Selûne (moon)

Selûne, known as Leira to its inhabitants, was the name of Toril and Abeir's only natural moon. Seen from Toril, it appeared to fit within the size of a human fist held at arm's length. It was quite bright on a clear night, able to cast pale shadows.

Geography
Selûne was about across and was located  away from Toril, although some sages from the late 14 century DR claimed the distance to be some  instead.

Since the revolution and rotation periods of Selûne's orbit around Toril were the same, only one side of the moon always faced Toril, while the far side (referred to by some as the "dark side") could never be seen from the planet.

The visible side of the moon was disguised by a powerful illusion that made it appear to be an airless, barren, desolate place filled with craters and valleys. The illusion drifted about 500 miles (800 km) above the surface. It could only be revealed by a wish spell and, even so, only to the caster. The far side, however, was not obscured by any magic, so its true splendor could be seen from space. All docking ports for spelljamming ships were located on the far side.

Selûne was followed in the sky by the Tears of Selûne, a constellation of very small celestial bodies that was often identified as composed of nine stars, but which in reality consisted of hundreds of asteroids.

Lunar Phases
Selûne was full at midnight on Hammer 1, 1372 DR, and subsequently every 30 days, 10 hours, and 30 minutes. Selûne was also full at midnight on the first day of every leap year. Selûne made exactly 48 synodic revolutions every four years, so the phase of Selûne was the same at the same time on the same date every four years. Selûne was generally full around the first day of each month, give or take a day; festival days served to keep the moon's phases consistent across calendar months and years.

For those who practiced lunar magic, the phase of the moon affected the potency of their spells, peaking in the full moon and dipping at the new moon.

Eclipses
Due to the size and relative rotation of Selûne and Toril, eclipses were quite frequent and commonplace.

Geographical Features
The surface of Selûne had enormous lakes and two large seas. It was dotted with cities connected with one another by beautifully decorated roads. Three large mountain ranges ran the surface of the moon from North to South. The mountaintops of the 12 tallest mountains were constantly molten and gathered heat from the sun during the moon's 15-day-long day. As they cooled down, they shone an incandescent light that was bright enough to read by during most of the moon's 15-day-long night.

Selûne had a remarkably stable temperature, thanks to its magical blanket. Except for the hot mountain tops, the surface of the entire moon was relatively cool, although temperatures never dropped below freezing.

History
By the hand of Selûne, goddess of the moon and its namesake, the moon could be a conduit of her powers. In 1357 DR, her avatar Luna used a bright beam of moonlight to transport Conner and the kittenlord to her inn, Selûne's Smile, and later to crack open the roof of a cavern and blind ogres holding the paladin Priam Agrivar.

Rumors & Legends
In Kara-Tur, it was believed that the Moon Women of the Celestial Bureaucracy were responsible for steering the motion of the Moon along its course.

Notable Locations
The largest and most beautiful building on Selûne was the Leira Trading Center, located in the center of the moon's far side. It consisted of about 50 spelljamming space docks and was surrounded by numerous colorful businesses, theaters, and dwellings. Visitors from Toril arriving at this large complex were usually confined to it and were not allowed to explore the remainder of the moon.

Inhabitants
Selûne's aloof inhabitants, also known as Selûnians, but who referred to themselves as Leirans, had a refined sense of aesthetics that appeared frivolous and foolish to outsiders. The predominant religion among the moon's inhabitants was the worship of Leira. In fact, it was not uncommon for the inhabitants to call their world Leira instead of Selûne. The obscuring illusion that hid the near side of the moon from Toril was a gift from Leira to reward their worship.

Selûnians were extremely suspicious of Torilians, to the point of paranoia. Visitors and merchants from Toril were usually considered spies and were often denied access to restricted areas of the moon, sometimes being even confined to the spaceport where they docked. Selûnians were convinced that Torilians were dangerous and could not be persuaded otherwise.