T'Rukhemai, named to mean "eye of the watcher" in the Vulcan language was a moon of a sister world of Vulcan, T'Rukh. The moon moved in a low, fast-moving orbit, and it was often visible from Vulcan as a dark reddish sphere, looking like a pupil in a giant eye when it passed through the center of planet when viewed from Vulcan. T'Rukhemai was slightly larger than Earth's moon and moved through its orbit so quickly that its movement was almost visible to the naked eye. Sarek would often stand and watch the moon in thought whenever he had a difficult decision to make. (TOS novel: Sarek)