Bright companion

Ken Kennedy, of Dundee Astronomical Society, tells us what we can expect to see in the April sky.

“Following the tail of Leo the lion eastwards we come to the zodiacal constellation of Virgo which lies between Leo and Libra,” he says. “The brightest star in Virgo is Spica, which is a very close binary star in which both components are blue and orbit round each other in only four days.

“Because of their closeness to each other, both stars are distorted into egg shapes but they are not able to seen individually with a telescope.

“This year, Spica has a brighter companion not far above it. This bright yellow object is not a star however, but the planet Jupiter. Jupiter orbits the sun in just less than 12 years so moves from one of the 12 constellations of the zodiac to the next every year. This is a bit of an approximation, as each of the constellations covers a different area of the sky.

“Over the past few years Jupiter has been becoming lower in our sky and will continue to do so for the next few years so it will be worth having a look at the planet before it sinks to an elevation which makes it much less observable.

“Binoculars held steadily will show the four Galilean satellites of Jupiter, so called because they were first seen by Galileo in 1610. If you have a look on consecutive nights, you will see the positions of these satellites change with none to four of them appearing on each side as they orbit the planet.

“A small telescope will reveal several bands of dark and light cloud drawn out by Jupiter’s rapid rotation. A larger telescope will show more of these cloud bands with some of their irregularities, and the Great Red Spot, a massive storm which has been active for 150 years.

“The first meteor shower since the Quadrantids at the beginning of January makes an appearance from April 18 to 25. This meteor shower is known as the Lyrids as they appear to radiate from the constellation Lyra, quite close to the bright star Vega. Conditions this year are favourable as the moon is a slim 20-day old crescent making for darker conditions. This meteor shower has been known for nearly 2,700 years and may have been more active then as the Chinese recorded that they ‘fell like rain’ in the year 687BC.

“Mercury will be low in the west during early April setting one and a half hours after the sun, after which it will be lost in the twilight. Having been a fine sight in the evening sky for two months, Venus becomes a morning object in April rising in the east at about 5am.

“Mars remains low in the west setting around 10pm and presents a very small disc of four arc seconds. Mars moves from Aries into Taurus on April 12. Jupiter rises at around 7pm in April and is well placed in the south by midnight.

“Saturn rises at 1am and is low in the south by 6am but by then will be fading into the brightening sky. This is a poor year during which to observe Saturn.

“The moon is at first quarter on the 3rd, full on the 11th, at last quarter on the 19th and new on April 26.”