Detail of the organ pipework at St Michael's, Cornhill, London. Photo: Simon Jacobs There's a powerful astrological theme to Martin Baker's organ recital at St Michael's Cornhill on Monday 13 March, as he gives the world premiere of Jonathan Hagger's Great Conjunction Triptych: Seven Vignettes for Organ. Jonathan's piece reimagines a painted triptych in music.  'A very small silver lining to the multiple lockdowns of the pandemic was that they allowed time for composition,' he says. 'Faced with news that was never good it seemed appropriate to look beyond our earthly world for solace.' He noted…