Shropshire Sky At Night – April
With spring well under way and the change to British Summer Time, we need to revise our observing habits as astronomical twilight comes later and later in the evening.
Astronomical twilight occurs when the Sun is between 12 degrees and 18 degrees below the horizon. Most stars and other celestial objects can be seen during this phase. However, keen stargazers and astronomers may have to delay their observation of the fainter stars and galaxies until the Sun is greater than 18 degrees below the horizon.
On the 12th the Moon will be located on the same side of the Earth as the Sun and will not be visible in the night sky. Referred to as a new moon, this is the best time of the month to observe faint objects such as galaxies and star clusters because there is no moonlight to interfere.
At 9.15pm on the 27th, given clear skies, there should be an excellent opportunity to watch the first of three Supermoons of the year. Although the Moon will be near its closest approach to the Earth and may look slightly larger and brighter than usual, no one can explain why it appears so large when it is close to the horizon. It seems like an optical illusion is the best explanation we can offer.
Towards the end of the month both Venus and Mercury are evening objects, providing that you have a flat west-north-western horizon. The pair of horizon-huggers do not climb higher than six degrees, but with the brightness of Venus at mag -3.9 and Mercury at mag -1.6 they should be an easy target with a pair of binoculars.
Remember do not sweep near the horizon with your binoculars or telescope until the sun has set.
Alternatively for the early risers, Jupiter and Saturn can be spotted among the stars of the constellation Capricornus, low at sunrise, although you will need an unobstructed view of the southeast horizon. Detailed views may be difficult but Jupiter’s moons and the rings of Saturn should be observable through a small telescope or suitable binoculars.
Shooting stars (meteors) appearing one after another across the sky is always an exciting event. The April Lyrids are active between the 14th and 30th. The Lyrids is an average shower, usually producing about 20 meteors per hour at its peak.
It is produced by dust particles left behind by comet C/1861 G1 Thatcher, which was discovered in 1861. It peaks this year on the night of the 22nd and morning of the 23rd and can produce bright dust trails that last for several seconds. However the bright moon will be a problem this year, with its glare blocking out all but the brightest meteors.
Be patient and you may still be able to catch a few good ones. Best viewing will be from a dark location after midnight, with the meteors radiating from the constellation Lyra, hence the name Lyrids, but they can appear anywhere in the sky.
Steve Szwajkun is a Fellow of the Royal Astronomical Society
