Markab

Markab is Alpha Pegasi, a blue-white star at about 133 light years, and it marks the southwestern corner of the Great Square of Pegasus, the large and useful rectangle of stars that dominates the autumn sky. Its name, from the Arabic markab, means a saddle, a mount or a vehicle, the place on the winged horse where a rider would sit, an apt name for a star set on the body of Pegasus. With Scheat, Algenib and the shared star Alpheratz it forms the four corners of the Square, one of the most recognisable patterns in the northern heavens.

The Great Square's four corners, Markab, Scheat, Algenib and the shared Alpheratz, are not all equally bright, and Alpheratz's eventual reassignment wholly to Andromeda left the Square's fourth corner permanently borrowed from a neighbouring constellation, a quirk that makes the Square, for all its usefulness as a signpost, technically not a figure contained within Pegasus alone under the modern boundaries. No delineation earlier than the compiling tradition survives for Markab specifically beyond the general character Ptolemy gives Pegasus as a whole, the ordinary situation for a corner star of an otherwise well-known asterism. Markab's position at a corner of so widely recognised a pattern has made it one of the more useful practical signposts for amateur observers new to the autumn sky.

The tradition gives Markab the nature of Mars with Mercury, and Robson reads it for a keen, steady and enterprising mind together with the danger of cuts, blows, fire and shipwreck, the martial half supplying the hazard and the Mercurial half the sharpness. The specific catalogue of violent dangers is the usual late elaboration, to be treated as schematic rather than predictive. The dependable content is the star's position: a bright marker at one corner of the Great Square of Pegasus, part of a pattern that has served skywatchers as a signpost to the autumn constellations for as long as the sky has been mapped.

The specific hazards Robson lists for Markab, cuts, blows, fire and shipwreck, follow the same schematic Mars-supplies-the-danger, Mercury-supplies-the-instrument logic visible across the whole martial-mercurial group of stars in this catalogue, Bellatrix and Alshain among them, a formula the compiler seems to have applied fairly mechanically wherever the pairing recurred. No delineation earlier than the modern compiling tradition survives for Markab specifically, and its violent catalogue of dangers should be read, like similar lists elsewhere in this set of tables, as schematic nineteenth-century elaboration rather than ancient testimony.