Bootes. Johannes Bayer (1572–1625). from Uranometria. Hand-colored engraving heightened in gold. Augsberg: C. Mang, 1604. 12 x 15 12 inches sheet, 24 x 27 inches framed. Though he was a lawyer and not an astronomer by profession, Johann Bayer created one of the most memorable seventeenth-century guides to the constellations, entitled Uranometria in honor of Urania, the muse of astronomy. First published in Augsburg in 1603, the Uranometria included celestial maps that were not only highly appealing on a visual level, but also significant in the history of astronomy. They were the first charts to identify astral magnitude (brightness) with a lettering system, using Greek characters for the brighter stars and Roman letters for the fainter.