This story is a sequel to Celestia Sleeps In

After the accidental discovery of humans, Celestia tasked Lyra with learning about Dale's culture and Dale's language. Two meetings later, a misunderstanding caused Dale and a Coast Guard woman to be inadvertently transported to Equestria. With the two humans hospitalized and communication limited at best, the Equestrians just want to heal them, while back on earth the Coast Guard wants nothing more than to determine what happened to one of their sailors.

After an argument with Luna, Celestia realizes that she is the only creature in Equestria who cannot sleep in. She enlists Twilight to help, and the two of them come up with a spell that will allow her to spend the night on a different world. Unfortunately, all their research failed to reveal that the world they sought was populated. Now, the Princess must decide whether to continue with contact, or destroy the only non-Equestrian witness to their existence.

Cover art is called "Sleeping Celestia" by Briskby

Moving across Equestria was not what Derpy had in mind for her senior year of school. She left all her friends behind just before Hearth's Warming, and found herself in a new school. Now she has to make new friends, as well as prepare herself for life outside school, a task complicated by a decision she makes during Winter Wrap-Up.

A Pony Planet story