Posted by Callum Potter at 14:40 on 2011 Nov 17
I don’t know if this is what you are looking for Martin, but the Sky and Telescope magazine website has a useful calculator, and a table through to March 2012.http://www.skyandtelescope.com/observing/objects/javascript/3304091.htmlI have not checked how accurate the GRS transit times are, though.Regards, Callum