Night Sky Guide for March 2019

March 1 – Close approach of the Moon and Saturn – 18:28 UTC. The Moon, 25 days old, and Saturn will make a close approach, passing within 0°18' of each other. The Moon will be at mag -10.8, and Saturn at mag 0.4, both in the constellation Sagittarius. 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. At around the same time, the two objects will also share the same right ascension – called a conjunction.

March – Conjunction of the Moon and Saturn – 18:29 UTC. The Moon and Saturn will share the same right ascension, with the Moon passing 0°18' to the north of Saturn. At around the same time, the two objects will also make a close approach, technically called an appulse. The Moon will be at mag -10.8, and Saturn at mag 0.4, both in the constellation Sagittarius. 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.

March 2 – Conjunction of the Moon and Venus – 21:29 UTC. The Moon and Venus will share the same right ascension, with the Moon passing 1°12' 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 -10.3, and Venus at mag -4.1, both in the constellation Capricornus. 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.

March 2 – Close approach of the Moon and Venus – 21:49 UTC. The Moon and Venus will make a close approach, passing within 1°11' of each other. 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. At around the same time, the two objects will also share the same right ascension – called a conjunction.

March 3 – IC2602 well placed for observation. Across much of the world, the theta Carinae open star cluster (IC 2602, also known as the Southern Pleiades) will be well placed for observation. It will reach its highest point in the sky at around midnight local time. At a declination of -64°23', it is easiest to see from the southern hemisphere but cannot be seen from latitudes much north of 5°N. At magnitude 1.9, IC2602 is visible to the naked eye, but best viewed through a pair of binoculars.

March 6 – New Moon – 16:05 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. Click here for more information about the Moon's phases. 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. 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.

March 7 – Neptune at solar conjunction – 01:02 UTC. Neptune 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, Neptune will appear at a separation of only 0°57' from the Sun, making it totally unobservable for several weeks while it is lost in the Sun's glare. At around the same time, Neptune will also be at its most distant from the Earth – receding to a distance of 30.93 AU – since the two planets will lie on opposite sides of the solar system. If Neptune could be observed at this time, it would appear at its smallest and faintest on account of its large distance. It would measure 2.2 arcsec in diameter. Over following weeks and months, Neptune 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.

March 9 – NGC 3532 well placed for observation. Across much of the world, the wishing well open star cluster (NGC 3532) in Carina will be well placed for observation. It will reach its highest point in the sky at around midnight local time. At a declination of -58°46', it is easiest to see from the southern hemisphere but cannot be seen from latitudes much north of 11°N. At magnitude 3.0, NGC3532 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.

March11 – Conjunction of the Moon and Mars -12:10 UTC. The Moon, 5 days old, and Mars will share the same right ascension, with the Moon passing 5°47' to the south of Mars. The Moon will be at mag -10.9, and Mars at mag 1.3, both in the constellation Aries. The pair will be too widely separated to fit within the field of view.

March 15 – Mercury at inferior solar conjunction – 01:42 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 3°29' 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 10.9 arcsec in diameter, whilst appearing completely unilluminated.

March 17 – Close approach of the Moon and M44 – 13:31 UTC. The Moon and M44 will make a close approach, passing within 0°09' of each other. The Moon will be 11 days old. The Moon will be at mag -12.6, and M44 at mag 3.1, both in the constellation Cancer. The pair will be close enough to fit within the field of view of a telescope, but will also be visible through a pair of binoculars.

March 18 – 69P/Taylor at perihelion. Comet 69P/Taylor will make its closest approach to the Sun, at a distance of 2.28 AU.

March 20 – March equinox – 21:44 UTC. The March equinox marks the first day of spring for anybody living in the northern hemisphere, and the first day of autumn for anybody living in the southern hemisphere. On the day of the equinox, everywhere on Earth has almost exactly 12 hours of day and night, as the Sun's annual journey through the constellations of the zodiac carries it across the celestial equator. The word equinox is derived from the Latin words aequus (equal) and nox (night) Wherever you live on Earth, on the day of the equinox the Sun will rise from the point on the horizon which lies due east, and set beneath the point which lies due west. Equinoxes occur because the axis of the Earth's spin – its polar axis – is tilted at an angle of 23.5° to the plane of its orbit around the Sun. The direction of the Earth's spin axis remains fixed in space as it circles around the Sun, while the Earth's sight line to the Sun moves through the constellations of the zodiac. As a result, sometimes the Earth's north pole is tilted towards the Sun (in June), and sometimes it is tilted away from it (in December).

March 21 – Full Moon – 01:44 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. This month's full moon will take place unusually close to the time of month when the Moon also makes its closest approach to the Earth – called its perigee. This means the moon will appear slightly larger and brighter than at other times, though any difference is imperceptible to the unaided eye. Perigee full moons such as this occur roughly once every 13 months. 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 spring 2019 – the Egg Moon. Over the nights following March 21, 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 +04°16' in the constellation Virgo, and so will appear high in the sky at all but the most extreme latitudes. It will be visible at all latitudes between 84°N and 75°S. Its distance from the Earth will be 360 000 km.

March 22 – Conjunction of Mercury and Neptune – 06:14 UTC. Mercury and Neptune will share the same right ascension, with Mercury passing 3°24' to the north of Neptune. Mercury will be at mag 2.8 in the constellation Pisces, and Neptune at mag 8.0 in the neighboring constellation of Aquarius. 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.

March 25 – 136472 Makemake at opposition – 19:59 UTC. 136472 Makemake will be well placed for observation, in the constellation Coma Berenices. It will be visible for much of the night, reaching its highest point in the sky at around midnight local time.

March 27 – Conjunction of the Moon and Jupiter – 02:28 UTC. The Moon, 21 days old, and Jupiter will share the same right ascension, with the Moon passing 1°53' to the north of Jupiter. At around the same time, the two objects will also make a close approach, technically called an appulse. The Moon will be at mag -12.1, and Jupiter at mag -2.2, 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.

March 27 – Close approach of the Moon and Jupiter – 02:54 UTC. The Moon and Jupiter will make a close approach, passing within 1°52' of each other. The Moon will be at mag -12.1, and Jupiter at mag -2.2, 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. At around the same time, the two objects will also share the same right ascension – called a conjunction.

March 29 – Conjunction of the Moon and Saturn – 05:00 UTC. The Moon and Saturn will share the same right ascension, with the Moon passing 0°03' to the south of Saturn. At around the same time, the two objects will also make a close approach, technically called an appulse. The Moon will be at mag -11.6, and Saturn at mag 0.4, both in the constellation Sagittarius. 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.

March 29 – Close approach of the Moon and Saturn – 05:00 UTC. The Moon and Saturn will make a close approach, passing within 0°03' of each other. The Moon will be at mag -11.6, and Saturn at mag 0.4, both in the constellation Sagittarius. 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. At around the same time, the two objects will also share the same right ascension – called a conjunction.

March 29 – Close approach of the Moon and Pluto – 11:39 UTC. The Moon and Pluto will make a close approach, passing within 0°18' of each other. The Moon will be at mag -11.5, and Pluto at mag 14.8, both in the constellation Sagittarius. The pair will be close enough to fit within the field of view of a telescope, but will also be visible through a pair of binoculars.

Video courtesy Hubble Space Telescope

Sources: In The Sky by Dominic Ford, NASA, TW

Featured image credit: NASA, TW