Zachow's preludes to "Wie schön leuchtet der Morgenstern" is written in four parts. Most of the phrases have fore imitations in the other voices before appearing in the soprano voice. Zachow keeps the piece from becoming to academic by interspersing it with a more homophonic episode in the middle in the piece. Another nice detail is the chromatic motiv that appears in the for imitation of the second and fifth phrase of the chorale melody.
The recording was done with the Hauptwerk software and the sample set of the Silbermann organ of the Stadtkirche Zöblitz by Prospectum (http://www.prospectum.com/index.php?language=english&id1=2&id2=8).
Score available here: http://partitura.org/index.php/friedrich-wilhelm-zachow-wie-schon-leuchtet-der-morgenstern