The Night Sky in January
Venus is currently shining away in the evening twilight in the west. At the opposite end of the night, Mars currently appears dim in the morning sky, but this is set to change. The Red Planet will brighten later in the year, outshining even Jupiter.
On Jan 10, there’s a penumbral eclipse of the Moon, appearing as a subtle dark shading towards the Moon’s southern edge. A penumbral lunar eclipse occurs when the Moon passes through the weak outer portion of the Earth’s shadow in space, the penumbral shadow. A more familiar lunar eclipse occurs when the Moon passes through the dark umbral shadow that lies centrally within the penumbral shadow. The penumbral eclipse takes place from 17:08, lasting until 21:12 with maximum shadow immersion occurring at 19:10. As mentioned above, Mars is currently a morning object. Between Jan 18-20, it’s located near its celestial rival, the star Antares in Scorpius. “Antares” literally means “rival of Mars’” a title bestowed because, to the naked eye at least, it has the same colour as Mars. Antares is a red supergiant star, the 15th brightest in the night sky. It is 550 light years distant and possibly 800 times larger than the Sun. A 21 per cent lit waning crescent Moon joins the planet and star on the morning of Jan 20.
Another famous red supergiant is Betelgeuse in Orion. Over past weeks, observations have shown this star to have faded slightly. As a supernova candidate, the fading caused some excitement. However, Betelgeuse is variable and the observed fade appears to be nothing out of the ordinary.
On Jan 27, Venus appears close to distant Neptune. Although Neptune is too dim to be seen with the naked eye, binoculars will show it. On the evening of Jan 27 using binoculars or a telescope, look for Neptune immediate above Venus. If you do manage to spot them, you’re looking at the brightest and dimmest planets visible from Earth. Venus appears 52,000 times brighter than Neptune.
The following day on Jan 28, try and spot the 12 per cent lit waxing crescent Moon roughly one third of the way up the sky, due south at 15:00. If you do find it, look 10 apparent Moon diameters to the north-west (above right) of the Moon’s crescent. This is where Venus is located. If the sky is clear and your eyesight sharp, it is possible to see Venus in the daytime sky. Later that evening, both objects will still be together and much easier to see over towards the west.
In the night sky, Orion the Hunter leads the way; an obvious pattern thanks to the three equally spaced and similar brightness stars that form his belt. Extend a line from the star in the south-west (lower right) corner of the main pattern of Orion, through Betelgeuse in the north-east (upper left) corner, for one-and-a-half times again to arrive at a pair of similar brightness stars known as Castor and Pollux. Both stars represent the heads of the heavenly twins Gemini. Look closely and you’ll start to see subtle differences between them. Pollux appears slightly brighter and has a definite orange hue compared to Castor. In reality, they aren’t twins at all of course, their association being a line of sight effect. Castor lies 51 light years from the Sun, Pollux 34 light years. Although Castor appears as a single star to the naked eye, its real make-up is more complicated. This is a sextuplet system, six stars arranged as three close pairs.