I decided to take a full picture that goes with the detail here http://www.pbase.com/helenpb/image/132508439 and now I know why I didn't attempt it on my first visit to the museum. But light fixtures and museum barrier notwithstanding, it's a pretty impressive altar piece. The church is said to be in Burgenland, Austria (according to the museum catalog), but I'm unable verify that, especially the name of the church.