I observed a round black object pass in front of the moon through my telescope.

While viewing the full moon through my Tele Vue Genesis-sdf refractor telescope, I saw a small, perfectly round, black object pass over the lunar disk. The object took approximately 10 to 15 seconds to make the transit. The object was in sharp focus, not fuzzy at all. The moon was also in focus at the time. It appeared as if out of nowhere on the eastern edge of the moon, travelled across the moon's face from east to west, then disappeared into the black sky at the moon's western edge. I looked to see if it was visible with the naked eye after it had passed the moon, but it was not. I do not recall exactly which eyepiece I was using at the time, but I am sure the magnification was somewhere in the 30x to 60x range. I am currently 34, and I have been an amateur astronomer ever since receiving my first telescope at age 7. I am thoroughly familiar with the night sky, and I have perfect vision.