Dublin astronomer finds third supernova with self-made telescope

An amateur astronomer with an eye for exploding stars in the night sky has celebrated the latest celestial discovery from his back garden with a cup of tea.

Dave Grennan, 42, hit the jackpot in the heavens over his suburban Dublin home on Good Friday using a telescope he built himself which picked up a 170 million-year-old dying sun 100 times the size of ours.

“It was 11 o’clock at night when I actually got the first look at this and by 1am I was fairly certain and at that time of night there was nothing else for it but a strong cup of tea,” he said.

“What excites me about this one this time is the telescope – I built it myself, right down to the polishing of the lenses.”

Mr Grennan, a 9-to-5 software developer, has discovered three supernovae or exploding stars over four years from a shed at the bottom of his garden.

The success rate is all the more significant as Ireland only averages six to 12 clear skies a month and the nights from May to August are too bright to hunt for the celestial phenomenon.

The latest discovery was confirmed over the weekend by the International Astronomical Union which gave it the unique name Supernova 2014as.

It was made in a galaxy which at this time of year appears beside the constellation known to most people as the Plough, or Big Dipper.

“You won’t see any trace of this looking at the night sky with the naked eye, it’s about 100,000 times fainter than what you can see,” Mr Grennan said.

The stargazer has written a specific computer programme with complex algorithms and criteria to allow his telescopes to target certain galaxies at certain times even if he is not in the shed. He then reviews hundreds of images with the naked eye.

“I don’t think I could do this if I had kids, but now when I think about it maybe it would be beneficial enough if I was up half the night and bottle feeding,” Mr Grennan said.

“But one of the misconceptions is that I’m out there in the freezing cold and dark with a big coat on me looking through a telescope at the night sky - sometimes, or most of the time, when I’m looking for these things I’m inside watching the television.”

When Mr Grennan made his second supernova discovery in 2012 he was contacted by Lomonosov Moscow State University which admitted its scientists had failed to pick up on the discovery weeks earlier.

Planets and asteroids can be named but the fleeting supernovae are registered according to the year of discovery. They are the spectacular explosion of a star or sun like ours, caused by a violent collapse or the weight of material being pulled into its orbit.

Mr Grennan made the first discovery of a supernova from Irish soil in 2010 and two years before that he discovered an asteroid – a minor planet three metres wide – and named it after his late mother, Catherine Griffin, who encouraged his interest in the stars when he was a boy.

David Moore, head of Astronomy Ireland, said: “He’s certainly Ireland’s most prolific supernova hunter.”

Despite his success in his spare time Mr Grennan has quite a way to go to top the success rate of Tom Boles, a retired telescope maker originally from Glasgow who has more than 100 discoveries to his name and an asteroid named in his honour.