David Grennan explains  Photo: Patrick O'Leary

David Grennan is one of Ireland's top amateur astronomers. By day he works as a systems analyst for CIE.  He has been interested in astronomy as far back as he can remember.  He has used telescopes ranging in size from humble binoculars to the society's 21-inch Millennium Telescope of which he is now the custodian. He has a passion for astrophotography for which we uses a Celestron C9.25-SGT with XLT coatings and a Canon 300D digital SLR camera. David served as Vice Chairman of the society for several years and now writes the Sky Diary pages in Astronomy Ireland's magazine. Contact him at skydiary@astronomy.ie.