Night sky guide for August 2017

Night sky guide for August 2017

Solar eclipse chasers, especially those living in the United States, have waited for this month for many years. On August 21, a rare, once-in-a-lifetime event for viewers in the US will make the Moon completely block out the Sun - total solar eclipse, revealing the Sun's beautiful outer atmosphere known as the corona. The last total solar eclipse visible in the continental United States occurred in 1979 and the next one will not take place until 2024.

The second eclipse of the month, this time a partial lunar one, will take place on August 7, on the same day our Moon reaches its full phase. This eclipse will be visible throughout most of eastern Africa, central Asia, the Indian Ocean, and Australia. 

Perseid meteor shower, arguably the second big event of the month, will peak during the night of August 12 and the morning of August 13. A Waning Gibbous Moon will hinder a good view of the meteor shower, but the Perseids are so bright and numerous that it should still be a good show.

New Moon, that night of the month when the Moon will be located on the same side of the Earth as the Sun and will not be visible in the night sky, will occur on August 21. 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.

  • August 3 - Close approach of the Moon and Saturn - 07:55 UTC. The Moon and Saturn will make a close approach, passing within 3°25' of each other. The Moon will be at mag -12.3, and Saturn at mag 0.1, 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. The Moon will be 11 days old. 

  • August 5 - Conjunction of the Moon and Pluto - 12:13 UTC. The Moon and Pluto will share the same right ascension, with the Moon passing 2°26' to the north of Pluto. The Moon will be at mag -12.5, and Pluto at mag 14.9, both in the constellation Sagittarius. The pair will be too widely separated to fit within the field of view of a telescope but will be visible through a pair of binoculars. The Moon will be 13 days old. 

  • August 7 - Full Moon - 18:12 UTC. The Moon will be located on the opposite side of the Earth as the Sun and its face will be will be fully illuminated. At this time in its monthly cycle of phases, the Moon lies almost directly opposite the Sun in the sky, placing it high above the horizon for much of the night. The sequence of full moons through the year are often assigned names according to the seasons in which they fall. This month's will be the second to fall in summer 2017 – the Grain Moon. This full moon was known by early Native American tribes as the Full Sturgeon Moon because the large sturgeon fish of the Great Lakes and other major lakes were more easily caught at this time of year. This moon has also been known as the Green Corn Moon and the Grain Moon. Over the nights following August 7, the Moon will rise around an hour later each day, becoming 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. At the exact moment when the Moon reaches full phase, it will lie at a declination of -15°30' in the constellation Capricornus, and so will appear highest in the southern hemisphere. It will be visible from all latitudes north of 64°N. Its distance from the Earth will be 394 000 km (244 820 miles).

  • August 7 - Partial Lunar Eclipse - 18:12 UTC. A partial lunar eclipse occurs when the Moon passes through the Earth's partial shadow, or penumbra, and only a portion of it passes through the darkest shadow, or umbra. During this type of eclipse a part of the Moon will darken as it moves through the Earth's shadow. The eclipse will be visible throughout most of eastern Africa, central Asia, the Indian Ocean, and Australia.

Partial lunar eclipse August 7, 2017

  • August 10 - Close approach of the Moon and Neptune - 23:06 UTC. The Moon and planet Neptune will make a close approach, passing within 0°49' of each other. The Moon will be at mag -12.5, and Neptune at mag 7.8, both in the constellation Aquarius. The pair will be a little too widely separated to fit comfortably within the field of view of a telescope but will be visible through a pair of binoculars. The Moon will be 17 days old.

  • August 12, 13 - Perseid meteor shower. The Perseid meteor shower is one of the best meteor showers to observe, producing up to 80 meteors per hour at its peak. It is produced by comet Swift-Tuttle, which was discovered in 1862. The Perseids are famous for producing a large number of bright meteors. The shower runs annually from July 17 to August 24. It peaks this year on the night of August 12 and the morning of August 13. The waning gibbous moon will block out many of the fainter meteors this year, but the Perseids are so bright and numerous that it should still be a good show. Best viewing will be from a dark location after midnight. Meteors will radiate from the constellation Perseus, but can appear anywhere in the sky.

  • August 12 - Conjunction of Venus and Ceres - 15:42 UTC. Venus and Ceres will share the same right ascension, with Venus passing 2°26' to the south of 1 Ceres. Venus will be at mag -4.0, and 1 Ceres at mag 8.9, both in the constellation Gemini. The pair will be too widely separated to fit within the field of view of a telescope but will be visible through a pair of binoculars.

  • August 13 - M15 well placed for observation. The globular cluster M15 (NGC 7078) in Pegasus will be well placed for observation. It will reach its highest point in the sky at around midnight local time. At a declination of +12°10', it is easiest to see from the northern hemisphere; it can be seen at latitudes between 82°N and 57°S. At magnitude 6.4, M15 is quite faint, and certainly not visible to the naked eye, but can be viewed through a pair of binoculars or a small telescope.

  • August 13 - Conjunction of the Moon and Eris - 05:03 UTC. The Moon and Eris will share the same right ascension, with the Moon passing 8°07' to the north of Eris. The Moon will be 21 days old. The Moon will be at mag -12.3 in the constellation Pisces, and Eris at mag 18.8 in the neighboring constellation of Cetus.

  • August 14 - M2 well placed for observation. The globular cluster M2 (NGC 7089) in Aquarius will be well placed for observation. It will reach its highest point in the sky at around midnight local time. At a declination of -00°49', it is visible across much of the world; it can be seen at latitudes between 69°N and 70°S. At magnitude 6.5, M2 is quite faint, and certainly not visible to the naked eye, but can be viewed through a pair of binoculars or small telescope.

  • August 15 - Moon at Last Quarter - 01:16 UTC. The Moon will be prominent in the dawn sky, rising at around midnight. Over coming days, the Moon will rise later each day, so that it is visible for less time before sunrise and it less far above the eastern horizon before dawn. By the time it reaches New Moon, it will rise at around dawn and set at around dusk, making it visible only during the daytime.

  • August 18 - Conjunction of the Moon and Ceres - 20:06 UTC. The Moon and Ceres will share the same right ascension, with the Moon passing 4°56' to the south of 1 Ceres. The Moon will be at mag -10.4, and 1 Ceres at mag 8.9, both in the constellation Gemini. The pair will be too widely separated to fit within the field of view of a telescope but will be visible through a pair of binoculars. The Moon will be 26 days old.

  • August 19 - Close approach of the Moon and Venus - 04:26 UTC. The Moon and Venus will make a close approach, passing within 2°14' of each other. The Moon will be at mag -10.1, and Venus at mag -4.0, both in the constellation Gemini. 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.

  • August 19 - Conjunction of the Moon and Venus - 04:45 UTC. The Moon and Venus will share the same right ascension, with the Moon passing 2°14' to the south of Venus. At around the same time, the two objects will also make a close approach, technically called an appulse. The Moon will be at mag -10.1, and Venus at mag -4.0, both in the constellation Gemini. 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. The Moon will be 27 days old.

  • August 21 - New Moon - 18:31 UTC. The Moon will be located on the same side of the Earth as the Sun and will not be visible in the night sky. 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. The Moon's orbital motion carries it around the Earth once every four weeks, and as a result its phases cycle from new moon, through first quarter, full moon and last quarter, back to new moon once every 29.5 days. This motion also means that the Moon travels more than 12° across the sky from one night to the next, causing it to rise and set nearly an hour later each day. At new moon, the Earth, Moon and Sun all lie in a roughly straight line, with the Moon in the middle, appearing in front of the Sun's glare. In this configuration, we see almost exactly the opposite half of the Moon to that which is illuminated by the Sun, making it doubly unobservable because the side we see is unilluminated. Over coming days, the Moon will rise and set an hour later each day, becoming visible in the late afternoon and dusk sky as a waxing crescent which sets soon after the Sun. By first quarter, in a week's time, it will be visible until around midnight.

  • August 21 - Total solar eclipse - 18:26 UTC. A total solar eclipse occurs when the moon completely blocks the Sun, revealing the Sun's beautiful outer atmosphere known as the corona. This is a rare, once-in-a-lifetime event for viewers in the United States. The last total solar eclipse visible in the continental United States occurred in 1979 and the next one will not take place until 2024. The path of totality will begin in the Pacific Ocean and travel through the center of the United States. The total eclipse will be visible in parts of Oregon, Idaho, Wyoming, Nebraska, Missouri, Kentucky, Tennessee, North Carolina, and South Carolina before ending in the Atlantic Ocean. A partial eclipse will be visible in most of North America and parts of northern South America.

Total Solar Eclipse of August 21, 2017

  • August 22 - Conjunction of the Moon and Mercury - 05:58 UTC. The Moon and Mercury will share the same right ascension, with the Moon passing 6°09' to the north of Mercury.  The Moon will be at mag -6.4 in the constellation Leo, and Mercury at mag 3.8 in the neighboring constellation of Sextans. The Moon will be 1 day old.

  • August 25 - Conjunction of the Moon and Makemake - 02:16 UTC. The Moon and Makemake will share the same right ascension, with the Moon passing 26°05' to the south of Makemake. The Moon will be at mag -10.4 in the constellation Virgo, and 136472 Makemake at mag 17.1 in the neighboring constellation of Coma Berenices.

  • August 25 - Close approach of the Moon and Jupiter - 15:13 UTC. The Moon and Jupiter will make a close approach, passing within 3°17' of each other. The Moon will be 4 days old. The Moon will be at mag -10.7, and Jupiter at mag -1.8, both in the constellation Virgo. 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.

  • August 26 - Conjunction of the Moon and Haumea - 13:06 UTC. The Moon and Haumea will share the same right ascension, with the Moon passing 24°19' to the south of Haumea. The Moon will be 5 days old. The Moon will be at mag -11.0 in the constellation Virgo, and 136108 Haumea at mag 17.4 in the neighboring constellation of Bootes.

  • August 26 - Mercury at inferior solar conjunction - 20:36 UTC. Mercury will pass very close to the Sun in the sky as its orbit carries it between the Sun and Earth. This occurs once in every synodic cycle of the planet (116 days), and marks the end of Mercury's apparition in the evening sky and its transition to become a morning object over the next few weeks. At closest approach, Mercury will appear at a separation of only 4°13' from the Sun, making it totally unobservable for several weeks while it is lost in the Sun's glare. Mercury will also pass perigee – the time when it is closest to the Earth – at around the same time, since it will lie on exactly the same side of the Sun as the Earth in the Solar System. It will move to within a distance of 0.62 AU from the Earth, making it appear with its largest angular size. If it could be observed, it would measure 10.8 arcsec in diameter, whilst appearing completely unilluminated.

  • August 27 - Conjunction of Uranus and Eris - 21:04 UTC. Uranus and Eris will share the same right ascension, with Uranus passing 12°31' to the north of Eris. Uranus will be at mag 5.7 in the constellation Pisces, and Eris at mag 18.8 in the neighboring constellation of Cetus.

  • August 29 - Moon at First Quarter - 08:14 UTC. The Moon will be prominent in the evening sky, setting around midnight. At this time in its monthly cycle of phases, it appears almost exactly half illuminated. Over coming days, the Moon will set later each day, becoming visible for more of the night. Within a few days, it will not make it very far above the eastern horizon before nightfall. By the time it reaches full phase, it will be visible for much of the night, rising at around dusk and setting at around dawn.

  • August 30 - Close approach of the Moon and Saturn - 14:51 UTC. The Moon and Saturn will make a close approach, passing within 3°32' of each other. The Moon will be 9 days old. The Moon will be at mag -12.0, and Saturn at mag 0.2, 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.

Video courtesy Hubble Space Telescope

Sources: In The Sky (Dominic Ford), NASA

Featured image credit: SkySeeker. Edit: The Watchers

Comments

Me. 2 months ago

Um...no. Pluto, in fact, CANNOT be seen with binoculars....from earth anyway.

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