Dundee Astro - Sky Notes

January 1st     sunrise     0846 UT   sunset     1545 UT
January 15th   sunrise    0835 UT   sunset     1607 UT
January 31st   sunrise    0810 UT   sunset     1640 UT

In mid-January, the sky is reasonably dark between 1730 and 0700 UT.

The Sun travels through the zodiacal constellation of Sagittarius for the first part of January, moving into neighbouring Capricornus on Tuesday 20th.

The Earth is at perihelion – the closest point to the Sun on its annual orbit – on Saturday January 3rd, when it lies at a distance of 91.4 million miles (147 million kilometres). This is around 3% closer than at its most distant in July.

The Moon is at broad gibbous phase at the start of January; on the evening of Thursday 1st it appears to the upper left of the bright star Aldebaran in Taurus.

Full Moon falls on the morning of Saturday January 3rd. That evening, the Moon rises in the north-east 30 minutes before sunset and shines high in the south shortly after midnight. Throughout the night the Moon lies just above the bright planet Jupiter.

After this, the waning Moon rises later in the evening; on the night of Tuesday 6th into Wednesday 7th it appears to the lower left of the star Regulus in the constellation of Leo.

Last Quarter is on Saturday January 10th; the half-illuminated Moon rises in the south-east shortly after midnight and is low in the south at dawn.

The narrowing crescent Moon may be followed into the dawn twilight up until the morning of Wednesday 14th.

New Moon is on Sunday January 18th, and the young crescent Moon should become visible again low in the south-west from Tuesday 20th onwards. After sunset on Thursday 22nd, the narrow Moon will appear to the lower right of the planet Saturn; on the following evening, Friday 23rd, the Moon will lie just above Saturn.

First Quarter is on the morning of Monday January 26th; the half-illuminated Moon will appear high in the south as the sky grows dark.

On the night of Tuesday 27th, the gibbous Moon will travel just above the Pleiades star cluster; between 9.00pm and 10.30pm, the Moon will pass directly in front of some of the brighter stars in the north-west of the cluster. Binoculars or a small telescope will however be required to see the stars of the Pleiades against the bright moonlight.

On the evening of Friday 30th the wide gibbous Moon will again appear above Jupiter.

Mercury is rising only about 30 minutes before the Sun in early January and will be difficult to spot very low above the south-east horizon at dawn. It sinks a little lower each morning before passing behind the Sun at superior conjunction on Wednesday 21st. It then slowly moves into the evening sky but remains all but lost in the bright twilight, setting just 30 minutes after the Sun by the end of the month.

Venus also passes through superior conjunction this month, on Tuesday 6th, and begins to emerge into the evening twilight too as the month progresses. In the last few days of January it lies close to Mercury just above the south-west horizon; however, this means that it too is setting just half-an-hour after the Sun and despite shining at magnitude -3.9 it may be hard to find in the twilight glow.

Mars is the third planet to be in conjunction with the Sun in January, on Friday 9th, and it won’t be visible at all this month.

Jupiter is at opposition on Saturday 10th, when it lies opposite to the Sun in the sky and is at its brightest at magnitude -2.7. The giant planet rises in the north-east around sunset and shines high in the south at midnight, lying among the stars of Gemini to the lower right of Castor and Pollux. Jupiter is also at its closest to the Earth, at a distance of 393 million miles (633 million kilometres).

Saturn is in the south-west in the early evening during January, setting just before 2300 UT at the start of the month and soon after 2100 UT by the month’s end.

Uranus lies in eastern Taurus about 5deg to the south-west of the Pleiades, and is easily seen in binoculars at magnitude 5.6.

Neptune is at magnitude 7.9 in south-west Pisces, about 2.5 deg north-east of Saturn

January evenings sparkle with a spectacular array of stars – a single glance to the south takes in five of the ten brightest stars in the entire night sky, including Sirius, the brightest of them all.

Centrepiece of this dazzling celestial panorama is the large and distinctive outline of Orion the Hunter, with his central belt of three stars, shoulders above and knees below. The red giant star Betelgeuse marks his left shoulder, and blue-white Rigel his right knee. Following the line of the belt stars upwards to the right leads to the orange star Aldebaran in the V-shaped head of Taurus the Bull; a little further along this line is the star cluster of the Pleiades or Seven Sisters.

Orion’s belt points downwards to Sirius, often known by its nickname, the Dog Star. As well as being the brightest of the night-time stars, Sirius is also one of the closest, lying about 8.5 light years away – around 50 million million miles. Although it is actually a white star, Sirius always twinkles strongly, appearing to flash different colours as it does so.

The Square of Pegasus and the stars of Andromeda are in the south-west, with the ‘W’ of Cassiopeia just above. Below Andromeda are the small but notable constellations of Triangulum and Aries, the Ram. Low in the south-west is the large and rather faint outline of Cetus, the Whale.

Almost overhead are the stars of Perseus and Auriga, while the zodiacal constellation of Gemini with its twin stars Castor and Pollux is high in the south-east, this January joined by the bright planet Jupiter. Below Gemini is the bright star Procyon, often referred to as the ‘little Dog Star’. Low in the east is Leo, with the bright star Regulus at the bottom of the distinctive ‘Sickle’ of stars representing the Lion’s head.

The seven stars of the Plough are in the north-east, the two ‘pointer’ stars showing the way to the Pole Star; low in the north-west are the stars Deneb in the cross-shaped constellation of Cygnus the Swan, and Vega in the small group of Lyra, the Lyre.

The Milky Way appears as a faint band of light, stretching from Deneb in the north-west, overhead through Cassiopeia, Perseus and Auriga, and into the south-east between Orion and Gemini. January evenings are among the best of the year for exploring the winter Milky Way with binoculars and small telescopes.