Planets Aplenty! The June Strawberry Moon has Tripped the Scales, and the Treats of Boötes!
The Moon and Planets
The June full moon, known as the “Strawberry Moon”, “Mead Moon”, “Rose Moon”, or “Thunder Moon”, occurs on Friday morning, June 9, so it will look full on both Thursday night and Friday night. This full moon also occurs less than a day after lunar apogee, its maximum distance from Earth, making it the smallest full moon of the year, although you won’t really notice that just by looking at it.
In the meantime, after a Saturday night kiss with Jupiter, tonight’s (Sunday evening) waxing gibbous moon has hopped east to sit about a palm’s width above Spica, the brightest star in Virgo (the Maiden). On Tuesday night, the moon appears below the medium bright star Zubeneschmali, the brightest star in Libra (the Scales). About a palm’s width to the moon’s right, look for the easily split in binoculars double star Zebenelgenubi, which marks the balance point of the scales. By the way, Zubeneschmali marks the north balance arm tip for the scales, while a dimmer star named Brachium (roughly a fist diameter below Zubenelgenubi) marks the southern one.
When the full moon rises in the east at 9 pm local time on Friday, June 9, it will sit only two degrees to the upper left of the ringed planet Saturn. As the Earth’s rotation carries the two objects across the sky during the night, the moon will increase the separation to nearly 4 degrees while also rotating to a position above Saturn before dawn.
All of the classical planets are visible (some with difficulty) this week.
Elusive Mercury continues its tricky morning apparition until late this week. The best time to see the little planet will be just after 5 am local time. By about 5:15 am, the brightening sky will be overwhelming the elusive planet. Look for Mercury in the same location all week — low in the west about one outstretched fist diameter to the south of where the sun will rise. You’ll need a very low horizon free of trees, etc. because, at 5 am, the planet is only two finger widths above the true horizon. Mars is about the same angle away from the Sun, but on the other side, so it’s swimming in the evening twilight above the western horizon.
Extremely bright Venus is at its widest angle west of the Sun this weekend, shining in the pre-dawn eastern sky. Viewed in a telescope around now, the planet will exhibit a half-illuminated phase. It will be in the morning sky for a few more months, becoming easier and easier to view.
Yellowish Saturn rises about 9:15 pm local time this week, and remains visible until it’s hidden by the brightening dawn around 5 am, when it’s 1.5 fist diameters above the southwestern horizon. Next week, Saturn will be at opposition for this year, rising at sunset, and looking its brightest and closest for the year.
Jupiter is the very bright star-like object in the southwestern evening sky, and it sets in the west during the wee hours of the night, local time. Jupiter’s four large Galilean moons are easily visible in a small telescope. A larger telescope will also show the Great Red Spot and the round black shadows cast by Jupiter’s moons when they cross (or transit) the planet. Here are the best events in Eastern Daylight Savings Time. (Simply add or subtract the appropriate hours to convert them to your time zone.)
Starting just after midnight on Saturday evening, June 10, Io’s shadow transits Jupiter from 12:05 am to 2:16 am Sunday morning.
The Great Red Spot is visible on Jupiter for about three hours centred on Sunday, June 4 at 8:50 pm (in twilight), Tuesday, June 6 at 2:38 am and again Tuesday at 10:29 pm, Friday, June 9 at 12:08 am, Sunday June 11 at 1:47 am and again Sunday at 9:38 pm (in twilight).
Finally, the icy giant planets Uranus and Neptune are well-placed for viewing in the pre-dawn sky. Uranus is a few degrees above Venus, and Neptune is in the southeastern sky within Aquarius.
The Treats of Böotes and Coma Berenices
This year, very bright planet Jupiter sits amid the stars of Virgo, and we can use it to guide our way towards an interesting patch of sky that sits immediately above it in early evenings during June — the realm of Böotes (the Herdsman or Plowman) and Coma Berenices (“Berenice’s Hair”).
After it gets dark, face south and look up. About 31° (or three fist diameters held at arm’s length) above Jupiter is a very bright orange-tinted star named Arcturus. The fourth brightest star in the entire night sky, Arcturus means “Guardian of the Bear” in Greek, because it rises after Ursa Major (the Big Bear), which sits to its upper right (west). Arcturus is that colour because it is just passing middle-age for a star, starting on its way towards the red supergiant stage. In Chinese, Arcturus is known as Dà Jiǎo 大角, “Great Horn”.
Arcturus marks the bottom tip of the large kite-shaped constellation Böotes (the Herdsman or Plowman). The rest of the stars in the kite are medium-bright, visible under party light-polluted skies. About 10° above and slightly left (east) of Arcturus are two close-together stars. The higher one named Izar, meaning “Loin Cloth”, is moderately bright. The lower one is much fainter. In a telescope, Izar splits into a gorgeous double star — one is golden and one is white or greenish.
Moving another fist’s width upwards along the same line brings us to the Herdsman’s eastern shoulder, a modest star designated Delta Boötes. It’s a Sun-like star, about ten times the mass of our sun, sitting 117 light-years away. Looking up and to the right about 7.5°, we find a star named Nekkar “Ox Driver”, marking the constellation’s head (or tip of the kite). This is an elderly blue star passing through a phase that is causing it temporarily resemble a large version of our Sun, on its way to becoming a brighter red giant.
Sitting about three degrees away from the line connecting Delta Bootes and Nekkar (shoulder and head) is a triple star named Alkalurops, a name derived from “Shepherd’s Staff”. Two stars can be discerned with good eyes or binoculars, and one of these further divides when viewed in a telescope. All three stars are orbiting in a dance that takes at least 125,000 years for a turn.
As we head from Nekkar back down the crooked western side of the kite, we first stop at a medium bright star named Seginus, which marks the western shoulder. Seginus is also evolving — presently a white giant star that is on the way towards red giant one day. This 85 light-years distant star is spinning about 70 times faster than our Sun!
Moving less than halfway down the constellation towards Arcturus, we find a modest star sitting about four finger widths to the right of Izar. This star, designated Rho Boötes (or ρ Boötis), marks the gentleman’s western hip. There’s a noticeable small start just to its left named Sigma Boötes.
Descending from Arcturus to the east and west are some minor stars that mark the legs and feet. The eastern foot, less than a fist’s diameter to the lower left of Arcturus, is designated Zeta Boötes. In a telescope it is revealed to be a nice matched pair of close together white stars. Moving about four finger widths down the western leg brings us to the bright star Muphrid. It’s also classed like our sun, and actually at the same distance as Arcturus. But its inherent brightness is less, so it looks much dimmer. Dropping down slightly and moving farther right is the star Upsilon Boötes, a very distant red giant star.
The constellation extends way up to the tip of the Big Dipper’s handle. Just before you get there, look for a tight grouping of three stars that represent the herdsman’s upraised hand. The star names are Asellus Primus, Asellus Secundus, and Asellus Tertius “First, second, and Third Donkey”. Two of them are telescopic double stars, but the area around them is a lovely rich field for viewing. And the famous Pinwheel Galaxy (Messier 101) is only a few finger widths above them.
Boötes is in a part of the sky that points away from our Milky Way galaxy, so it isn’t graced with many star clusters and gas clouds. Instead, we see deep into the Universe and the distant galaxies that reside there. For example, while facing south, look about 25 degrees (about equal to your outstretched pinky fingernail to thumbnail separation at arm’s length) to the right of Arcturus. Here lies the dim constellation of Coma Berenices, named for Queen Berenice of Egypt, who sacrificed her hair to Aphrodite in order to protect her husband who was off to war. Binoculars and telescopes sweeping the constellation, and the area just below it, reveal dozens of galaxies. In that area of the sky, astronomers have detected a massive cluster of galaxies several hundred million light-years away. By some estimates there are tens of thousands of galaxies!
Binocular Comet Update
The full moon this week puts a damper on looking for comets. I posted finder charts for the paths of several visible ones during June here. In binoculars and low power telescopes, expect the comets to appear as faint greenish blobs (quite different from a star). If a comet develops a tail, it will point roughly away from the Sun. If you find one in a telescope, watch for 15 minutes or so — you’ll see it moving with respect to the stars nearby.
Comet 41P/Tuttle-Giacobini-Kresak is visible all night, but it’s highest in the sky after midnight. This week, look in the eastern evening sky about midway along the line joining Vega and Saturn.
Comet C/2015 V2 (Johnson) is an all-night binocular comet that is still brightening — visible in the southeastern sky as soon as it’s fully dark. This week, it moves through southern Bootes (the Herdsman), passing less than palm’s width from that constellation’s brightest star, Arcturus today and Monday. Later this week it enters Virgo, heading roughly towards Spica.
Stargazing News for this week (from June 4th) by Chris Vaughan.