Twilight Sparkle's telescope
Twilight Sparkle owned numerous telescopes in her lifetime. This telescope was her first known one.
In other media
IDW comics
The telescope apparently grew old, dirty, ugly and worn by the Era of Twilight and so Spike and Princess Celestia ventured to Crystal Empire to find the perfect lens' to make her a new one. This telescope was created by Starry Eyed, a famous and skilled telescope creator.