Engraving depicting the two celestial hemispheres with their stars and constellations, as well as the paths of comets across the spheres. From the book "Theatrum Cometicum", a treatise on comets. Around the hemispheres are printed notes about the comets, including the places from which they were observed on a given day. Andromeda and the whale Cetus have been pointed out with pencilled-in arrows.
