Sky Diary

By April the winter constellations are sinking into the west and the prominent constellation towards the south will be Leo. Leo is one of these constellations which looks like what it represents, a crouching Lion. This goes back to Greek mythology when Leo was seen as the Nemean lion, killed by Heracles as the first of his twelve labours set by King Eurystheus. Leo consists of nine bright stars with six forming the grouping known as The Sickle, shaped like a backwards question mark. The lowest star of the sickle is Regulus, the brightest of the stars of Leo. Regulus is 79 light years from our solar system and, unlike our solitary Sun it is a multiple star with four stars in two gravitationally bound pairs. The brightest of the four stars is classified as a blue-white subgiant and its companion is believed to be a white dwarf star. These two stars orbit each other in 40 days while they orbit the other pair of stars in several millions of years.

Leo is home to a number of galaxies, some of which are relatively bright as distant galaxies go. It is possible to see a few of the brighter ones with a fairly small telescope, one favourite group being the Leo Triplet consisting of Messier 65 and 66 and NGC 3628 which are at a distance of around 35 million light years.

Towards the south-east the bright star Arcturus dominates the constellation Boötes which appears as a kite or cone shape of rather less bright stars. Following just to the east of Boötes is the small semi-circular constellation of Corona Borealis, the Northern Crown. These stars are not particularly bright and April is a good time to see Corona before the brightening nights of summer months. I suggest you might keep an eye on this constellation as one of the stars, T Coronae Borealis, is known to flare in brightness approximately every 80 years. It last brightened in 1946 and early dimming in 2023 led to predictions of another flare in 2024. This did not happen, and it still has not shown signs of brightening, but it is possible that it will suddenly occur at any time. When it does it will be brighter than any of the other stars of Corona Borealis and will appear towards the eastern side and just outside the semi-circle. It should be easily identifiable to the unaided eye, so keep watching when skies permit.

The second notable meteor shower of the year, the April Lyrids, reaches its peak of activity on the 22nd April at around 10pm. In a clear moonless night there could be around 15 meteors per hour seen, but this year there is a 5 day old Moon in Gemini which will not set until 3.30am. This will reduce the number of meteors seen in the earlier part of the evening with the chance of seeing more after midnight until the Moon sets. Occasionally this meteor shower produces considerably more meteors as in 1922 and 1982, so it is worth watching in case 2026 gives a particularly good display.

_{Sky Notes courtesy of Ken Kennedy of Dundee Astronomical Association}