EYES ON THE NIGHT SKY: MARCH 2019
This month, the Sun crosses over the imaginary equatorial line (Celestial Equator) in the sky above the Earth’s equivalent. This event is called the March Equinox. This year, it occurs on 20th March and so traditionally, is the first day of spring. Don't forget that the clocks go forward by one hour this month - Sunday, 31st March 31 at 1 am.
This month, try to spot the large asterism known as the ‘Spring Triangle’, comprising three bright stars: Regulus in the constellation of Leo, Spica in the constellation of Virgo and Arcturus in the constellation of Boötes. Red giant Arcturus is 113 times brighter than our sun, yet only 1.5 times larger. It is the brightest star in the northern celestial hemisphere and the fourth brightest in the night sky. The Spring Asterism can be seen rising in the south-eastern sky at around 10.30pm at the beginning of the month and 8.30pm at the end.
Another easy target to look for with the unaided eye is a conjunction between Jupiter and the Moon in its last quarter phase on 27th March at around 3am. Separated by one degree which is two moon widths, this will be a pleasing object to look at. Take the opportunity to study four of Jupiter’s moons with binoculars on a steady mount or a small telescope. This conjunction will be visible until 5am. A bonus planet, Saturn rises in the south east at 3.30am.
The New Moon occurs on 6th March and the Full Moon on 21st March.
Jupiter rises at around 3am at the beginning of the month and 1.30am at the end. The planet will not rise very high in the sky this season. However, it will provide a very pleasant sight in the morning sky and always an interesting study with the dance of the Jovian Moons viewed through steady binoculars or a telescope.
Those with small to large telescopes might enjoy the challenge of galaxy hunting. M101, or the Pinwheel Galaxy, lies above the tail of the Ursa Major constellation. You will need dark skies to see this one, as the galaxy’s surface brightness is low and it will be a challenge to see in light polluted skies. However, in dark skies, and due to its high position it can be spotted in binoculars and will resolve as a fuzzy oval with a brighter, central core in small telescopes around 6 inches of aperture.
In apertures of 12 inches and above, if the sky is free from haze, a spiral structure can be seen. M101 was discovered by Pierre Pierre Méchain, who described it as a "nebula without star, very obscure and pretty large, 6' to 7' in diameter, between the left hand of Boötes and the tail of the great Bear….”. He informed Charles Messier of his discovery, who included it in his catalogue.
Even though it may appear to be a fuzzy blob to our eyes, this massive galaxy is 170 light years across, which is nearly twice as large as the Milky Way! It is amazing to consider that we can see it when it lies at a distance of 21 million light years from us.
Pronounced Bow – oaties, this constellation rises in the north-eastern sky at around 7pm. Boötes is the Greek word for herdsman, or ploughman and was first catalogued by Ptolemy in the 2nd Century. It is the 13th largest constellation in the sky and contains five stars with known planets. This constellation has many myths surrounding it – one of the more sensible ones which doesn’t involve tragedy or betrayal is that this was a tribute bestowed by the goddess Ceres, upon the inventor of the plough.