Instructions to read before looking up – January’s night sky
- Learn what is January and what we do with it,
- Find out what’s the Sun up to,
- What’s in the Milky Way, and what Orion, Scorpius and the Southern Cross — which are also in the Milky Way, are up to
- What are the brightest stars visible at night after sunset and finally
- Find out about our favourite binocular and telescope objects.
1-2-3, dogs and cats
From New Zealand we see the 1st, 2nd and 3rd (third) brightest stars in the sky. A Dog Star and a Cat Star are high up in the sky and also 2 Royal Stars. The Magellanic Clouds are in a good position to observe. Deep sky objects are amazing and Canopus is our favourite star this month while Orion is shining bright. And Janus, the deity that gave the name to January was more important than Jupiter to the Romans.
January was a recent addition to the Latin calendar, which only had 10 months until King Numa Pompilius instated it around 703 BC. Winter was considered by the Romans a month-less period as there was not much work to be done in wintertime about 3000 years ago. Until January was added, the year started with March.
The name comes from the god Janus, a mythical creature with two faces, looking simultaneously into the past and into the future, the God of Gates and Time, Births and Passages, and Endings. Wikipedia discusses the etymology of the word stemming from Proto-Italic *iānu (‘door’), ultimately from Proto-Indo-European *ieh₂nu (‘passage’) and being cognate with Sanskrit yāti (‘to go, travel’), Lithuanian jóti (‘to go, ride’), or Serbo-Croatian jàhati (‘to go’). (de Vaan, Michiel (2008). Etymological Dictionary of Latin and the other Italic Languages. Brill. ISBN 9789004167971; Taylor, Rabun, “Watching the Skies: Janus, Auspication, and the Shrine in the Roman Forum,” Memoirs of the American Academy in Rome vol. 45 (2000): p. 1)
An Uranic Deity
Accordingly, Iānus is translated as an action name expressing the idea of going, passing, formed on the root *yā- < *y-eð2– theme II of the root *ey- go from which eō, ειμι. Janus was also inspiration for all names that bear its resemblance: Jan, Jon, Joanne, Ion, Ioana, Iana, Diana, Iani and so on. Janus was an Uranic deity, associated with Uranus, the sky, as it was identified with light and hence the Sun, Moon, time, movement, the year, doorways and bridges, an extraordinary deity with a lot of responsibilities on his shoulders.
The temple of Janus in Rome was open during wartimes and closed when the empire was at peace. Probably the most important god of the Roman pantheon, Janus was at least as important as Jupiter. And maybe that is the reason why Numa Pompilius called January the first month of the year, as Janus was considered the highest divinity at the time.
The divine pillars
In ancient Summer, two pillars marked the summer and winter solstice on the eastern part of temples, these were symbolising two divine twins, one of whom was mortal, symbolised by the NE pillar where the Sun did not shine and the other immortal symbolised by the SE pillar where the Sun always shone. Later on in Egypt and Middle East the two columns morphed into one with two torsos and finally into one body with two heads looking in opposite directions. (Audin, A. (1956). “Dianus bifrons ou les deux stations solaires, piliers jumeaux et portiques solsticiaux”. Revue de géographie de Lyon. 31 (3): 191–198.) The divine twins are now the constellation of Gemini, which was high in the night sky 3000 years ago in January as seen from Rome and now is on the northeastern horizon at sunset as seen from New Zealand.
What’s the Sun up to?
In January, the Sun is at its closest distance to Earth. This is called perihelion and is due to the fact that Earth’s orbit around the Sun is an elliptical path.
Not only that we are closest to the Sun this time of the year but from the Southern Hemisphere Earth’s axis leans towards the Sun, hence is summertime.The Sun also rises really early in January. To catch the sunrise on the first day of January you’d have to wake up around 5:50AM (more or less a few minutes every year) but by the end of the month you can sleep almost half an hour more as the Sun rises around 6:25AM on the 31st of January. It sets very late, around 9PM at the beginning of the month and about twenty minutes earlier at the end of it.
Phases of the Moon
We tend to avoid the Moon for stargazing because it casts too much light.
The worst time to look at the Moon is when is full
Although we have filters for that that reduces the amount of light we receive from it, the worst time to look at the Moon is when is full.
The reason for that is the Moon casts too much light that breaks down the rhodopsin that formed in our eyes to help us see in the dark. When you look at the Moon through a telescope is almost as if someone turns on the light after you’ve been a while in a dark room. Not pleasant.
The Zodiacal Band
In January, the Sun first transits the zodiacal constellations of Sagittarius, and then moves into Capricorn on the 20th of January where it stays until February the 16th. The zodiacal constellations are those stars visible behind the plane of our solar system, about 8 degrees each side of the ecliptic. This is why we say they form a band in the sky, called the Zodiacal Band.
As the Earth goes around the Sun, our vantage point from where we are looking at the stars at night changes every so slightly. It’s really similar to how we see things when looking outside of a Mary Goes Round except that the Earth goes around the Sun in a year.
For the reasons of avoiding looking straight into the Sun we predict that Sagittarius and Capricorn will not be visible after sunset during January, even if you try really hard, because they are beyond the Sun. The light from the Sun washes out everything else during daytime, except for the Moon sometimes, so we are unable to see the stars.
However, you look on the opposite side to the setting Sun, Gemini the Divine Twins and then Cancer the Crab should be rising and since they are exactly in the opposite direction to the Sun, they should be visible all night long.
It’s dangerous to look into the Sun!! Of course, if you have solar telescope, that is well maintained and is designed for looking at the Sun, then you can look at the Sun.
Astrophotography comes in 3 flavours:
- landscape — which had a huge resurgence in the last 15 years with the advent of advanced digital cameras,
- deep sky — which is when you attach a camera to a telescope and
- planetary — that’s when you take pictures of objects within our solar system and this is a separate category because it requires different techniques than deep sky.
In January, Orion is the constellation that features in the night sky and you can get some amazing astrophotography shots with it. On the right hand side from Orion (that is east) you will see Sirius the dog on the left hand side you will see the closest cluster to Earth, the Hyades and to the left of that the famous Pleiades/M45 cluster.
The Milky Way flows like a river underneath Orion then disappears beyond the horizon through the Southern Cross. When we look at Orion we are looking towards the outskirts of the galaxy. It may seem that we see more stars in summer than in winter, especially if they twinkle a lot but we are really only seeing mostly our closest neighbour stars that are surrounding us in our bubble of space. Each side of the Milky Way, to the left of Orion are the two dogs: Sirius, the big dog and Procyon the small dog (or the hot dog), closer to the horizon.
On the ecliptic from east to west we can see the faint now zodiacal constellations of Gemini, Taurus, 3-starred Aries (literally, there are only 3 main prominent stars in Aries), Aquarius, with its dim stars that look like two big splashes of water and at the beginning of the month Capricornus is very close to the Sun.
Deep sky objects for astrophotography in January
Orion Nebula or M42 has some spectacular features so it’s the prime target. The Flame Nebula, close to one of the belt stars of Orion is a great target too, as it includes the famous Horse Head nebula. Then you got the clusters around Sirius, such as M41. On the circumpolar circle you have Tarantula Nebula, NGC 2516 cluster, for those more ambitious there is Topsy-Turvy Galaxy, 47 Tucanae or the lesser known NGC 362 globular cluster.
The Pleiades are a good wide field target as they will not fit in anything larger than 2 degrees across. The size of the Pleiades is 2 degrees, the width of 4 full Moons.
Circumpolar objects to New Zealand
What does circumpolar mean? Circumpolar are objects that rotate around the celestial pole. These objects are above the horizon at all times in a given latitude. For instance Cassiopeia is circumpolar from Europe but here in Wellington we cannot even see it, it’s hidden by the Earth. We could if Earth would have been transparent. Here on the other hand we have the Southern Cross with the pointers that are circumpolar. They turn around once in 23 hours and 56 minutes.
The Magellanic Clouds are in a good position to observe as they are high in the sky. Also the False Cross I relatively high so by 11PM you will start to see a good Eta Carina view and all the other clusters.
Two Royal Stars hang across the evening sky of January: Fomalhaut in Piscis Austrinus and Aldebaran in Taurus. According to French astronomer Camille Flammarion, the royal stars were the ancient guardians of the sky in ancient Persia where the sky was divided into four districts each guarded by one of the four Royal Stars.
From east to west, after sunset are: Aldebaran in Taurus, the stars of Orion (Rigel and Orion’s belt), Sirius and Adhara in Canis Major, Suhail al Muhlif in Vela, Avior and Miaplacidus in Carina, Crux and The Pointers, Alpha and Beta Centauri.