Summer arrives this month, and with it, those seemingly endless days. Summer nights, of course are exceedingly short. In fact, Civil Twilight, which is not very dark, ends at 9:50 pm and begins at 4:30 am around the Summer Solstice on June 21st. Summer nights are only about 6 1/2 hours long! Compare this to winter nights, which are about 12 1/2 hours long. If we astronomers could only have both summer weather and winter-length nights at the same time.
The sky map below represents the sky as it will appear in mid-June at the end of astronomical twilight, or the arrival of complete darkness, at about 10pm EDT. The Scope Out monthly focus is on the constellations that are just to either side of the meridian, which is near the 12th hour (12h) of right ascension line in the June sky map. For a primer on how to use this sky map, please read How to begin Observing the Night Sky.
Scope Out divides the celestial sphere into three zones to aid in finding constellations:
3. Southern Constellations: The best-placed constellations in April are Crater, Corvus, and Virgo. Some of these, Crater and Corvus, for example, never rise very far above the horizon because of their deep southern declination.
Mercury begins a morning apparition at the beginning of the month, and it is best observed at its peak western elongation on June 24th. Look for it in the eastern morning sky about 45 minutes before sunrise. Mars in now hidden in the sun’s glare and will not be visible until it emerges as a morning object later this summer. Venus is the very bright object in the western sky after sunset. It is near its peek elongation from the Sun, and telescopically presents an appearance similar to a crescent moon. The crescent will become thinner, and the planet’s disk will appear to grow larger through the remainder of its evening apparition. Jupiter is the bright object that appears nearly overhead at nightfall. Read about its coming conjunction with Venus below. Saturn is just past opposition, and can be found above the eastern horizon at sunset. It remains showy both visually and telescopically. Uranus and Neptune are morning objects that rise just before dawn.
THE LUNAR CALENDAR
Conjunction with Venus
Conjunction with Jupiter
Conjunction with Saturn
Summer Solstice – June 21
Summer officially begins when the sun reaches its northernmost point on the celestial sphere at 12:38pm on June 21st. At local noon, when the sun reaches the meridian, it will be at its highest point in the sky for observers north of the Tropic of Cancer. The longest day of the year and the shortest night of the year occur within a few days of this date.
Conjunction of Venus and Jupiter – June 30
Venus and Jupiter have been visible together in the evening sky since March, with Venus on the western horizon and Jupiter on the eastern horizon. These two planets have been slowly approaching one another these past few months, and will finally meet at month’s end. They begin the month about 20° (about a hand’s length) apart. Venus will be near Gemini’s two brightest stars, Castor and Pollux, and these three objects will appear in a nearly straight line on June 1st. Jupiter will be to their east. The moon will move through this area just after mid-month, passing Venus on the 19th, and Jupiter on the 20th. The two planets will reach conjunction on June 30th, appearing just 1/3° apart, which is the same field of view of most telescopes.
© James R. Johnson, 2015