EYES ON THE NIGHT SKY: FEBRUARY 2018
Welcome to February’s edition of Eyes on the Night Sky. This month, there are still plenty of early, dark evenings to view your favourite objects, even though the nights are starting to draw out.
The New Moon occurs on 15th February and around that time, watch out for earthshine before dusk on 19th February, which is where the rest of the Moon’s surface can be seen, illuminated by the Earth’s light. It is also more poetically known as the “ashen glow” or, “the old Moon in the new Moon’s arms” and is very lovely to look at. If you were standing on the Moon looking at the Earth, you would see that the Earth is fully illuminated by the Sun which causes this effect. This can be seen any time in the year around the time of a New Moon at twilight. There is no Full Moon in February, as the previous one was on 31st January, which is commonly known as a Blue Moon month, a second full moon in a calendar month. In fact, there will be a second Blue Moon month in March, where another two Full Moons occur on 2nd and 31st March!
Observing the Moon’s surface with a telescope can be easy and incredibly rewarding. Take time to study the Lunar Terminator, which is the sunrise/sunset line that sweeps across the surface of the Moon, or the area where the light and dark parts of the Moon meet. It’s a fascinating phenomenon to study, as the Sun’s light falls across the features of the Moon, craters and other lunar features stand out in stark relief. The Moon can easily take high magnification and through your telescope, you can see elongated shadows of lunar mountains, which can really take your breath away.
Bodes Nebula comprises two galaxies, M81 and M82, situated in the constellation of Ursa Major. It was discovered in 1774 by Johann Elbert Bode, a German astronomer. These galaxies are 12,000,000 light years away, which makes them some of the more distant Messier objects. They are also starburst galaxies, which mean they have an exceptionally high rate of star formation. Through an 8 inch telescope, M81, a barred spiral galaxy, appears to be an oval-shaped patch of light, whilst M82 appears as cigar-shaped, which is why it is commonly known as the Cigar Galaxy. M82 is around 5 times more luminous than the Milky Way. In dark skies, you may be able to tease out the dark rift intersecting its centre. These galaxies can also be seen through 10 x 50 binoculars and on an exceptionally clear and transparent night, with the eyes!
Staying around Ursa Major, the Whirlpool Galaxy (M51) in the constellation Canes Venatici, comprises two galaxies which are situated some 25 million light years away: NGC 5194 and the smaller NGC 5195. The Whirlpool galaxy is a visual treat as the spiral formation of NGC 5194 can be seen through a 6 inch telescope under dark skies. Through larger telescopes, one of NGC 5194’s spiral arms can be seen connecting to its smaller companion galaxy. It is believed that the loose spiral arm formation is directly influenced by NGC 5195’s gravitational pull and recent research has revealed that the smaller galaxy is passing close behind. With careful observation under dark skies, a small, fuzzy blob can be observed with 10x50 binoculars.
The Owl Nebula (M97) can be seen through a 6 inch telescope but can be challenging target and worth discovering. Also in Ursa Major at 2030 light years distant, it is a planetary nebula, formed by expanding ionised gas from an old, red giant star. Its owl-like face with two, round eyes may be observed with larger telescopes with 8 inch aperture and above. On exceptionally transparent nights in the UK, at least one of the eyes can be seen with smaller telescopes. Whilst you are in the region, see if you can find the nearby galaxy, M108, which will look like a thin sliver of light.
Towards the end of the month, Venus starts to emerge into the evening sky and sets an hour after the sun. At the very end of February, try and look out for Mercury as well, as it sets to the lower right of Venus, some 4 degrees above the horizon.
Mars rises around 3am over the month. On 9th February at around 4am, the Moon will make a close pass with Mars and also with Jupiter, which is currently the second brightest object in the morning sky.
By the end of the month, Jupiter, which is currently the second brightest object in the morning sky, rises at 12:30am and makes a worthy target to study, with the dance of its Moons, the wonderful moments of clarity when you see with high magnification though a telescope, whorls, barges and banding on the gas giant’s stormy surface. Watch out for the Great Red Spot and the black pinpoints of shadows cast by Jupiter’s Moons.
Saturn sits low in the south east during twilight and if your horizon is low enough, great views of its rings can be seen as the planet tilts forward towards us, providing an open display of its rings. Because it is low on the horizon, there may be atmospheric turbulence and the planet may appear to ‘boil’. However, as it is a morning object, you may experience stable views of this planet before the Sun heats the landscape. As the year progresses, this planet rises higher into the night sky.
Lunar terminator, by Steve Ibbotson www.astrosphere.org.uk
Earthshine, by Steve Richards www.nightskyimages.co.uk