Sky Notes for April 2012, with James Abbott
Daylight continues to increase rapidly throughout April and by the end of the month evening twilight does not fully end until nearly 11pm BST.
Jupiter and Venus continue to separate after their close encounter in March. Jupiter becomes increasingly lost in the evening twilight as the month progresses, but Venus remains well placed as a brilliant object in the West as it gets dark. Venus will be fairly close to the young Moon on the evenings of the 24th and 25th. As our sister planet begins to swing in between the Earth and Sun on its faster orbit, so the phase decreases. Venus starts the month with a phase of just under 50%, but ends it at less than 30%, with the diameter steadily increasing as it gets closer to us. At its very closest, Venus can just exceed 1 arc minute in diameter, larger than Jupiter, but much more difficult – and dangerous – to observe near the Sun.
Lower in the sky in the South East at the same time will be another pair of bright objects about 5 degrees apart, Saturn and the star Spica. The low April Full Moon will be close to the pair on the night of 6th/7th April.
Mars is now slowly fading but remains well placed for observation. In mid-month Mars is in the South around 10pm BST, about 5 degrees to the left of Regulus, the brightest star in Leo.
The Lyrid meteor shower peaks in the early hours of the 22nd April and this year there will be no interference from the Moon. The shower is active over about a week but the best time to look will probably be late evening on the 21st and then on after midnight.
At 11pm on the 21st, the shower radiant will be about 30 degrees up in the North East, not far from the brilliant star Vega. Its best to look either side of the radiant rather than straight at it to stand a chance of catching sight of fast moving meteors.
The Lyrids are not usually the most active of showers but have produced outbursts in the past. But even if 2012 is a normal return, a watch of even half an hour near maximum should catch a few. Occasional bright Lyrids can leave luminous “trains” in the sky which can last for several seconds or longer.
James Abbott is an astronomer, NEAS member and CfDS Regional Information Officer.