The Photographer’s Ephemeris app
But, in addition to that, scouting as well. I went a day or two before to the balcony (a pub actually) to see where would I need to stand in order to avoid a bunch of antennas and other stuff on the roof across the street, so as not to interfere with the church. Turns out, only one extreme corner of the balcony would do, so I came half an hour early to secure a table in that very corner. Turns out, someone was already sitting there, but luckily got up and left just before the moon started to appear.
Coincidentally, there was another couple sitting behind me, also photographers, who, at the time unbeknownst to me, were taking pictures of me taking pictures
The Moon Catcher