Night sky guide for October 2017

Night sky guide for October 2017

October 2017 has two meteor showers, one minor - Draconids, on October 8, and one major - Orionids, on October 21 and 22. Draconids will be mostly blocked by the nearly full moon, but Orionids will present an interesting opportunity as the crescent Moon will set early in the evening leaving dark skies for what should be a good show.

This month's Full Moon is on October 5. This full moon is known as the Harvest Moon, full moon that occurs closest to the September equinox each year. This moon has also been known as the Travel Moon and the Blood Moon. 

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 October 19.

At least 2 near-Earth asteroids will flyby within 1 lunar distance this month. Asteroid 2017 SX17 will fly past us at a distance of 0.23 LD (~88 320 km / 54 879 miles) on October 2, 2017. This is the 34th known asteroid to flyby Earth since the start of the year. Asteroid 2012 TC4 will fly past our planet at a very close distance of 0.13 LD (~50 100 km / 31 140 miles) at 05:42 UTC October 12, 2017. Current estimates suggest it should peak around mag 13 at closest approach. At the time of closest approach, 2012 TC4 will be over a point in the ocean south of Australia.

  • October 1 - M10 well placed for observation. M110, the brightest satellite galaxy of the Andromeda galaxy (M31) will be well placed for observation. It will reach its highest point in the sky at around midnight local time. At a declination of +41°40', it is easiest to see from the northern hemisphere but cannot be seen from latitudes much south of 28°S. At magnitude 8.0, M110 is quite faint, and certainly not visible to the naked eye, but can be viewed through a pair of binoculars or a small telescope.

  • October 1 - M31 well placed for observation. The Andromeda galaxy (M31) will be well placed for observation. It will reach its highest point in the sky at around midnight local time.At a declination of +41°16', it is easiest to see from the northern hemisphere but cannot be seen from latitudes much south of 28°S. At magnitude 3.5, M31 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.

  • October 1 - M31 well placed for observation. M32, the second brightest satellite galaxy of the Andromeda galaxy (M31) after M110 will be well placed for observation. It will reach its highest point in the sky at around midnight local time. At a declination of +40°52', it is easiest to see from the northern hemisphere but cannot be seen from latitudes much south of 29°S. At magnitude 8.2, M32 is quite faint, and certainly not visible to the naked eye, but can be viewed through a pair of binoculars or a small telescope.

  • October 2 - Asteroid 2017 SX17 passing within 1 lunar distance - 10:20 UTC. A small asteroid designated 2017 SX17 will flyby Earth at a very close distance of 0.23 LD (~88 320 km / 54 879 miles) on October 2, 2017. This is the 34th known asteroid to flyby Earth since the start of the year. Asteroid 2017 SX17 belongs to the Apollo group of asteroids. It was first observed at Mt. Lemmon Survey on September 29, 2017. The estimated size of this object is between 6.5 and 15 m (21 - 49 feet), according to CNEOS. Minor Planet Center estimated its diameter between 3 and 12 m (9 and 39 feet). Read more about this event.

  • October 3 - NGC 253 well placed for observation. Across much of the world, the Sculptor galaxy (NGC 253) will be well placed for observation. It will reach its highest point in the sky at around midnight local time. At a declination of -25°16', it is easiest to see from the southern hemisphere but cannot be seen from latitudes much north of 44°N. At magnitude 7.1, NGC253 is quite faint, and certainly not visible to the naked eye, but can be viewed through a pair of binoculars or a small telescope.

  • October 3 - Close approach of the Moon and Neptune. The Moon and Neptune will make a close approach, passing within 0°42' of each other. The Moon will be 13 days old. The Moon will be at mag -12.6, 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.

  • October 4 - SMC well placed for observation. Across much of the world, the Milky Way's dwarf companion, the Small Magellanic Cloud (SMC), in Tucana will be well placed for observation. It will reach its highest point in the sky at around midnight local time. At a declination of -72°48', it is easiest to see from the southern hemisphere but cannot be seen from latitudes much north of 2°S. At magnitude 2.7, SMC is visible to the naked eye, but best viewed through a pair of binoculars.

  • October 4 - NGC 300 well placed for observation. Across much of the world NGC 300, a spiral galaxy in Sculptor will be well placed for observation. It will reach its highest point in the sky at around midnight local time. At a declination of -37°40', it is easiest to see from the southern hemisphere but cannot be seen from latitudes much north of 32°N. At magnitude 9.0, NGC300 is quite faint, and certainly not visible to the naked eye, but can be viewed through a pair of binoculars or a small telescope.

  • October 5 - Conjunction of Venus and Mars - 13:23 UTC. Venus and Mars will share the same right ascension, with Venus passing 0°13' to the north of Mars. Venus will be at mag -3.9, and Mars at mag 1.8, both in the constellation Leo. The pair will be close enough to fit within the field of view of a telescope, but will also be visible to the naked eye or through a pair of binoculars.

  • October 5 - Full Moon - 18:41 UTC. The Moon will reach full phase. 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 first to fall in northern hemisphere's autumn 2017 – the Harvest Moon, full moon that occurs closest to the September equinox each year. This full moon was known by early Native American tribes as the Full Hunters Moon because at this time of year the leaves are falling and the game is fat and ready to hunt. This moon has also been known as the Travel Moon and the Blood Moon. Over the nights following October 5, 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 +01°20' in the constellation Cetus, and so will appear high in the sky at all but the most extreme latitudes. It will be visible at all latitudes between 81°N and 78°S. Its distance from the Earth will be 373 000 km (231 771 miles).

  • October 6 - NGC 362 well placed for observation. Across much of the world, the globular cluster NGC 362 in Tucana will be well placed for observation. It will reach its highest point in the sky at around midnight local time. At a declination of -70°51', it is easiest to see from the southern hemisphere but cannot be seen from latitudes much north of 0°S. At magnitude 6.6, NGC362 is quite faint, and certainly not visible to the naked eye, but can be viewed through a pair of binoculars or a small telescope.

  • October 6 - Conjunction of the Moon and Eris - 17:58 UTC. The Moon and 136199 Eris will share the same right ascension, with the Moon passing 8°18' to the north of Eris. The Moon will be 16 days old. The Moon will be at mag -12.7 in the constellation Pisces, and Eris at mag 18.8 in the neighboring constellation of Cetus.

  • October 8 - Mercury at greatest brightness - 10:14 UTC. In the southern hemisphere, Mercury will be well placed for observation in the evening sky, shining brightly at mag -1.7. Mercury's orbit lies closer to the Sun than the Earth's, meaning that it always appears close to the Sun and is very difficult to observe most of the time. It is observable only for a few days each time it reaches greatest separation from the Sun – moments referred to as greatest elongation.

  • October 8 - Mercury at superior solar conjunction - 20:38 UTC. Mercury will pass very close to the Sun in the sky as its orbit carries it around the far side of the solar system from the Earth. This occurs once in every synodic cycle of the planet (116 days) and marks the end of Mercury's apparition in the morning sky and its transition to becoming an evening object over the next few weeks. At closest approach, Mercury will appear at a separation of only 1°06' from the Sun, making it totally unobservable for several weeks while it is lost in the Sun's glare. Mercury will also pass apogee – the time when it is most distant from the Earth – at around the same time since it will lie exactly opposite to the Earth in the Solar System. It will move to a distance of 1.41 AU from the Earth, making it appear small and very distant. If it could be observed, it would measure 4.8 arcsec in diameter, whilst appearing completely illuminated.

  • October 8 - Draconid meteor shower. This is a minor meteor shower producing only about 10 meteors per hour. It is produced by dust grains left behind by comet 21P Giacobini-Zinner, which was first discovered in 1900. The Draconids is an unusual shower in that the best viewing is in the early evening instead of early morning like most other showers. The shower runs annually from October 6 - 10 and peaks this year on the night of the 8th. Unfortunately, the nearly full moon will block all but the brightest meteors this year. If you are extremely patient, you may be able to catch a few good ones. Best viewing will be in the early evening from a dark location far away from city lights. Meteors will radiate from the constellation Draco, but can appear anywhere in the sky.

  • October 9 - Conjunction of Mercury and Makemake - 22:53 UTC. Mercury and Makemake will share the same right ascension, with Mercury passing 29°09' to the south of Makemake. Mercury will be at mag -1.7 in the constellation Virgo, and Makemake at mag 17.0 in the neighboring constellation of Coma Berenices.

  • October 12 - Moon at Last Quarter - 12:27 UTC. The Moon will be prominent in the dawn sky, rising at around midnight.

  • October 12 - Asteroid 2012 TC4 passing within 1 lunar distance - 05:42 UTC. New observations of near-Earth asteroid designated 2012 TC4 reveal it will fly past our planet at a very close distance of 0.13 LD (~50 100 km / 31 140 miles) at 05:42 UTC October 12, 2017. Current estimates suggest it should peak around mag 13 at closest approach. At the time of closest approach, 2012 TC4 will be over a point in the ocean south of Australia. Read more about this event.

  • October 13 - Close approach of the Moon and M44 - 20:03 UTC. The Moon and M44 will make a close approach, passing within 2°53' of each other. The Moon will be 23 days old. The Moon will be at mag -11.6, and M44 at mag 3.1, both in the constellation Cancer. 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.

  • October 13 - Conjunction of the Moon and Ceres - 20:51 UTC. The Moon and Ceres will share the same right ascension, with the Moon passing 5°45' to the south of 1 Ceres. The Moon will be 23 days old. The Moon will be at mag -11.6, and Ceres at mag 8.7, both in the constellation Cancer.

  • October 14 - M33 well placed for observation. The Triangulum galaxy (M33) 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°39', it is easiest to see from the northern hemisphere but cannot be seen from latitudes much south of 39°S. At magnitude 5.7, M33 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.

  • October 15 - Comet C/2017 O1 (ASASSN) at perihelion. Comet C/2017 O1 (ASASSN) will make its closest approach to the Sun, at a distance of 1.49 AU.

  • October 16 - Comet C/2017 O1 (ASASSN) reaches its brightest. Comet C/2017 O1 (ASASSN) is forecast to reach its brightest, at around mag 7.6. It will lie at a distance of 1.49 AU from the Sun, and at a distance of 0.72 AU from the Earth.

  • October 16 - Eris at opposition - 11:39 UTC. 136199 Eris will be well placed for observation, in the constellation Cetus. It will be visible for much of the night, reaching its highest point in the sky at around midnight local time.

  • October 17 - Haumea at solar conjunction - 09:52 UTC. Haumea will pass very close to the Sun in the sky as its orbit carries it around the far side of the solar system from the Earth. At closest approach, Haumea will appear at a separation of only 27° from the Sun, making it totally unobservable for several weeks while it is lost in the Sun's glare. At around the same time, Haumea will also be at its most distant from the Earth – receding to a distance of 51.42 AU – since the two planets will lie on opposite sides of the solar system. If Haumea could be observed at this time, it would appear at its smallest and faintest on account of its large distance. It would measure 0.0 arcsec in diameter. Over following weeks and months, Haumea will re-emerge to the west of the Sun, gradually becoming visible for ever-longer periods in the pre-dawn sky. After around six months, it will reach opposition, when it will be visible for virtually the whole night.

  • October 18 - Conjunction of the Moon and Venus - 00:23 UTC. The Moon and Venus will share the same right ascension, with the Moon passing 1°58' to the north of Venus. The Moon will be 28 days old. The Moon will be at mag -9.0, and Venus at mag -3.9, 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.

  • October 18 - Conjunction of Jupiter and Mercury - 14:53 UTC. Jupiter and Mercury will share the same right ascension, with Jupiter passing 1°01' to the north of Mercury. Jupiter will be at mag -1.7, and Mercury at mag -0.9, 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.

  • October 18 - Conjunction of the Moon and Makemake - 21:15 UTC. The Moon and Makemake will share the same right ascension, with the Moon passing 26°01' to the south of Makemake. The Moon will be 28 days old. The Moon will be at mag -7.6 in the constellation Virgo, and Makemake at mag 17.0 in the neighboring constellation of Coma Berenices.

  • October 19 - Uranus at opposition - 17:21 UTC. Uranus will be well placed for observation, in the constellation Pisces. It will be visible for much of the night, reaching its highest point in the sky at around midnight local time.

  • October 19 - New Moon - 19:13 UTC. The Moon will pass close to the Sun and become lost in the Sun's glare for a few days. 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. 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. 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.

  • October 20 - Conjunction of the Moon and Mercury - 07:34 UTC. The Moon and Mercury will share the same right ascension, with the Moon passing 5°12' to the north of Mercury. The Moon will be 1 days old. The Moon will be at mag -6.7, and Mercury at mag -0.8, both in the constellation Virgo. The pair will be too widely separated to fit within the field of view of a telescope or pair of binoculars but will be visible to the naked eye.

  • October 20 - Conjunction of the Moon and Haumea - 07:54 UTC. The Moon and Haumea will share the same right ascension, with the Moon passing 24°13' to the south of Haumea. The Moon will be 1 days old. The Moon will be at mag -6.8 in the constellation Virgo, and Haumea at mag 17.4 in the neighboring constellation of Bootes.

  • October 20 - Conjunction of Mercury and Haumea - 10:15 UTC. Mercury and Haumea will share the same right ascension, with Mercury passing 29°27' to the south of 136108 Haumea. Mercury will be at mag -0.8 in the constellation Virgo, and Haumea at mag 17.4 in the neighboring constellation of Bootes.

  • October 21, 22 - Orionids Meteor Shower. This is a major (Class I) shower producing between 15 and 20 meteors per hour at its peak. It is produced by dust grains left behind by comet Halley, which has been known and observed since ancient times. The shower runs annually from October 2 to November 7 and peaks this year on the night of October 21 and the morning of October 22. The crescent moon will set early in the evening leaving dark skies for what should be a good show. Best viewing will be from a dark location after midnight. Meteors will radiate from the constellation Orion but can appear anywhere in the sky.

  • October 23 - Asteroid 2 Pallas at opposition - 12:27 UTC. Asteroid 2 Pallas will be well placed for observation, lying in the constellation Eridanus, well above the horizon for much of the night. Regardless of your location on the Earth, 2 Pallas will reach its highest point in the sky at around midnight local time.

  • October 24 - Close approach of the Moon and Saturn - 12:15 UTC. The Moon and Saturn will make a close approach, passing within 3°14' of each other. The Moon will be 5 days old. The Moon will be at mag -10.8, and Saturn at mag 0.4, 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.

  • October 26 - NGC 869 well placed for observation. The open star cluster NGC 869 in Perseus, also known as the western half of the double cluster will be well placed for observation. It will reach its highest point in the sky at around midnight local time. At a declination of +57°09', it is easiest to see from the northern hemisphere but cannot be seen from latitudes much south of 12°S. At magnitude 4.0, NGC869 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.

  • October 26 - Conjunction of the Moon and Pluto - 11:24 UTC. The Moon and Pluto will share the same right ascension, with the Moon passing 2°16' to the north of Pluto. The Moon will be 7 days old. The Moon will be at mag -11.5, and Pluto at mag 14.7, 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.

  • October 26 - Jupiter at solar conjunction - 18:14 UTC. Jupiter will pass very close to the Sun in the sky as its orbit carries it around the far side of the solar system from the Earth. At closest approach, Jupiter will appear at a separation of only 1°00' from the Sun, making it totally unobservable for several weeks while it is lost in the Sun's glare. At around the same time, Jupiter will also be at its most distant from the Earth – receding to a distance of 6.43 AU – since the two planets will lie on opposite sides of the solar system. If Jupiter could be observed at this time, it would appear at its smallest and faintest on account of its large distance. It would measure 30.0 arcsec in diameter. Over following weeks and months, Jupiter will re-emerge to the west of the Sun, gradually becoming visible for ever-longer periods in the pre-dawn sky. After around six months, it will reach opposition, when it will be visible for virtually the whole night. 

  • October 27 - NGC 884 well placed for observation. The open star cluster NGC 884 in Perseus, also known as the eastern half of the double cluster will be well placed for observation. It will reach its highest point in the sky at around midnight local time. At a declination of +57°07', it is easiest to see from the northern hemisphere but cannot be seen from latitudes much south of 12°S. At magnitude 4.0, NGC884 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.

  • October 27 - Conjunction of Venus and Makemake - 09:30 UTC. Venus and Makemake will share the same right ascension, with Venus passing 28°44' to the south of Makemake. Venus will be at mag -3.9 in the constellation Virgo, and Makemake at mag 17.1 in the neighboring constellation of Coma Berenices.

  • October 28 - Moon at First Quarter -22:23 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.

  • October 28 - Comet 96P/Machholz at perihelion. Comet 96P/Machholz will make its closest approach to the Sun, at a distance of 0.12 AU.

  • October 28 - Comet 96P/Machholz reaches its brightest. Comet 96P/Machholz is forecast to reach its brightest, at around mag 2.1. It will lie at a distance of 0.12 AU from the Sun, and at a distance of 0.96 AU from the Earth.

  • October 30 - Asteroid 7 Iris at opposition. Asteroid 7 Iris will be well placed for observation, lying in the constellation Aries, well above the horizon for much of the night. Regardless of your location on the Earth, 7 Iris will reach its highest point in the sky at around midnight local time.

  • October 30 - Close approach of the Moon and Neptune - 21:25 UTC. The Moon and Neptune will make a close approach, passing within 0°50' of each other. The Moon will be 11 days old. The Moon will be at mag -12.4, and Neptune at mag 7.9, 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.

  • October 30 - Fornax well placed for observation. Across much of the world, the Fornax dwarf spheroidal galaxy 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°27', it is easiest to see from the southern hemisphere but cannot be seen from latitudes much north of 35°N. At magnitude 9.0, Fornax is quite faint, and certainly not visible to the naked eye, but can be viewed through a pair of binoculars or a small telescope.

Video courtesy Hubble Space Telescope

Sources: American Meteor SocietyIn The Sky by Dominic Ford, The Watchers

Featured image: Meteor shower by 7Themes. Edit: The Watchers

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