Wie schön leuchtet der Morgenstern

Kauffmann wrote two preludes to the choral “Wie schön leuchtet uns der Morgenstern”. For the organ solo one, Kauffmann prescribes the use of a Bourdon 16′. That seems a bit strange to me, for a choral whose text features words like Morgenstern and Freudenschein. In the recording I follow Kauffmann’s registration prescription, but play the music an octave higher than notated.

Registration:
BW: Vox Humana 8′, Flagfluit 4′
HW: Bourdon 16′
HW+BW

Score available here: http://partitura.org/index.php/georg-friedrich-kauffmann-wie-schon-leuchtet-der-morgenstern/