January 2021 — Night Sky Guide & Key Dates

As another year draws to a close, here at Astronomy Trek we would like to wish all our readers out there a very happy and healthy 2021!

January also offers a great chance to observe some of the winter sky’s most conspicuous constellations. This, of course, includes the giant Orion and his two hunting dogs, as well as northern circumpolar constellations such as Ursa Major, Ursa Minor, Cassiopeia, and Cepheus.

Other astronomical phenomena to look forward to includes the Quadrantid meteor shower, and an apparent close approach between Mars, the Moon and Uranus. So without further ado, let’s explore some of the delights that await in the January 2021 night sky.

The Moon in January 2021

The year 2021 sees three Super Moons- on April 27th, May 26th, and June 24th. Note that the Super Moon on May 26th coincides with a total lunar eclipse, which will be visible for observers throughout the Pacific Ocean, large parts of eastern Asia, Australia, Japan, and much of western North America.

Moon phases

Last Quarter New Moon First Quarter Full Moon
January 6th January 13th January 20th January 28th

The Planets in January 2021

Planetary viewing will be extremely poor during most of January, but observers that are up for a challenge can expect the following:

Mercury reaches its point of greatest eastern elongation from the Sun on January 23rd, at which time it will be 18.6 degrees east of the Sun. However, while the little planet will then be at its highest point above the western horizon, it will still be very low. Nonetheless, the planet sets about 90 minutes after the Sun, which should make it possible to get some satisfactory views of the little planet from mid-northern latitudes.

Venus starts the month rising only about 90 minutes or so before dawn, and will rise progressively later until, by month’s end, it will rise no more than about 35 minutes before dawn as seen from mid-northern latitudes. As a result, it might be very difficult to spot the planet as it rises into the brightening sky.

Mars is the only bright planet visible throughout January. However, the Red Planet will set at about midnight, and while it will be relatively bright during January, it is now moving away from Earth and it will therefore dim visibly over the next few months.

Jupiter and Saturn will remain relatively close to each other during January but note that both planets will descend to below the horizon for most northern observers during the second half of the month. Nonetheless, both planets will form a close planetary trio with Mercury on the 9th, 10th, and 11th of the month, with all three planets fitting into a circle with a diameter of about 2.4 degrees.

Note though that during the first half of the month, both Jupiter and Saturn will set about 90 minutes after the Sun. This time subsequently reduces to only 30 minutes or so by the end of the second week of January, after which time the planets will not be observable until they reappear from behind the Sun as early morning objects.

Meteor Showers in January 2021

The Quadrantids meteor shower typically runs from January 1st to about January 5th, with the peak expected to occur on the night of January 2nd/3rd.

This meteor shower is generally very productive and although light from the waning gibbous Moon might obtrude somewhat this year, observers in dark locations can expect to see a maximum of up to about 40 or so meteors per hour during the peak after midnight.  While the radiant of this shower is located in the constellation Boötes, meteors can appear to come from all points in the sky.

Deep Sky Objects to Look For in January 2021

Constellations that are prominent in the early evening sky at this time of the year include Lyra, Cygnus, Aquila, Cassiopeia, and Perseus. Orion, Taurus, Auriga, and Gemini rise somewhat later, and all should be fully visible from mid-northern latitudes after about midnight or so.

Weather and seeing conditions permitting, all of these constellations host a large variety of spectacular deep-sky objects that are visible with large binoculars or medium telescopes, some of which are discussed briefly below:

The Flaming Star Nebula (IC 405)

 The Flaming Star Nebula
Image credit: NASA / APOD

Located about 1,500 light-years away in the constellation Auriga, the magnitude 6.0 Flaming Star Nebula is both an emission and reflection nebula. The nebula emits radiation from the embedded star AE Aurigae while it reflects radiation from the nearby open star clusters Messier 36 and Messier 38, as well as from the star Iota Aurigae, and the emission nebula IC 410.

Look for this spectacular nebula that stretches across about 5 light-years at coordinates RA 05h 16.2m / Dec +34° 28′.

Messier 52 (NGC 7654)

Messier 52
Image credit: freestarcharts.com

Located about 5,000 light-years away in the constellation Cassiopeia, this magnitude 5.0 open cluster is visible as a faint, fuzzy patch of light in binoculars, but a small to medium telescope at low power will resolve individual stars. The two brightest stars in the cluster are old, yellow giants with magnitudes of 7.77 and 8.22, respectively. Note, though, that the two bright yellow objects in this frame are overexposed and unrelated foreground stars, as is evidenced by the diffraction spikes on them.

Messier 56 (M56, NGC 6779)

Messier 56
Image credit: NASA / Hubble Space Telescope

Located about 33,000 light-years away in the constellation Lyra, this magnitude 8.3 globular cluster spans across about 84 light-years. The cluster is around 13.7 billion years old and is about 230,000 times as massive as the Sun.

While large binoculars might show the cluster as faint blob of light, telescopes with larger apertures than 200 mm will resolve individual stars in the cluster that somewhat oddly, follows a retrograde orbit around the galactic core. One other noteworthy aspect of this cluster is that it is moving at a velocity of roughly 177 km/sec, which is fast enough to heat the medium it is moving through to a temperature of at least 940,000K.

UGC 1810 and UGC 1813

UGC 1810 and UGC 1813
Image credit: HST / NASA / ESA

UGC 1810 and UGC 1813 are a pair of interacting galaxies in the Andromeda constellation. While the larger galaxy, designated UGC 1810, might appear to be distorted by the interaction, it is, in fact, an almost perfect spiral galaxy whose outer regions are partly obscured by dark dust clouds. The active star-forming regions that are visible outside of the dust clouds are the result of a long-term gravitational tug-of-war with the less massive galaxy, designated UGC 1813, shown at the bottom of the frame.

According to the best estimates, the interaction will last for at least another 1 billion years, at the end of which the smaller galaxy will be fully assimilated into the spiral structure of the larger galaxy. The three bright objects in this image are bright foreground stars that are exhibiting pronounced diffraction spikes caused by parts of the Hubble Telescopes’ support structures.

Summary of key dates for January 2021 night sky

January 2: Earth is in Perihelion

Our orbit around the Sun is not perfectly circular, therefore once a year we end up in the closest point to the Sun (perihelion) and the furthest (aphelion). On this day the Earth will be at the closest point to the Sun, at a distance of 0.983 AU. This small difference of 2% results in 3.5% more sunlight!

January 3: The Quadrantid meteor shower

The new year will not just be celebrated with fireworks, as the Quadrantid will rain down on us. They originate a bit to the left from the big dipper and will generally be seen low around the horizon. However, this is made up by their activity, which peaks around 130 meteors per hour!

Remember that this is just the peak of the shower, so you can try days around this date if the weather is not cooperative, although the activity will go down. The Quadrantid are sharply peaked though, so the activity goes down a lot the days before and after.

January 21: Close approach Mars, Moon and Uranus

On this day the Moon will make a close approach to two of our planets. For novice observers this is a great opportunity to find Mars and those with a telescope or even binoculars can try to spot Uranus. The closest approach happens at 16:54 GMT, where all three are within 5 degrees of each other. The Moon will only be 8 days old at this point.

January 28: Wolf Moon

This is the first full Moon of the year, colloquially called the ‘Wolf Moon’. The name stems from old farmers almanacs and simply is a different way of saying ‘the first full moon in January.’

January 29: Mercury furthest away from Sun

If you want to spot Mercury, doing it around this day would be a great opportunity, as this is when the planet is situated furthest away from the Sun. This means that if you look west just after sunset, you should be able to see Mercury about 12 degrees above the horizon. It will be very bright, so easily spotable by eye. Look for something that looks like a plane, but does not blink.

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