Events During January
is at perihelion (147 million kilometres - its closest to the Sun)
3rd-4th: QUADRANTIDS METEOR SHOWER
is visible from the 1st to the 6th January,
at maximum on the 3rd/4th. The show will be spoilt by the Moon rising at
The average hourly rate can range from 10 to 120, with the radiant low in the north
during evening time.
6th - in the morning sky, the Moon is below Spica
7th - the Moon passes below Saturn in the morning sky
10th - Moon at Perigee (360,045 kms)
10th - before dawn the slender crescent Moon makes a striking pair with Venus
13th - the waxing crescent Moon moves above Mars
21st/22nd - the Moon passes a degree below Jupiter with Aldebaran to the left
22nd - Moon at Apogee (405,310 kms)
28th - the Moon is close to Regulus
Type: Terrestrial, Distance from Sun: 47 million kilometres to 70 million
kilometres at aphelion
Orbit Around Sun (Equatorial Rotation): 88 days Polar Rotation: 59 days
Temperature: -183 degrees C to 467 degrees C Atmosphere: Hydrogen, Helium
Diameter: 4,876 kilometres (3,030 miles) Mass: 5% of Earth
Inclination of Axis: 0 degrees Number Of Moons: 0 Rings: No
On January 18th MERCURY passes through superior conjunction on the far side of the Sun and is consequently
too close to the Sun to be seen this month.
The best times to observe Mercury in the northen hemisphere are when it is an evening star in the spring and a morning star in the autumn. In midsummer
the lighter skies make visibility difficult near the horizon.
Type: Terrestrial, Distance from Sun: 107 million kilometres (67 million miles)
Orbit Around Sun (Equatorial Rotation): 224.7 days Polar Rotation: 243 days
Temperature: 449 degrees C Atmosphere: Carbon Dioxide, Nitrogen
Diameter: 12,107 kilometres (7,523 miles) Mass: 81% of Earth
Inclination of Axis: 177.4 degrees Number Of Moons: 0 Rings: No
Just before sunrise, you can catch VENUS at a still brilliant magnitude -3.8, low in the south-east. At the beginning of January its rising one-and-a-half hours
before the Sun but, by the end of the month the planet's elongation has decreased so that it is too
close to the Sun to be visible.
On the 8th June 2004 and 5th/6th June 2012, Venus was at inferior conjunction
and transited the Sun. Transits of Venus are rare, taking place at greater
than 100 year intervals and usually in pairs. Prior to the recent events, the last transits of Venus were in 1874 and 1882. The next transits of Venus won't occur
again until 2117 and 2125.
Before and after inferior conjuction, when Venus is
the closest it comes to the Earth, are the times at which the planet is most brilliant and can be seen setting or rising
4 hours after or before the Sun. The last inferior conjunction was on June 5th/6th 2012.
Type: Terrestrial, Distance from Sun: 150 million kilometres (93 million miles)
Orbit Around Sun (Equatorial Rotation): 365.3 days Polar Rotation: 23 hours 56 minutes
Temperature: 7.2 degrees C Atmosphere: Nitrogen, Oxygen, Argon
Diameter: 12,755 kilometres (7,926 miles) Mass: 100%
Inclination of Axis: 23.45 degrees Number Of Moons: 1 Rings: No
Type: Terrestrial, Distance from Sun: 229 million kilometres (142 million miles)
Orbit Around Sun (Equatorial Rotation): 686.98 days Polar Rotation: 24.63 days
Temperature: -123 degrees C to 36 degrees C Atmosphere: Carbon Dioxide, Nitrogen, Argon
Diameter: 12,755 kilometres (7,926 miles) Mass: 10% of Earth
Inclination of Axis: 23.98 degrees Number Of Moons: 2 Rings: No
MARS, at magnitude +1.2, moves from Capricorn into Aquarius
during January and is inconveniently low in the south-western sky, setting just two hours after the Sun.
At opposition on the 28th August 2003, Mars was only 56 million kilometres from the Earth. It showed a
disc of 25.1 seconds of arc across which is almost as large as it can ever appear. Mars started 2003 at 310 million kilometres from
the earth at 4.5 seconds of arc and 1.6 magnitude. By opposition it brightened 50 times to reach -2.9 magnitude but faded to 0
magnitude by December. Even to the naked eye Mars was a striking object in the summer and autumn sky, easily identifiable by its
reddish hue in an area of sky poor in bright stars. Mars will not be as close again until 2018.
These favourable oppositions occur every 15 or 17 years but other oppositions occur at average intervals of 2 years 2 months during
which time the planet makes a complete circle of the Earth. In general Mars is observable every other year, being too close to the sun for favourable conditions
during other times. Brightness at opposition varies from -1.0 to -2.9 magnitude, and when furthest from the earth it fades to 1.7 magnitude. The planet can be
identified by its orange-red colour.
As in 2003, Mars comes nearest to the Earth at oppositions at the end of August. At these times it can be brighter than Jupiter,
although low in the sky in Aquarius for northern observors. In the northern hemisphere, the planet may be better seen at oppostions during autumn and winter months
when it is higher in the sky.
Type: Gas Giant, Distance from Sun: 777 million kilometres (483 million miles)
Orbit Around Sun (Equatorial Rotation): 4,333 days Polar Rotation: 9 hours 55 minutes
Temperature: -153 degrees C Atmosphere: Hydrogen, Helium, Methane
Diameter: 142,983 kilometres (88,846 miles) Mass: 318 x Earth
Inclination of Axis: 3.08 degrees Number Of Moons: 63 Rings: Yes
JUPITER was at opposition in early December and is still visible for most of the night. At magnitude -2.5,
it outshines any of the stars and its northerly declination means observors in the northern hemisphere have the best view. Jupiter contnues to move
retrograde in Taurus
until the end of the month when it reaches its second stationary point then resumes direct motion.
After spending the past six years in the southern skies, Jupiter moved north of the celestial equator on February 5th 2011 to spend the next six years
in northern skies.
Varying from 603 (at its closest) to 770 million kilometres from the sun, the difference in brightness between opposition and conjunction varies less than
with Mars, from about -2.9 to -1.8 magnitude. Always a bright planet, Jupiter comes to opposition a month later each year, moving approximately from one zodiacal
constellation to the next.
The 4 largest of Jupiters 60+ moons are easily visible through binoculars or a small telescope, ranging from 4.6 to 5.6 in magnitude. The innermost,
Io, takes 1.8 days to orbit the planet making its motion easily detectable within a few minutes.
Type: Gas Giant, Distance from Sun: 1,429 million kilometres (888 million miles)
Orbit Around Sun (Equatorial Rotation): 10,759 days Polar Rotation: 10.66 hours
Temperature: -184 degrees C Atmosphere: Hydrogen, Helium, Methane
Diameter: 120,536 kilometres (74,898 miles) Mass: 95 x Earth
Inclination of Axis: 26.73 degrees Number Of Moons: 62 Rings: Yes
SATURN, at magnitude +0.6 and in Libra, continues to be visble in the south-eastern sky before dawn. The apparent
tilt of the rings, as viewed from Earth, is almost 19° so is beautifully displayed through a telescope.
The diagram shows Saturns rings closing with the south pole presented towards Earth and the far side of the rings no longer appearing clear of the planets body.
In 2009 the Earth passed through the ring plane making the rings invisible for a short while. It was the first time since 1997 that the planets magnitude has faded to
Saturn moves more slowly than Jupiter and can remain in the same constellation for several years. The brightness of the planet depends on the
aspect of its rings, as well as its distance from Earth and the Sun.
The planet crossed the equator into the northern hemisphere in 1996 where it remained until 2010 with the southern side of the ring system
facing the earth. Because of its distance, its brightness varies little between opposition and conjunction but is affected by the huge ring system. Seen edge on the
rings contribute little or no light.
Every 15 years the plane of Saturn's rings passes through the sun, illuminating first the north and then the south side. For a few days the
rings are edge on to the sun. About the same time the Earth passes through the ring plane and, depending on the Earth's position, this may happen just once or 3 times.
During 1995/96 there was a triple crossing and the next will be 2038/39. The last single crossing was in 2009 and the next will be 2025.
Saturn's largest moon, Titan, is visible in small telescopes orbiting outside of the ring system.
Type: Gas Giant, Distance from Sun: 2,871 million kilometres (1,784 million miles),
Orbit Around Sun (Equatorial Rotation): 30,864 days, Polar Rotation: 17.2 hours,
Temperature: -184 degrees C, Atmosphere: Hydrogen, Helium, Methane,
Diameter: 51,117 kilometres (31,763 miles), Mass: 14.6 x Earth,
Inclination of Axis: 97.92 degrees, Number Of Moons: 27, Rings: Yes
Brightness varies slightly, reaching a maximum of +5.6 magnitude at opposition. This is bright
enough to see with the naked eye but identifying it against the stars is difficult. If its location is known, Uranus is easily seen through binoculars. At closest
approach, Uranus is 2,854 million kilometres (1,773 million miles) from Earth.
Type: Gas Giant, Distance from Sun: 4,496 million kilometres (2,794 million miles),
Orbit Around Sun (Equatorial Rotation): 60,190 days, Polar Rotation: 16.17 hours,
Temperature: -223 degrees C, Atmosphere: Hydrogen, Helium, Methane,
Diameter: 49,527 kilometres (30,775 miles), Mass: 17 x Earth,
Inclination of Axis: 28.8 degrees, Number Of Moons: 13, Rings: Yes
Neptune has an average magnitude of 7.9 which varies little with changing distance. At its closest,
Neptune is 4,341 million kilometres (2,697 million miles) from Earth.
Type: Dwarf, Distance from Sun: 5,869 million kilometres (3,647 million miles),
Orbit Around Sun (Equatorial Rotation): 90,465 days, Polar Rotation: 6 days 9 hours,
Temperature: -234 degrees C, Atmosphere: Methane, Nitrogen,
Diameter: 2,390 kilometres (1,485 miles), Mass: 0.02% of Earth,
Inclination of Axis: 122 degrees, Number Of Moons: 3, Rings: No
No longer an offical planet and never brighter than +13 magnitude, Pluto is only visible through powerful telescopes.
Last quarter: 5th
New moon: 11th
First quarter: 18th
Full moon: 27th