Earth reaches perihelion (closest to the Sun) on 3 January at 5.25 pm lying
some 147,099,895 km (0.983 AU) distant with the Sun in Sagittarius (The
Archer).
Daylight lengthens from 07:06 (7.093 hours) on 1 January to 08:34 (8.574 hours)
on 31 January so, post Winter Solstice, we lose 1 hour and 29 minutes of
night time by month’s end. This still gives us more than 16 hours of night-time
and 11–12 hours of astronomical dark time all month long. The Sun leaves
Sagittarius (The Archer) on 19 January at 5:34 pm and enters Capricornus (The
Sea Goat).
The Moon begins the month in Taurus (The Bull) and ends in Cancer (The Crab)
and recedes from Earth by 7,483 km. The first Lunar perigee (closest to Earth)
arrives on 1 January at 9:53 pm and finds the Moon some 360,361 km away from
Earth—around 24,039 km closer than average—subtending an angle of 33.2
arc-minutes. The full Wolf Moon makes an appearance on 3 January at 10:03 am in
Gemini (The Twins) and is also the first supermoon of the year. The Moon enters
last quarter on 10 January at 3:48 pm in Virgo (The Maiden). Lunar apogee
(furthest from Earth) that occurs on 13 January at 8:54 pm and takes the Moon
to 405,405 km away from Earth—around 21,005 km further than
average—subtending an angle of 29.5 arc-minutes. The new Moon appears on 18
January at 7:52 pm in Sagittarius (The Archer) beginning a new synodic month
which will last 29 days, 16 hours and 9 minutes. The first quarter Moon shows
up on 26 January at 4:47 am in Aries (The Ram). The second Lunar perigee
(closest to Earth) rounds out the month on 29 January at 9:56 pm with the Moon
365,894 km away from Earth—around 18,506 km closer than average—subtending
an angle of 32.6 arc-minutes.
The Moon conjuncts with some well-known stars throughout January: On 4 January,
Pollux in Gemini (The Twins) lies some 3 degrees north of the waning gibbous
Moon in the wee, small, hours. When it rises later the same day, it will
conjunct and occult the Beehive cluster (M44) in Cancer (The Crab). On 6
January, Regulus in Leo (The Lion) rises 0.5 degrees south of the still waning
gibbous Moon. On 11 January, Spica in Virgo (The Maiden) rises 1.5 degrees north
of the waning crescent Moon. Finally, on 27 January, the Pleiades open star
cluster lies 1.1 degrees south of the waxing gibbous Moon.
For the inferior planets: Mercury begins the month in Sagittarius (The Archer)
and ends in Capricorn (The Sea Goat) and approaches by 6,027,744 km (0.040 AU).
The ‘Swift Planet’ increases in magnitude from -0.56 to -1.27 (1.91 times in
brightness) over the month. Mercury reaches the first aphelion of the year on
6 January. It moves gradually towards the Sun until it reaches superior
conjunction (behind the Sun when viewed from Earth) on 21 January and is lost
for observing. Mercury will be at minimum separation (in km), all year, from
Venus on 22 January and Mars on 17 January.
Venus begins the month in Sagittarius (The Archer) and ends in Capricorn (The
Sea Goat) and approaches by 1,521,984 km (0.010 AU). This minuscule change in
distance, astronomically speaking, allows Venus to maintain a bright -3.9
magnitudes. That said, Venus reaches superior conjunction on 6 January and
becomes unobservable. Aphelion occurs on 22 January. Venus will be at maximum
distance from Earth all year at 255,955,658 km on 8 January. Conversely, the
‘Morning Star Planet’ will be closest (in km) to Mars all year on 10 January.
For the superior planets: Mars begins the month in Sagittarius (The Archer) and
ends in Capricorn (The Sea Goat) and approaches by 4,777,486 km (0.032 AU).
This barely affects the magnitude of 1.12 magnitudes. The ‘Red Planet’ does
reach solar conjunction on 9 January. Mars and Jupiter are at maximum
separation (in km) on 3 January.
Jupiter remains in Gemini (The Twins) all month but recedes by 10,399,109 km
(0.070 AU). Jupiter decreases, very slightly, in magnitude from -2.67 to -2.62
(1.05 times in brightness) over the month. The ‘Gas Giant’ planet conjuncts
with the Moon on 3 January and 31 January being 3.75 degrees south of the Moon on
average. On 9 January, Jupiter is closest to Earth all year and on 10 January
reaches opposition. This is the best opportunity to see the dazzling, bright,
planet in the Edinburgh and Lothian evening sky. If the tables were turned and
you were a Jovian dweller, you would witness a transit of Earth and Moon
(across the face of the Sun) on 10 January that would take 5 hours from start
to finish!
Saturn begins the month in Aquarius (The Water Bearer) and ends in Pisces (The
Fishes) but recedes by 66,478,246 km (0.444 AU). Saturn decreases in magnitude
from 1.00 to 1.03 (1.02 times in brightness) over the month.
The Quadrantids meteor shower will peak on 3 January. The parent body is
asteroid 2003 EH1 which orbits the Sun with a 5.5 year period. The radiant
point is between the stars Edasich in Draco (The Dragon) and Nekkar in
Bootes (The Herdsman) and both are labelled on our skymap. Expect, possibly,
80 meteors per hour but, of course, the supermoon is full hampering decent
viewing. The shower was named after the constellation Quadrans Muralis
(The Mural Quadrant) but this was dropped by the IAU in 1922. The shower name,
however, was not changed although, in the modern era, it is also referred to as
the Bootids. The gamma-Ursae Minorids peak on 18 January with a low ZHR
of 3 but there is no moon so may be worth a punt as they are circumpolar.
At the time of our sky map, some constellations visible are Camelopardalis (The
Giraffe) and Auriga (The Charioteer) at zenith, Draco (The Dragon) in the
north, Lynx (The Lynx) in the east, Andromeda (The Chained Maiden) in the west,
and Orion (The Hunter) in the south. The ecliptic hosts Leo (The Lion), Cancer
(the Crab), Gemini (The Twins), Taurus (The Bull), Aries (The Ram) and Pisces
(The Fishes).
Orion (The Hunter) is a glorious sight in January and serves as a pointer to
other constellations and formations. At the time of our sky map, follow the
belt upwards to intersect Aldebaran, the red eye of Taurus (the Bull) and the
Pleiades (M45 or Seven Sisters) open star cluster. Follow the belt downwards to
the night sky’s brightest star, Sirius in Canis Major (The Great Dog). The red
giant Betelgeuse in Orion forms a pseudo-constellation with Sirius and Procyon
in Canis Minor (The Lesser Dog) called the ‘Winter Triangle’. Similarly, the
stars Rigel, Sirius, Procyon, Pollux in Gemini (The Twins), Capella in Auriga
(The Charioteer) and Aldebaran for the pseudo-constellation known as the
‘Winter Hexagon’ and cover a very large area of sky. From these 7 stars it is
possible to identify many other constellations. Circumpolar
constellations—always above the horizon—include Cepheus (The King), Perseus
(The Hero), Cassiopeia (The Seated Queen) and Ursa Major (The Greater Bear).
