Semler is another one of those celestial cartographers who is unknown except through his atlas. The Semler atlas is immediately distinguishable from all its predecessors by the black background on the plates. Each plate was printed from a woodblock, cut
only to outline the constellations and pinpoint the stars. Each of the 35 woodcuts has a different oriention, which can sometimes be disconcerting, although celestial north is indicated by an arrow on each plate. Some of the illustrations are quite attractive, such as the one that depicts Centaurus, standing over the Southern Cross, engaging Lupus the Wolf. Semler derived all of his constellations and star positions from the atlas of Hevelius, as we see in comparing his Auriga to that of Hevelius. Semler even included all nine of the new constellation figures that Hevelius introduced. The plate of Auriga reveals his indebtedness. But it also reveals that Semler rejected the outside-in viewpoint of, so all the figures are reversed. They are not, however, turned back to front, which can not be so easily accomplished as reversing a woodcut.