February is usually a cold, dreary month, but as we move towards the middle week, we can feel the warmth of spring and summer just around the corner. And Valentine’s Day on 14 February gives us the chance to share this warmth and love with our partners and companions in life.
In the sky, there are a couple of romance-themed objects on view this month, the best known of which is the Heart Nebula in Cassiopeia, officially known as IC 1805. This delicate emission nebula glows red by the light of hydrogen, ionised by the light of small cluster of stars at the centre of the nebula. Its blue and orange colours come from emissions from ionised sulphur and oxygen, respectively.
This lovely object was discovered by the great deep sky astronomer William Herschel on 3 November 1787 and is almost four times the size of the full Moon. You can find the Heart Nebula high in the north-western sky during February, between Cassiopeia and Cepheus, not far from the famous Double Cluster. However, don’t get your hopes of spying a glowing heart in the sky too high – it’s a very faint object. However, it’s a popular target for astrophotographers equipped for long-exposure photography.
Real lovebirds will have to wait until past midnight in February to locate another heart-shaped object low in the south-west, the Antennae Galaxies. When seen at correct right angle, these two galaxies are lovingly wrapped around each other in an enormous heart-shaped collision of stars, dust and gas. Located low in the constellation of Corvus the Crow, these galaxies are listed as NGC 4038 and NGC 4039 and also in Sir Patrick Moore’s Caldwell catalogue as objects 60 and 61. The main body of the collision is indeed heart-shaped but the galaxies are more popularly known as the Antennae Galaxies because of the two trails of stars emerging from them which look like insects’ antennae.
These galaxies were also discovered by William Herschel in 1785 and are located around 50 million light years from us. At around 11th magnitude, these are not bright objects, and the faint heart-shaped streams are really only seen on photos. To see them on Valentine’s Night you will need at least a 150 mm telescope and a clear sky to the south-west after midnight – and a very understanding partner.