Esther Sextan's Star Almanac is a book concerning astronomy, written by Esther Sextan. It contains animated charts and graphs that show the movements of the stars and planets, and can provide information concerning the positions of heavenly bodies at any given moment with as much accuracy as a Muggle computer. The book recognizes only very specific commands, however, requiring a certain amount of expertise to extract any useful information.
A copy of the book is kept by the Charmbridge Academy library. In September of 2008, Alexandra Quick requested books on astronomy while she was laid up in the infirmary; the Star Almanac was among the volumes that Bran and Poe delivered.