January 2020

Welcome to SkyEye, your guide to this month's celestial events.

The Calendar

Three of the five bright planets are too close to the Sun to observe at the outset of 2020 but Venus dominates the western sky at sunset whilst fainter Mars is visible before dawn. The Moon undergoes four penumbral lunar eclipses this year, the first one on 10 January.

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Date Body Event
1 Saturn maximum ring opening: 23.6°
2 Moon apogee
Mercury, Jupiter conjunction: 1.5° apart
3 Moon first quarter
4 Earth Quadrantid meteor shower
5 Earth perihelion
9 Uranus maxiumum declination south
Moon ascending node
10 Mercury superior conjunction
Earth, Moon penumbral lunar eclipse
Moon full
11 Uranus stationary point: retrograde → direct
Moon 1.0° north of the open star cluster M44 (known as Praesepe or the Beehive Cluster)
12 Mercury, Saturn conjunction: 2.0° apart
13 134340 Pluto conjunction
Saturn conjunction: anti-transit
1 Ceres conjunction
Moon perigee
17 Moon last quarter
20 Moon, Mars 2.3° apart
22 Moon descending node
23 Moon, Jupiter occultation of Jupiter — visible from Madagascar
Uranus east quadrature
24 Moon, Saturn 1.4° apart
Moon new
25 Moon, Mercury 1.3° apart
27 Venus, Neptune conjunction: 0.1° apart
29 Moon apogee

The Solar System

The word planet is derived from the Greek word for 'wanderer'. Unlike the background stars, planets seem to move around the sky, keeping mostly to a narrow track called the ecliptic, the path of the Sun across the stars. Dwarf planets and small solar-system bodies, including comets, are not so constrained, often moving far above or below the ecliptic.

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Sun SagittariusCapricornus

Mercury SagittariusCapricornus

Mercury is briefly a morning sky object but is low to the horizon at the beginning of the year and soon disappears from view. It undergoes superior conjunction on 10 January and reappears in the west after sunset late in the month. The nearly new Moon passes close by the tiny planet on 25 January.

Venus CapricornusAquarius

Venus ushers in the new year as the evening star. This apparition favours northern latitudes; although the planet is fairly low at this time, it will climb much higher over the next two months. However, observers in the southern hemisphere will not see Venus any higher in the west than it is now. Venus passes within 0.1° of Neptune on 27 January but a telescope will be required to spot the dim outer planet.

Earth and Moon

Perihelion and the Quadrantids always occur around the same time of year. In 2020, perihelion takes place on 5 January when Earth is 0.9832 au away from the Sun. As for the Quadrantid meteor shower which peaks the day before, the waxing gibbous Moon sets around midnight, leaving dark skies in the early morning hours. On 10 January, the Moon dips into Earth's penumbra, leading to a penumbral lunar eclipse, the first of four this year. Later, on 23 January, the waning crescent Moon occults Jupiter.

Mars LibraScorpiusOphiuchus

The red planet is a morning sky object this month, rising an hour or so before the sky starts to brighten. The waning crescent Moon pays a visit on 20 January, coming within almost 2° of the planet. Mars is over 2 au away from Earth and shines at around magnitude +1.5.

Jupiter Sagittarius

Jupiter was at conjunction late last month so it is not visible during early January. However, it eventually appears in the morning sky ahead of the Sun and is occulted by waning crescent Moon on 23 January. This event begins just after midnight UT and is visible from Madagascar.

Saturn Sagittarius

The ringed planet is at conjunction on 13 January, actually passing behind the disk of the Sun as seen from Earth. This phenomenon is sometimes referred to as an anti-transit or secondary eclipse. Because it is so close to the Sun mid-month, Saturn is largely unobservable in January but appears in the east before sunrise next month.

Uranus Aries

Uranus enters the year backwards, moving in retrograde motion across the sky. However, it reaches a stationary point on 11 January and resumes direct motion. Two days before that, the distant green planet reaches its maximum declination south for the year (+11.8°). On 23 January, Uranus reaches quadrature, the point where it is 90° away from the Sun as seen from Earth. Look for this sixth-magnitude object in the evening after the skies are dark.

Neptune Aquarius

A small telescope is necessary to view the most distant planet in the solar system. Like its neighbour Uranus, Neptune is an evening sky object and sets before midnight. On 27 January, Neptune is found in close proximity with brilliant Venus, with the two objects less than 0.1° apart. However, only Venus is visible to the naked eye.

The Celestial Sphere

Constellations are patterns of stars in the sky. The International Astronomical Union recognises 88 different constellations. The brightest stars as seen from the Earth are easy to spot but do you know their proper names? With a set of binoculars you can look for fainter objects such as nebulae and galaxies and star clusters or some of the closest stars to the Sun.

Descriptions of the sky for observers in both the northern and southern hemispheres are available for the following times this month. Subtract one hour from your local time if summer (daylight savings) time is in effect.

Local Time Mid-month Northern Hemisphere Equator Southern Hemisphere
1730 hours (1830 hours summer time) 60° N 50° N 40° N 30° N 20° N 10° N 10° S 20° S 30° S 40° S
1930 hours (2030 hours summer time) 60° N 50° N 40° N 30° N 20° N 10° N 10° S 20° S 30° S 40° S
2130 hours (2230 hours summer time) 60° N 50° N 40° N 30° N 20° N 10° N 10° S 20° S 30° S 40° S
2330 hours (0030 hours summer time) 60° N 50° N 40° N 30° N 20° N 10° N 10° S 20° S 30° S 40° S
0130 hours (0230 hours summer time) 60° N 50° N 40° N 30° N 20° N 10° N 10° S 20° S 30° S 40° S
0330 hours (0430 hours summer time) 60° N 50° N 40° N 30° N 20° N 10° N 10° S 20° S 30° S 40° S
0530 hours (0630 hours summer time) 60° N 50° N 40° N 30° N 20° N 10° N 10° S 20° S 30° S 40° S