Austria: St Stephen, Stockerau

I recently received this envelop from a friend. The item of interest is the postmark. It features the 19th century organ at St Stephen's Church, Stockerau Austria. It seems the organ was built in 1888 by Johann Kaufmann of Vienna. I have not been able to find a modern image of the instrument. But I believe this is the stoplist. The image below is from the church's website. In the background one can see the organ. I believe there is enough of the instrument showing to declare it a match to the envelop image.

As I mentioned, it is not the stamp on this cover that is of interest, but rather the postmark. It is used to cancel the stamp as one would expect. But it also appears again on the left side of the cover. It seems the postmark was created to celebrate the 275th year of the church's tower. It was produced December 1, 2000 for the Christmas season. In the US an entity may petition the USPS for permission to produce a special postmark for an event of limited scope. Usually the postmark is used for a limited time, and within a limited area (a single ZIP code). I'm not sure how things work in Austria, but because of conventions of the Universal Postal Union, I suspect similarly.

The 6 shilling stamp (Scott 1606) is a detail of a stained glass window located at the Mariastern-Gwiggen Monastery. The script above the male figure seems to read "Sanctus Benedictus." The figure is holding a bishop's crozier and a communion chalice. A building in the lower right corner may be the monastery itself. There is a second stamp of some sort on the left side of the cover. It seems to be a 50 groschen surcharge, perhaps to pay for the special postmark? The cover was sent to Spain. Eventually wound up in the hands of my colleague Mark Jameson in Britain, and now to mine. All in all a nice piece of organ information.

Elsewhere on the church website, I found this image of the console. Without looking at every image on their gallery, I still haven't found the complete instrument; plenty of pictures of the east end however!