The Astrologer repeats pictorial devices deployed in the rest of the series such as a large diagonal line that divides the canvas, an interplay of horizontals and verticals that structures the pictorial space, the concentration of the action towards the lower part of the composition and the broad sweep of the curtains on the opposite side. This spectacular approach to composition, making full use of bold diagonals, increases the dynamism of the scene and creates a sensation of depth. Its ultimate aim, however, is to intensify the relationship between the viewer and the painting.
Here Sert introduces two geometrical shapes that attract the viewer’s gaze: the astrologer’s pointed cap and the large sphere held up by the black figure. Sert had used the latter motif, a man with a large sphere, in earlier decorative schemes and it would frequently reappear over the following years to reemerge with powerful significance in the paintings that he executed for the League of Nations some years later. In that scheme the figure was transformed into a great titan straining to hold up a terrestrial sphere.