The Planets this Month - January 2016

Mercury

Mercury the nearest planet to the Sun is visible as both an evening and morning object during January. The small elusive planet can be seen for the first few days of the month low down above the southwestern horizon after sunset (mag. -0.3). During this time it's slightly easier to spot Mercury from tropical and southern locations. However it doesn't take long before the fading planet draws into the Sun and is lost to the bright twilight glare.

On January 14th, Mercury passes through inferior conjunction. Subsequently it re-appears in the morning sky and may be seen towards month's end low down above the ESE horizon, 45 minutes before sunrise (mag. +0.0). Much brighter Venus (mag. -3.9) is positioned 7 degrees west of Mercury.

Venus

Venus is now fading in brightness but continues to be visible as a brilliant morning object before sunrise towards the southeast (Northern Hemisphere) / east-southeast (Southern Hemisphere). The planet starts the month at magnitude -4.1, ending it at magnitude -3.9. Although now limbering towards the lower end of its brightness range it remains unmistakable, a dazzling beacon of light hovering above the horizon.

At the start of January, Venus rises up to 3 hours before the Sun although from northern temperate latitudes the visibility period shortens considerably as the month progresses. By the end of January it reduces to just over an hour. From Southern Hemisphere and equatorial regions it still rises up to 2.5 hours before the Sun at months end.

On January 6th, Venus passes 6 degrees north of red supergiant Antares (α Sco - mag. +1.0). The following day the thin 10% illuminated waning crescent Moon forms a nice pairing with Venus. Finally on January 9th, Venus makes a close pass north of Saturn (mag. +0.6). The minimum separation of 5 arc minutes is equivalent to only 1/6 the apparent diameter of the Moon. Venus acts as a useful guide in locating the much more distant and fainter Saturn.

The phase of Venus increases from 77 to 85% as the month progresses.

Venus and Saturn during January 2016 (credit:- freestarcharts)

Earth

Earth reaches perihelion or closest point to the Sun on January 2nd at a distance of 147.1 million kilometres (91.4 million miles).

Mars

Mars begins the New Year in Virgo as a mag. +1.2 morning object rising between 2am and 3am local time from northern temperate latitudes but rather earlier from locations further south. As the month progresses the planet brightens to mag. +0.8 with its apparent size increasing from 5.6 to 6.8 arc seconds.

This year promises to be a great year for "Red planet" watchers with the highlight occurring on May 22nd when opposition is reached. On this day Mars will shine at magnitude -2.1 and therefore easily brighter than all of the night time stars. Its apparent size will be a healthy 18 arc seconds. In addition there is no hiding of Mars this year, for the whole of 2016 it will be at some time of the night always visible.

The waning crescent Moon passes 1.5 degrees south of Mars on January 3rd.

Mars during January 2016 - pdf format (credit:- freestarcharts)

Jupiter

Jupiter is located in Leo and continues to increase in brightness and apparent size as it heads towards opposition in March. The Solar System's largest and dominant planet is a brilliant morning object that rises before midnight at the start of January, improving by a couple of hours by months end.

Binoculars will reveal the off white or creamy coloured disk of Jupiter but without detail. Also visible are the four large Galilean moons (Io, Europa, Ganymede and Callisto). They continuously change position as they orbit the planet. Sometimes all four are visible at once but on occasions some satellites will be hidden from view as they pass in front of or behind the giant planet's disk.

This month Jupiter brightens from magnitude -2.2 to -2.4 and it's apparent size increases from 39 to 42 arc seconds. On January 8th, it reaches its first stationary point which signals the start of the 2016 opposition period. Afterwards the planet commences retrograde motion.

The waning gibbous Moon passes 1.4 degrees south of Jupiter on January 28th.

Jupiter during January 2016 - pdf format (credit:- freestarcharts)

Saturn

Saturn, mag. +0.6, is now an early morning object moving direct amongst the stars of Ophiuchus. With a declination of 20 degrees south the beautiful ringed planet is currently better seen from southern and tropical latitudes where it rises 2 hours before the Sun at the start of the month. The visibility period increases as January progresses with the planet visible a couple of hours after midnight by months end. For northern temperate based observers the visibility of Saturn is not quite as good.

Through a telescope Saturn's most famous feature are of course its spectacular rings and even a small telescope will show them. They are currently displayed wide open with a 26 degree tilt. In addition small scopes will also show the brightest Moons including Titan, Rhea, Tethys and Dione.

The thin waning crescent Moon passes 3 degrees north of Saturn on January 7th. As previously noted on January 9th brilliant Venus (mag. -4.0) moves just 5 arc minutes north of Saturn.

Uranus

Uranus is moving direct in Pisces southeast of the "Great Square of Pegasus" and 2 degrees south of mag. +4.3 star epsilon (ε) Psc. The distant cold ice giant is visible during the first half of the night, now setting around midnight. At magnitude +5.9 it can just be seen with the naked eye but dark Moonless skies away from light pollution are required. For most observers this is seldom the case and binoculars or a small telescope are needed to spot the seventh planet from the Sun.

Any quality made telescope at high powers will show the disk of Uranus, which appears green in colour and has an diameter of 3.5 arc seconds. The small apparent size means spotting any surface details is difficult even with the largest of amateur scopes.

On January 16th, the first quarter Moon passes 1.5 degrees north of Uranus.

Uranus during January 2016 - pdf format (credit:- freestarcharts)

Neptune

Neptune, mag. +8.0, is an early evening object located in Aquarius that's visible above the western horizon for a short time as soon as it's dark enough. As January progresses Neptune will become more difficult to spot as it battles against the bright twilight sky. This month also offers the last realistic chance to catch a glimpse of the most distant planet in the Solar System before it reaches solar conjunction next month.

Neptune is positioned 30 degrees southwest of the "Great Square of Pegasus" and two degrees northeast of sigma Aqr (σ Aqr - mag. +4.8). The planet varies little in brightness from our perspective and even at opposition it's not bright enough to be seen with the naked eye but can be spotted with binoculars and small scopes.

The waxing crescent Moon passes 2 degrees north of Neptune on January 13th.

Neptune during January 2016 - pdf format (credit:- freestarcharts)

Solar System Data Table January 2016