Where can I find details about the constellations and night sky characteristics of Toril? Is this information presented in any of the released books?
There's nothing published that I'm aware of. I have a reasonably good knowledge of the Forgotten Realms material presented in Living Forgotten Realms modules, and I don't know of any night sky material there, either.
Candlekeep has an unofficial article about the subject, which is based on official material. There is also a comprehensive discussion thread here, with links to a few visual resources and much discussion of Selune.
In the Forgotten Realms style guide (part of the freely available DMs Guild Creator Resource - Style Guide Resources), on pages 21 through 25, there is a lot of information on the night sky, including information on the Moon (Selûne), eclipses, the Tears of Selûne (asteroids orbiting Toril), important stars, and constellations.