For June, the "Honeymoon", June’s Full Moon, is on June 3rd. The last quarter moon passed below Saturn on June 10th, rising after midnight. The waning crescent sits just to the lower left of Jupiter in the dawn on June 14th. It will be just above Mercury about 40 minutes before sunrise on June 16th. It is new on June 18th.
Back in the evening sky, the waning crescent makes a fine triangle in the west with brilliant Venus to the lower left of it, and much fainter Mars to upper left of both of them. Summer begins with the Summer Solstice at 10:58 on June 21st, the longest day of the year. We get about 14 hours of daylight now. The first quarter moon is June 24.
While the naked eye, dark adapted by several minutes away from any bright lights, is a wonderful instrument to stare up into deep space, far bed our own Milky Way, binoculars are better for spotting specific deep sky objects. For a detailed map of northern hemisphere skies, visit the www.skymaps.com website and download the map for the northern hemisphere skies in June; it will have a more extensive calendar, and list of best objects for the naked eyes, binoculars, and scopes on the back of the map.
There is also a video exploring the June sky from the Hubble Space Telescope website at: www.hubblesite.org/explore_astronomy/tonights_sky. Sky & Telescope has highlights at www.skyandtelescope.com/observing/astronomy-podcasts/ for observing the sky each week of the month.
This June Mercury lies between us and the sun until midmonth, when it moves into the dawn sky just to below the crescent moon on June 16th. Brilliant Venus dominates the dusk for a few more weeks, to pass between us and the Sun in July. It is a greatest eastern elongation, appearing half lit in telescopes, on June 3rd. It seems to be chasing Mars to its upper left, never quite catches up. They are closest, 3.6 degrees apart, at month’s end, but by then, Venus is retrograding back toward the Sun, and now appears only 32% lit crescent. It is now 33" of arc across, and this crescent will be easily observable in hand held binoculars well into July. It is easiest to see this phase in bright twilight, before the planet, now at its brightest, overwhelms the eye’s view.
With our smartphone telescopes scopes we can easily adjust the exposure down to 1/10,000" and catch the phase, and perhaps cloud details, with the new filters and technology. Mars is getting closer to the Sun each evening, and like Venus, will disappear behind the Sun by July. Jupiter and Saturn are both in the dawn sky now, and will not get back for evening observing until this fall.
The Big Dipper is almost overhead as twilight falls, and its pointers take you north to the Pole Star. If you drop south from the bowl of the Big Dipper, Leo the Lion is in the SW. Note the Egyptian Sphinx is based on the shape of this Lion in the sky. Taking the arc in the Dipper’s handle, we "arc" SE to bright orange Arcturus, the brightest star of Spring. Cooler than our yellow Sun, and much poorer in heavy elements, some believe its strange motion reveals it to be an invading star from another smaller galaxy, now colliding with the Milky Way in Sagittarius in the summer sky. Moving almost perpendicular to the plane of our Milky Way, Arcturus was the first star in the sky where its proper motion across the historic sky was noted, by Edmund Halley.
Spike south to Spica, the hot blue star in Virgo, then curve to Corvus the Crow, a four sided grouping. Jupiter lies just east of Spica this July. North of Corvus, in the arms of Virgo, is where our large scopes will show members of the Virgo Supercluster, a swarm of over a thousand galaxies about 50 million light years distant.
To the east, Hercules is well up, with the nice globular cluster M-13 marked on your sky map and visible in binocs. The brightest star of the northern hemisphere, Vega (from Carl Sagan’s novel and movie, "Contact"), rises in the NE as twilight deepens. Twice as hot as our Sun, it appears blue-white, like most bright stars. At the opposite end of the parallelogram of Lyra is M-57, the Ring Nebula. It is visible with large binoculars, but does not show its fine colors and faint central white dwarf until you get to time exposure with a telescope.
Northeast of Lyra is Cygnus, the Swan, flying down the Milky Way. Its bright star Deneb, at the top of the "northern cross" is one of the luminaries of the Galaxy, about 50,000 times more luminous than our Sun and around 3,000 light years distant. Under dark skies, note the "Great Rift", a dark nebula in front of our solar system as we revolve around the core of the Milky Way in the Galactic Year of 250 million of our own years.
To the east, Altair is the third bright star of the summer triangle. It lies in Aquila the Eagle, and is much closer than Deneb; it lies within about 13 light years of our Sun. Use your binocs to pick up many clusters in this rich region of our own Cygnus spiral arm rising now in the east. The nearest spiral arms of our Milky Way are now on the eastern horizon, and may be mistaken for a cloud rising if you are not used to the transparency of rural skies! They arc overhead in the morning hours for restless campers.
To the south, Antares is well up at sunset in Scorpius. It appears reddish (its Greek name means rival of Ares or Mars to the Latins) because it is half as hot as our yellow Sun; it is bright because it is a bloated red supergiant, big enough to swallow up our solar system all the way out to Saturn’s orbit! Scorpius is the brightest constellation in the sky, with 13 stars brighter than the pole star Polaris! Note the fine naked eye clusters M-6 and M-7, just to the left of the Scorpion’s tail.
Just a little east of the Scorpion’s tail is the teapot shape of Sagittarius, which lies toward the center of the Milky Way. From a dark sky site, you can pick out the fine stellar nursery, M-8, the Lagoon Nebula, like a cloud of steam coming out of the teapot’s spout.
