Astronomical Astronomer's Almanac to All Things Astronomy

The Astronomical Astronomer's Almanac to All Things Astronomy was an astronomy handbook written before the Era of Harmony by an unknown author. The book, or at least the edition owned, was blue with yellow trims. According to the librarian, the book was really old and contained information about "stars, moons, planets, the universe". In the Era of Harmony, Spike ended up destroying Twilight's copy of the book by accidentally sneezing fire into it, though the lied about doing so until Twilight found out.

When the mare found out, she scolded the dragon and told him he wasn't being the spike she knew and loved, causing Spike to believe she didn't love him anymore and so he ran off.