progression writing, "Argo by the Great Dog's [Canis Major's] tail is drawn; for hers is not a usual course, but backward turned she comes ...". The constituent modern constellations In modern times, Argo Navis was considered unwieldy due to its enormous size (28% larger than Hydra, the largest modern constellation). In his 1763 star catalogue, Nicolas Louis de Lacaille explained that there were more than a hundred and sixty stars clearly visible to the naked eye in Navis, and so he used the set of lowercase and uppercase Latin letters three times on portions of the constellation referred to as "Argûs in carina" (Carina, the keel), "Argûs in puppi" (Puppis, the poop deck or stern), and "Argûs in velis" (Vela, the sails). Lacaille replaced Bayer's designations with new ones that followed stellar magnitudes more closely, but used only a single Greek-letter sequence and described the constellation for those stars as "Argûs". Similarly, faint unlettered stars were listed only as in "Argûs". The final breakup and abolition of Argo Navis was proposed by Sir John Herschel in 1841 and again in 1844. Despite this, the constellation remained in use in parallel with its constituent parts into the 20th century. In 1922, along with the other constellations, it received a three-letter abbreviation: Arg. The breakup and relegation to a former constellation occurred in 1930 when the IAU defined the 88 modern constellations, formally instituting Carina, Puppis, and Vela, and declaring Argo obsolete. Lacaille's designations were kept in the offspring, so Carina has α, β, and ε; Vela has γ and δ; Puppis has ζ; and so on. As a result of this breakup, Argo Navis is the only one of Ptolemy's 48 constellations that is no longer officially recognized as a single constellation. In addition, the constellation Pyxis (the mariner's compass) occupies an area near what in antiquity was considered part of Argo's mast. Some recent authors state that the compass was part of the ship, but magnetic compasses were unknown in ancient Greek times. Lacaille considered it a separate constellation representing a modern scientific instrument (like Microscopium and Telescopium), that he created for maps of the stars of the southern hemisphere. Pyxis was listed among his 14 new constellations. In 1844, John Herschel suggested formalizing the mast as a new constellation, Malus, to replace Lacaille's Pyxis, but the idea did not catch on. Similarly, an effort by Edmond Halley to detach