There is a very brief shot of the sun eclipsed by a crescent moon. That would be impossible in our world, but (according to the books from which the show is derived) the moon of Fillory really is a crescent; it doesn't just look that way part of the time.
This is the only episode where Laci J Mailey plays the character of Fen. From Season 2 onward, she's played by Brittany Curran, having been recast.