Editing Almagest (section)

==== Constellations in the star catalogue ====
The star catalogue contains 48 constellations, which have different surface areas and numbers of stars. In Book VIII, Chapter 3, Ptolemy writes that the constellations should be outlined on a globe, but it is unclear exactly how he means this: should surrounding polygons be drawn or should the figures be sketched or even line figures be drawn? This is not stated.

Although no line figures have survived from antiquity, the figures can be reconstructed on the basis of the descriptions in the star catalogue: The exact celestial coordinates of the figures' heads, feet, arms, wings and other body parts are recorded.{{sfn|Hoffmann|2017|p={{Pages needed|date=April 2023}}}} It is therefore possible to draw the stick figures in the modern sense so that they fit the description in the Almagest.{{refn|1= These modern stick figures as a reconstruction of the historical constellations of the Almagest are available in the free planetarium software [[Stellarium (software)|Stellarium]] since 2019.{{citation needed|date=April 2023}}|group=note}}

These constellations form the basis for the modern [[constellation]]s that were formally adopted by the International Astronomical Union in 1922, with official boundaries that were agreed in 1928.

Of the stars in the catalogue, 108 (just over 10%) were classified by Ptolemy as 'unformed', by which he meant lying outside the recognized constellation figures. These were later absorbed into their surrounding constellations or in some cases used to form new constellations.{{sfn|Ridpath|2023|loc=[http://www.ianridpath.com/startales/ptolemy-spare.html "How Ptolemy’s spare stars became new constellations"]}}