The sun is a heavenly body, the day star around which the planets revolve. It began to be used as an heraldic charge early, in the arms of de la Hay, c.1255 [ANA2 550]. The sun is most commonly drawn as a disk with multiple rays emanating from the edge; these rays are normally drawn as alternating straight and wavy rays. However, many period depictions (especially in early period) made all the rays straight, and showed no disk; other depictions (especially on the Continent) showed only wavy rays. A sun is thus negligibly different from a mullet or estoile of many points.
A sun “in his splendor” or “in his glory” is depicted with a human face; this artistic nuance seems to have begun in the early 15th Century and had come into common use by Tudor times. A “sun eclipsed” in mundane blazonry is simply a sun sable; in Society blazonry, a “sun eclipsed” is one whose center disk is another tincture than the rays, or whose center disk is obscured by a roundel. In early Society usage, the eclipsed disk was sable by definition; current practice is to explicitly blazon the tincture of the eclipsing. The eclipsing may be of any tincture, but eclipsing of a divided tincture is deemed a step from period practice.
A “ray of the sun” is a demi-sun issuant from the edge of the shield, with one ray elongated to cross the field. The arms of Aldam, 1632 [Guillim2 120] explicitly state the ray’s direction, and this must be done in Society armory as well; the illustration shows a ray of the sun issuant from dexter chief (and therefore bendwise).
The King of Atenveldt bears: Azure, a sun in his splendour Or within a laurel wreath argent, in chief a crown of three greater and two lesser points Or.
The Prince of Insula Draconis bears: Per fess sable and azure, a demi-sun in splendour issuant from the line of division within a laurel wreath, in chief a crescent Or.
Wendryn Townsend bears: Azure, a sun in glory Or.
Esteban San Buenaventura bears: Or, three suns in splendor sable.
Kourost Bernard of the East Woods bears: Sable, a sun eclipsed Or [i.e., a sun Or eclipsed sable].
Gairovald Eburhard bears: Sable, issuant from dexter chief a demi-sun argent.
Pascal Brendan Merredy bears: Vert, a ray of the sun bendwise Or, in sinister chief a chalice argent.