Unpredictable beasts

Ken Kennedy, of Dundee Astronomical Society, tells us what we can expect to see in the May sky. “It is said that if you have been waiting some time for a bus, two will turn up together,” he says.

“This spring it seems to be the same for comets. Unpredictable beasts, the last really bright comet seen was Halebopp in 1997. In the last few days of 2019, a comet was discovered by Mauna Loa Observatory, Hawaii. It is known as Comet Atlas and is coming towards the sun from the outer reaches of the solar system. Early calculations showed that it was in a similar orbit to the Great Comet of 1844 and that its orbit would take about 5,000 years to complete.

“Comets are fragile lumps of ice and dust and it may be that Comet Atlas is a broken fragment of the Great Comet. From the orbit deduced it was found that Comet Atlas would be closest to earth on May 23 and it was hoped that it would be visible, using binoculars, during May, and best during the last two weeks of the month.

“However, images taken on April 11 showed that it had broken into three parts. It is unlikely now that when it is closest to earth on May 23 it will reach a reasonable brightness. In case fragments survive, it will be worth looking northwards around midnight as it moves into Perseus around mid-may.

“In March, the SWAN camera on board the SOHO spacecraft picked up a comet in the southern constellation of Sculptor. Now known as Comet SWAN, it will be seen from the southern hemisphere until May when it will rise from the constellation Cetus into Pisces, then Aries on May 14 and will pass close to the galaxy Messier 33 on the 16th.