Asteromancers, or Star Mages, believe that the small lights that illumine the night sky are each a tiny fragment of the magic that permeates the universe. The stars are magic, but a single star does not hold enough magic to be at all useful. To think you could "wish upon" a single star is folly reserved only for children. Rather, the power of magic is summoned and controlled by drawing and understanding the relationships between multiple stars. The commonly known constellations and the predictions of Astrology represent only the barest fraction of the truth of this power.
Method of Casting:
An Asteromancer's methods for crafting his spells is as ostentatious as it is precise and is often what leaps to the minds of most laymen when they think of "spellcasting". To cast a spell, the Asteromancer must point to the location of each star in the sky, using a finger, wand, or other pointer device, and call out the stars by name in the precise order that defines the relationship of the spell in question. As the stars do not have to be visible for the spell to work, and the names of stars (such as "Alpha Crucis" and "Kaus Australis") are so much gibberish to the uninitiated, this casting is typically interpreted as simply waving one's hands about and chanting arcane words. While not strictly necessary for casting a spell, most Asteromancers also carry a sextant and astrolabe for calculating the relative positions of the celestial objects involved in the spell.
An Asteromancer's spellbook takes the form of a collection of star charts, plotting the quadrants of the night sky through various seasons and showing the positions of the innumerable stars and their names.
The Limit: (i.e. Why does this guy use Vancian spell-slots?)
Each spell an Asteromancer casts represents a precise relationship between a specific group of stars. While such relationships are easy to trace when the stars in question are visible in the sky, it becomes much more difficult when they are not. Stars cannot be seen during the day, nor when the sky is overcast, and some more complex relationships may be between stars that are on opposite sides of the planet relative to its current rotation. In order to cast a spell, the Asteromancer must know the stars' exact positions at any given time. While more experienced Asteromancers may develop tricks and references to simplify locating the necessary stars, casting spells during the day still boils down to a monumental task of wrote memorization, accompanied by careful tracking of the time and the planet's rotation.
Breaking the Limit:
An Asteromancer who has exhausted his daily allotment of spell slots can attempt to cast additional spells only if he can directly see the stars in question. Without such visual references, a tired mind cannot possibly locate the correct stars. The Astronomancer may freely cast spells using his The Stars are Right ability, even once he has used up his available slots.
The Stars are Right: