the water bearer). Active from around July 12 to the 23rd of August, this shower’s peak will come during the predawn hours of July 30. Unfortunately, this is only one day before the blue moon - the second full moon of July, on the 31st, so the light from the near-full moon will reduce the number of meteors seen during the peak (normally 15-20/hr).
The first full moon was on July 1. However, getting out on the mornings of July 27-29 will provide a brief window of opportunity between moon set and the start of morning twilight, during which time you might see as many as 12-15 meteors/hr.
As mentioned above, July has two full moons - July 1 and 31. The second full moon occurring in any given month is referred to as a blue moon. This is not to be confused with when the moon takes on a bluish colour due to dust particles in the upper atmosphere. July’s blue moon is the first since August 2012.
Until next month, clear skies.