Night sky guide for June 2016

On June 3, planet Saturn will be at its closest approach to Earth and its face will be fully illuminated by the Sun. It will be brighter than any other time of the year and visible all night long. 

The best time of the month to observe faint objects such as galaxies and star clusters because there is no moonlight to interfere - New Moon - is on June 5. On the same day, planet Mercury will be well placed for observation across much of the world, shining brightly at mag -1.9.

The Ophiuchid meteor shower will reach its maximum rate of activity on June 20, 2016, but some shooting stars associated with the shower are expected to be visible each night from May 19 to July. The maximum rate of meteors expected to be visible from a dark location is around 5 per hour (ZHR). However, the Full Moon will severely limit the observations that will be possible.

On the same day, at 22:34 UTC, the North Pole of the Earth will be tilted toward the Sun, which will have reached its northernmost position in the sky and will be directly over the Tropic of Cancer at 23.44 degrees north latitude. This is the first day of summer (summer solstice) in the northern hemisphere and the first day of winter (winter solstice) in the southern hemisphere - June Solstice.

• June 1 - Conjunction between the Moon and Uranus - 15:27 UTC. The Moon and Uranus will make a close approach, passing within 2°18' of each other. At the moment of closest approach, the Moon will be at mag -10.8, and Uranus at mag 5.9, both in the constellation Pisces. The pair will be too widely separated to fit within the field of view of a telescope, but will be visible to the naked eye or through a pair of binoculars.

• June 1 - M13 well placed for observation. The Hercules globular cluster (M13, NGC 6205) will be well placed for observation. It will reach its highest point in the sky at around midnight local time. At a declination of +36°28', it is easiest to see from the northern hemisphere and cannot be seen from latitudes much south of 33°S. At magnitude 5.9, M13 is quite faint, and certainly not visible to the naked eye, but can be viewed through a pair of binoculars or a small telescope.

• June 2 - M12 well placed for observation. The globular cluster M12 (NGC 6218) in Ophiuchus will be well placed for observation. It will reach its highest point in the sky at around midnight local time. At a declination of -01°57', it is visible across much of the world; it can be seen at latitudes between 68°N and 71°S. At magnitude 6.6, M12 is quite faint, and certainly not visible to the naked eye, but can be viewed through a pair of binoculars or a small telescope.

• June 3 - Saturn at opposition - 06:25 UTC. Planet Saturn will be at its closest approach to Earth, in the constellation Opichius, and its face will be fully illuminated by the Sun. It will reach its highest point in the sky at around midnight local time. Saturn will be brighter than any other time of the year and visible all night long. This is the best time to view and photograph Saturn and its moons. Over the weeks following its opposition, Saturn will reach its highest point in the sky four minutes earlier each night, gradually receding from the pre-dawn morning sky while remaining visible in the evening sky for a few months.

• June 5 - New Moon - 03:01 UTC. The Moon will pass close to the Sun and become lost in the Sun's glare for a few days. This is the best time of the month to observe faint objects such as galaxies and star clusters because there is no moonlight to interfere.

• June 5 - Mercury at greatest elongation west - 12:43 UTC. Planet Mercury will reach greatest western elongation of 24.2 degrees from the Sun. Across much of the world, Mercury will be well placed for observation, shining brightly at mag -1.9. This is the best time to view Mercury since it will be at its highest point above the horizon in the morning sky. Look for the planet low in the eastern sky just before sunrise. Over the coming weeks, the distance between Mercury and the Sun will decrease each morning, and it will gradually sink back into the Sun's glare.

• June 5 - M10 well placed for observation. The globular cluster M10 (NGC 6254) in Ophiuchus will be well placed for observation. It will reach its highest point in the sky at around midnight local time. At a declination of -04°05', it is visible across much of the world; it can be seen at latitudes between 65°N and 74°S. At magnitude 6.6, M10 is quite faint, and certainly not visible to the naked eye, but can be viewed through a pair of binoculars or a small telescope.

• June 6 - Venus at superior solar conjunction - 21:15 UTC. From our vantage point on the Earth, Venus will appear very close to the Sun in the sky as it passes around the far side of the solar system from the Earth. At closest approach, Venus and the Sun will appear at a separation of only 0°00', making Venus totally unobservable for several weeks while it is lost in the Sun's glare. Venus will also pass apogee – the time when it is most distant from the Earth – within a few days of the same time, since it will lie exactly opposite to the Earth in the Solar System. It will move to a distance of 1.74 AU from the Earth, making it appear small and very distant. If it could be observed, it would measure 9.6 arcsec in diameter, whilst appearing completely illuminated. Venus's reaching superior conjunction marks the end of its apparition in the morning sky and its transition to become an evening object over the next few weeks.

• June  6 - M62 well placed for observation. Across much of the world the globular cluster M62 (NGC 6266) in Ophiuchus will be well placed for observation. It will reach its highest point in the sky at around midnight local time. At a declination of -30°07', it is easiest to see from the southern hemisphere and cannot be seen from latitudes much north of 39°N. At magnitude 6.6, M62 is quite faint, and certainly not visible to the naked eye, but can be viewed through a pair of binoculars or a small telescope.

• June 9 - C/2015 WZ (PANSTARRS) reaches its brightest. Comet C/2015 WZ (PANSTARRS) is forecast to reach its brightest, at around mag 10.6. It will lie at a distance of 1.58 AU from the Sun, and at a distance of 1.18 AU from the Earth.

• June 10 - M92 well placed for observation. The globular cluster M92 (NGC 6341) in Hercules will be well placed for observation. It will reach its highest point in the sky at around midnight local time. At a declination of +43°07', it is easiest to see from the northern hemisphere and cannot be seen from latitudes much south of 26°S. At magnitude 6.5, M92 is quite faint, and certainly not visible to the naked eye, but can be viewed through a pair of binoculars or a small telescope.

• June 11 - Conjunction between the Moon and Jupiter - 18:45 UTC. The Moon and Jupiter will make a close approach, passing within 1°25' of each other. At the moment of closest approach, the Moon will be at mag -11.7, and Jupiter at mag -2.0, both in the constellation Leo. The pair will be too widely separated to fit within the field of view of a telescope, but will be visible to the naked eye or through a pair of binoculars.

• June 12 - Moon at first quarter - 08:11 UTC. Over the next few days, the distance between the Moon and Sun will increase each night as the Moon approaches full phase.

• June 15 - NGC 6388 well placed for observation. Across much of the world, the globular cluster NGC 6388 in Scorpius will be well placed for observation. It will reach its highest point in the sky at around midnight local time. At a declination of -44°43', it is easiest to see from the southern hemisphere and cannot be seen from latitudes much north of 25°N. At magnitude 6.9, NGC6388 is quite faint, and certainly not visible to the naked eye, but can be viewed through a pair of binoculars or a small telescope.

• June 16 - M6 well placed for observation. The butterfly open star cluster (M6, NGC 6405) in Scorpius will be well placed for observation across much of the world. It will reach its highest point in the sky at around midnight local time. At a declination of -32°13', it is easiest to see from the southern hemisphere and cannot be seen from latitudes much north of 37°N. At magnitude 4.2, M6 is tricky to make out with the naked eye except from a dark site, but is visible through a pair of binoculars or a small telescope.

• June 16 - NGC 6397 well placed for observation. The globular cluster NGC 6397 in Ara will be well placed for observation. It will reach its highest point in the sky at around midnight local time. At a declination of -53°40', it is easiest to see from the southern hemisphere and cannot be seen from latitudes much north of 16°N. At magnitude 5.7, NGC6397 is too faint to be seen with the naked eye from any but the very darkest sites, but is visible through a pair of binoculars or a small telescope.

• June 17 - IC4665 well placed for observation. The open star cluster IC 4665 in Ophiuchus will be well placed for observation. It will reach its highest point in the sky at around midnight local time. At a declination of +05°43', it is visible across much of the world; it can be seen at latitudes between 75°N and 64°S. At magnitude 4.2, IC4665 is tricky to make out with the naked eye except from a dark site but is visible through a pair of binoculars or a small telescope.

• June 19 - Conjunction between the Moon and Saturn - 01:05 UTC. The Moon and Saturn will make a close approach, passing within 3°13' of each other. At the moment of closest approach, the Moon will be at mag -12.5, and Saturn at mag 0.8, both in the constellation Ophiuchus. The pair will be too widely separated to fit within the field of view of a telescope, but will be visible to the naked eye or through a pair of binoculars.

• June 19 - M7 well placed for observation. Across much of the world, the Ptolemy cluster (M7, NGC 6475) in Scorpius will be well placed for observation. It will reach its highest point in the sky at around midnight local time. At a declination of -34°49', it is easiest to see from the southern hemisphere and cannot be seen from latitudes much north of 35°N. At magnitude 3.3, M7 is tricky to make out with the naked eye except from a dark site, but is visible through a pair of binoculars or a small telescope.

• June 20 - Ophiuchid meteor shower. The Ophiuchid meteor shower will reach its maximum rate of activity on June 20, 2016, but some shooting stars associated with the shower are expected to be visible each night from May 19 to July. The maximum rate of meteors expected to be visible from a dark location is around 5 per hour (ZHR). The Full Moon will severely limit the observations that will be possible.

• June 20 - Full Moon - 11:04 UTC. The Moon will reach full phase, making it visible for much of the night. At the moment when the Moon reaches full phase, it will lie at a declination of -18°33' in the constellation Sagittarius, and so will appear highest in the southern hemisphere. It will be visible from all latitudes north of 61°N. Its distance from the Earth will be 394 000 km. Over the nights following June 20, the Moon will rise around an hour later each day so as to become prominent later in the night. Within a few days, it will only be visible in the pre-dawn and early-morning sky. By the time it reaches last quarter, a week after full moon, it will rise at around midnight and set at around noon. Full Moons are traditionally given names according to the season in which they fall, and this will be the third full moon of spring 2016, traditionally called the Flower Moon. This full moon was known by early Native American tribes as the Full Strawberry Moon because it signaled the time of year to gather ripening fruit. It also coincides with the peak of the strawberry harvesting season. This moon has also been known as the Full Rose Moon and the Full Honey Moon.

• June 20 - June Solstice - 22:34 UTC. The North Pole of the Earth will be tilted toward the Sun, which will have reached its northernmost position in the sky and will be directly over the Tropic of Cancer at 23.44 degrees north latitude. This is the first day of summer (summer solstice) in the northern hemisphere and the first day of winter (winter solstice) in the southern hemisphere.

• June 22 - NGC 6530 well placed for observation. The open star cluster NGC 6530, close to the lagoon nebula (M8) in Sagittarius, will be well placed for observation. It will reach its highest point in the sky at around midnight local time. At a declination of -24°19', it is easiest to see from the southern hemisphere and cannot be seen from latitudes much north of 45°N. At magnitude 4.6, NGC6530 is too faint to be seen with the naked eye from any but the very darkest sites but is visible through a pair of binoculars or a small telescope.

• June 23 - NGC 6541 well placed for observation. Across much of the world, the globular cluster NGC 6541 in Corona Australis will be well placed for observation. It will reach its highest point in the sky at around midnight local time. At a declination of -43°42', it is easiest to see from the southern hemisphere and cannot be seen from latitudes much north of 26°N. At magnitude 6.6, NGC6541 is quite faint, and certainly not visible to the naked eye, but can be viewed through a pair of binoculars or a small telescope.

• June 28 - Conjunction between the Moon and Uranus - 23:55 UTC. The Moon and Uranus will make a close approach, passing within 2°34' of each other. At the moment of closest approach, the Moon will be at mag -11.6, and Uranus at mag 5.9, both in the constellation Pisces. The pair will be too widely separated to fit within the field of view of a telescope, but will be visible to the naked eye or through a pair of binoculars.

• June 28 - NGC 6633 well placed for observation. The open star cluster NGC 6633 in Ophiuchus will be well placed for observation. It will reach its highest point in the sky at around midnight local time. At a declination of +06°34', it is visible across much of the world; it can be seen at latitudes between 76°N and 63°S. At magnitude 4.6, NGC6633 is too faint to be seen with the naked eye from any but the very darkest sites but is visible through a pair of binoculars or a small telescope.

• June 30 - M22 well placed for observation. The globular cluster M22 in Sagittarius, near the Galactic center, will be well placed for observation. It will reach its highest point in the sky at around midnight local time. At a declination of -23°54', it is easiest to see from the southern hemisphere and cannot be seen from latitudes much north of 46°N. At magnitude 5.1, M22 is too faint to be seen with the naked eye from any but the very darkest sites but is visible through a pair of binoculars or a small telescope.

Video courtesy Hubble Space Telescope

Sources: InTheSky (Dominic Ford), SeaSky