The springtime constellations are well-placed in June’s evening skies, but begin to give way to the summer constellations that follow. Scorpius is the first summer constellation to rise, its head popping up above the ESE horizon at sunset in early June. Venus emerges from the twilight into darker evening skies, lighting up the WNW. Summer solstice occurs on June 20th, the Sun appearing above the Tropic of Cancer on that date. After the solstice, the Sun begins its six month trek south. On June 24th, we’re treated to a full supermoon.

June Planets:

At the beginning of the month, Mercury is still an evening object, albeit a difficult one, requiring binoculars to see as it moves back toward the Sun. Our innermost and fastest planet passes the Sun and becomes a morning object in late June, gracing the constellation Taurus.

Bright Venus and dimming Mercury (slightly below and to the left of Venus) made a close pair in the sunset sky on May 28th.

Venus starts June above Mercury, in Gemini. The brightest object in the evening sky, our ‘sister planet’ moves higher above the WNW horizon all month, ending June near Mars, in Cancer.

Mars continues to fade in the WNW as it recedes from Earth, moving from Gemini into Cancer. At the end of June, the Red Planet sets about 10:20pm MDT, just after twilight ends.

Saturn starts June as a morning object, rising in Capricornus about 12:25am MDT. At the end of June, Saturn is an evening object, rising in the ESE about ten minutes after Mars sets on the opposite side of the sky.

About an hour after Saturn rises, Jupiter chases Saturn into the ESE. Our solar system’s largest planet, Jupiter, in Aquarius, moves from the morning to the evening sky during June, by far the brightest object in the neighboring fall constellations.

Jupiter (left) and Saturn (2 o’clock from Jupiter, just above the cloud) rise to the east of the Milky Way in late April.

June Spotlight:

The constellation Scorpius, the scorpion, is the first of the summer zodiac constellations to appear in June’s skies. In Indonesia, the constellation is known as ‘kalapa doyong’ (‘the leaning coconut tree’). Ancient Hawaiians called the constellation ‘Ka Makau Nui o Maui’ (‘the Big Fishhook of Maui’), Maui being a Polynesian demi-god. In Navajo mythology, the stars of Scorpius form ‘Altse Etsoh,’ the ‘First Great One’. The star we call Antares marks the heart of Altse Etsoh.

Our constellation maps tend to follow Greek and Roman mythology. Located in the heart of the scorpion, the brightest star in Scorpius is Antares, ‘the rival of Ares,’ Ares being the Greek equivalent of the Roman god of war, Mars. The name is due to Antares’ similarity to the planet Mars, in terms of color and brightness. Because Antares is located near the ecliptic (the invisible path that the Sun and planets follow, as seen from Earth), every few years, Mars passes close to its anti-namesake, allowing us to easily see their similarity.

The core of the Milky Way runs through the constellation Scorpius, seen right of center. Antares is the bright red star above and right of center. You can see the dark dust clouds of the Rho Ophiuchi Cloud Complex, just above Antares.

On June 3rd, Antares is at opposition to the Sun, rising in the ESE at the same time the Sun sets in the WNW. Because of this, the star is visible from twilight to dawn during the month of June.

Antares is a red supergiant star, its diameter is 700 times that of our Sun. Earth would not exist in the Antares solar system since the star is so massive, Earth’s orbit would be well inside the star. In fact, the star is wider than the orbit of Mars, so Mars wouldn’t exist, either – I guess the anti-Mars wins…

Antares is a variable star, its brightness fluctuating between magnitudes 0.6 and 1.6. It’s also a binary star, meaning that it has a companion star, the two stars revolving around a common center of gravity. The companion star is called Antares B. It’s blue-white, a marvelous contrast to Antares’ red, and at magnitude 5.5, is much dimmer than the primary star.

Antares appears to sit within the Rho Ophiuchi Cloud Complex, an area of dust and gas that gives birth to stars. About 425 light years distant, the Cloud Complex is one of the closest stellar nurseries to our solar system. Antares is 550 light years away, so while it appears to be part of the Rho Ophiuchi Cloud Complex, it’s actually well behind and shining through it, as seen from Earth.

The Rho Ophiuchi Cloud Complex. Antares is the bright star below and left of center. The globular cluster Messier 4 is to the right of Antares. A second, smaller globular cluster, NGC 6144, can be seen above and to the right of Antares.

Photo credit: Adam Block, Steward Observatory, University of Arizona.

June Night Sky Events:

June 10: New moon.

June 11: A thin crescent moon and Venus make a close pair in the evening twilight.

June 13: The Moon passes Mars in Cancer.

June 20: Summer solstice occurs at 9:21pm MDT when the Sun is at its northernmost position in the sky, as viewed from the northern hemisphere.

June 24: A full supermoon occurs at 12:40pm MDT. The Navajo people call a full moon, ‘haniibaaz.’

May’s full supermoon rises before the sun sets, giving it an indistinct appearance until the sky darkens.