All five naked-eye planets are visible in June, though we have a narrow window to see Mercury early in the month.
The moon has lovely gatherings with the planets at several times in June. Summer returns to the northern hemisphere, and June provides the final chance each year to see the Southern Cross from the islands.
Mercury is barely visible at dusk low in the west in the first couple of days of June. If you want to seek it, look west at 8 p.m. as darkness settles in. Mercury is a mere 4 degrees above the horizon (two fingers at arm’s length) and it is already down to a faint 1.46 magnitude. The foot of Castor, the Gemini twin, points to it. Mercury sets by 8:30 p.m. on June 1; by June 5, it is lost in the light of the sun.
Jupiter has been with us all winter and spring as the brightest dot of light in the evening sky, blazing away at minus-2 magnitude; but its days are numbered. In fact, June is pretty much the month we lose it. Jupiter will pop out nicely at the start of the month, shining about a third of the way up in the west at dusk and setting just before 10 p.m. in the west.
Every night the king of the planets will appear a little lower in the west at first darkness. By the end of June, Jupiter is so low in the west that it barely appears before it sets at 8:15 p.m.
On June 1, look for the crescent moon just to the upper left of Jupiter, from first darkness until the moon and Jupiter set around 10 p.m.
In early June, look for Mars about two-thirds of the way up in the south at first darkness, still shining brightly (and orangely) at magnitude minus 0.5. Mars sets around 2:30 a.m. in early June and will drop to zero magnitude by the end of the month, but it will still pop out nicely with its distinctive orange color.
By June 30, look for Mars about halfway up in the west at dusk, sliding down the western sky throughout the evening, and setting around 1 a.m. Look for the bluish-white star Spica to the left of Mars all month; Spica is several times dimmer than Mars. Also look for the waxing gibbous moon close to Mars on June 7.
In early June, look for Saturn at dusk about halfway up the sky in the southeast; by month’s end, it’s due south at nightfall. It shines a 0.3 magnitude all month. Saturn sets in the west at 4:30 a.m. in early June, and 2:30 a.m. in late June.
Lacking the brilliance of Jupiter and Venus, and the distinctive orange color of Mars, Saturn does not "pop" like those other planets. As our June map shows, Saturn is right in front of the claws of Scorpius, a good guide to finding Saturn. Also, on the nights of June 9 and 10, the nearly full moon will appear close to Saturn, an even easier way to find the planet.
Venus remains a constant in the morning sky, rising in the east just before 4 a.m. all month and shining brilliantly at minus-4 magnitude. It is so bright that it should remain visible until about 30 minutes before sunrise. On the morning of June 24, look for Venus above the waning crescent moon.
LAHAINA NOON
Since the June Skywatch runs in the Honolulu Star-Advertiser on the last Sunday in May, you may read these words in time to catch Lahaina Noon, which occurs at 12:28 p.m. on Memorial Day in Honolulu.
In the tropics, the sun passes overhead twice during the year. On these two days, at local noon, the sun will be exactly overhead and an upright object, such as a flagpole, will have no shadow. Lahaina Noon only occurs in the tropics; the sun is never overhead in any other part of the planet.
Your dates for overhead noon depend on how far north or south you are in the tropics.
The farther north you are, the later your first Lahaina Noon day will occur. So the first Lahaina Noon in May happened on May 18 in Hilo and Kailua-Kona, at the south end of our island chain. And it has already happened in Lahaina (12:23 p.m. on Saturday) and in Lanai City (Saturday, 12:24 p.m.)
Lahaina Noon occurs Sunday in Kaunakakai (12:24 p.m.), Tuesday in Kaneohe (12:28 p.m.) and Saturday (12:35 p.m.) in Lihue.
STARS IN JUNE
June is the last chance each year to see the Southern Cross, officially called Crux, from the Hawaiian islands. The bright stars Alpha and Beta Centauri, to the left of the cross, can serve as a pointer to the more-elusive cross.
At the start of the month, Crux is due south at dusk, and sets around 11 p.m. By the end of June, Crux is already heading for the western horizon at dusk, and sets by 9 p.m. Our star map, good for 11 p.m. at the start of June and 9 p.m. at the end, shows the cross as it sets.
Also in the south, look for Scorpius rising high. To its left, Sagittarius the archer has returned to our sky.
In the center of the sky, the bright star Spica is right in between Mars and Saturn, while Arcturus, known in the islands as Hokule‘a, shines above them.
In the north, look for the Big and Little Dippers, with Draco winding its way between the two dippers.
In the west, the classic spring constellation of Leo the Lion heads for the horizon; while that classic summer sight, the Summer Triangle, rises in the east.
Mike Shanahan is the director of visitor experience and planetarium at Bishop Museum. For more information, go to www.bishopmuseum.org/planetarium/planetarium.html.