admiring the constellation of Cancer, reflected in a Brook
First of all, an explanation of the title to this organ trio sonata: just translate the phrase above from English into German and you will get the joke!
This sonata was intended as an exercise in composing in Baroque style. It is very simple, obeys all the usual rules that Cancer and Brook had to follow in their day.
So, the first movement is divided into two parts of equal length, each part repeating and the first half ending in the dominant key. The second half begins in the dominant and gradually modulates through the subdominant to the finale in the tonic. The theme is composed of two of the simplest motifs in music: an arpeggio and a scale. In the first half the arpeggio rises and the scale descends, which is reversed in the second half, finally combining both.
As its name suggests, there are only three parts, and the entire piece is written in contrapuntal style. The last movement is based on a theme by Bach.