Categories: Observing

The Night Sky This Month: January 2018

Image Credit: Super Moon vs. Micro Moon by Catalin Paduraru

Happy 2018! January presents a perfect opportunity to view some of the winter sky’s most conspicuous constellations, including Orion accompanied by his two hunting dogs Canis Major and Canis Minor. The giant hunter from Greek mythology can be seen battling the huge celestial bull represented by Taurus to his west, while his hounds pursue Lepus the hare eastwards through the sky. Other prominent nearby constellations includes Eridanus, Gemini, Cetus, and Perseus, while another group of constellations, including Ursa Major, Ursa Minor, Cassiopeia, Cepheus and Draco are northern circumpolar and so are always visible throughout the year.


The image above shows a super moon alongside a micro moon that occurred during 2012. Lunar observers now have the opportunity to observe such a super moon again during January 2018, as well as a Blue Moon, or a second full moon within one calendar month. Super moons occur when the Moon is closest to Earth, which will occur on the 31st of January 2018 when the centers of the Moon and the Earth will be 358,994 km (9223,068 miles) apart. Before that, though, the first full moon of January 2018 will be visible at 2:24 AM (local time) in the UK, on New Years’ Day.

To top that, much of the globe will be treated to a lunar eclipse on the last day of the month. Sadly, it occurs on the last day of January 2018 when the second full Moon also occurs, and so it will therefore not be visible to observers in the UK, although it can be seen to varying degrees in North America, much of the Pacific Region, Australia, New Zealand, and much of Asia. The next lunar eclipse, albeit a partial eclipse, will only be visible from the UK towards the end of July 2018.


Full Moon: 2nd
Last Quarter: 8th
New Moon: 17th
First Quarter: 24th
Full Moon: 31st

Provided seeing conditions allow, lunar observers should see significant earthshine illuminating the waxing crescent Moon from 18th to the 23rd of January, and again from the 9th to the 26th of the month, when light reflected off the Earth will illuminate the waning crescent Moon.

The Planets

Mercury is still visible in the predawn sky, and will reach its maximum elongation from the Sun on the 1st of January, when it will be 23 degrees to the west of the Sun. During the first two weeks of the month, the little planet rises about two hours before dawn, and provided seeing conditions allow, it will be visible with binoculars low above the south-eastern horizon from about an hour or so before dawn.

Venus reaches a position of superior conjunction with the Sun on the 9th, and will therefore not be visible during the entire month of January.

Mars will increase in brightness throughout the month as it moves eastwards through the constellation Libra, and by the middle of the month the red planet will shine at about magnitude +1.3. In the early morning of the 11th, the waxing crescent Moon will join Mars and Jupiter in a close pairing, with the Moon about 4 degrees above the two planets.

Jupiter still dominates the early morning sky, and rises at about 04:00 in the constellation Libra as January starts, but it will appear progressively earlier, to rise at about 02:00 by month’s end. For most observers in the UK, Jupiter will reach an elevation of about 20 degrees when it is due south. Mars will approach Jupiter during the first days of January, and will overtake the King of the planets on the 7th when the two planets will be less than 0.25 of a degree apart, with Mars just below Jupiter.

Saturn rises two hours before dawn in the constellation Sagittarius at month’s end, at which time it will shine at magnitude 0.5 low above the south-eastern horizon. Although this is not a good time to view the ringed planet, it can be found relatively easily with binoculars about one hour before dawn during the last two weeks of January. On the 13th, Saturn will form a close pairing with the planet Mercury, with Saturn separated from the slightly brighter Mercury by less than one degree. Look for the pair of planets low on the south-eastern horizon at about 07:30. On the 14th, the thin waning crescent Moon will approach the grouping before dawn.

Uranus is now an evening object shining at about magnitude +5.8. Look for the planet about 3.5 degrees to the westward of the 4.2 magnitude star Trocularis Septentri (omicron Piscium), but note that by the end of the month, Neptune will set at about midnight.

Neptune is presently in the constellation Aquarius, and sets at about 07:00 PM as January starts. However, by month’s end, it will set about two hours later and although it is visible in medium sized telescopes, it is significantly dimmer than Uranus and may be difficult to spot. Nonetheless, if seeing conditions permit, Neptune can be found about one Moon-width towards the lower right of the 3.74 magnitude star, lambda Aquarii (73 Aquarii).

Meteor Showers

The Quadrantids is the only meteor shower visible during January 2018, and has its radiant in the northern reaches of the constellation Boötes, and just to the left of the “handle” of the Big Dipper (The Plough). The shower derives from the remains of the erstwhile asteroid 2003 EH1, which was destroyed about 500 years ago.

Note that although a maximum zenithal hourly rate of more than 80 meteors per hour is expected during its peak on the 3rd, the Moon will be full on the 2nd, which is bound to hamper seeing conditions. However, since the Quadrantids has a broad peak that runs from the 1st to the 6th, it might be possible to see at least some meteors from this shower on dates on both sides of the expected peak date.

Deep-Sky Objects

Below are some details on a few deep-sky objects (DSOs) that can easily be found with modest amateur equipment in three northern winter constellations:

Image Credit: Friendlystar at wikipedia.org

– NGC 2371-2, located in Gemini, is a planetary nebula that looks like it could have been two distinctly individual objects, which is why it still has two separate NGC designations, NGC 2371 and NGC 2372. This pretty nebula is about 4,400 light years away and has an apparent visual magnitude of 13.0, which makes it an easy target for medium sized amateur telescopes. As a point of interest, NGC 2371-2 is included in the Royal Astronomical Society of Canada’s (RASC) Finest NGC Objects list. Look for this nebula to the south-westward of the bright star Castor.

– NGC 1333 is a large (6’x3′) reflection nebula located in the constellation Perseus, but more precisely, in the Perseus Molecular Cloud, which is an enormous star forming region. Located about 1,000 light years away, the nebula has an apparent visual magnitude of 5.6.

The Hyades Cluster (Caldwell 41, Melotte 25, Collinder 50) is an open cluster consisting of several hundred stars that share a common proper motion across the sky. Their almost identical chemical compositions suggest a common origin for all the stars in the cluster, except for Aldebaran, which is not an actual member of the cluster, since it only lies along the same line of sight towards the cluster. The four brightest stars in the cluster, Gamma, Delta, Epsilon, and Theta Tauri are all highly evolved red giant stars that are placed within a few light years of each other, and collectively, these four stars form the prominent V-shaped asterism that delineates the bull’s head. At only 153 light years away, the Hyades is the closest open star cluster to Earth, and consequently it is the most intensely cluster studied by astronomers and imaged by professionals and amateurs alike.

Peter Christoforou :