To accurately identify the dark spot you observed, I would need more details such as the location, time, and date of your observation.
However, in general, there are various objects or phenomena that could appear as dark spots in the night sky. Some possibilities include:
Cloud cover: If there were clouds blocking your view, they could have appeared as a dark spot obscuring the stars or other celestial objects.
Light pollution: If you were observing from an area with significant light pollution, it may have created a dark region in the sky, as the artificial lights can mask the visibility of stars.
Celestial bodies: Depending on the time and location of your observation, certain celestial objects such as planets, stars, or galaxies might have been visible as dark spots against the background of the night sky.
To accurately determine what the dark spot was, it's best to consult astronomical resources, star charts, or planetarium software that can provide specific information based on your observation parameters. Additionally, local astronomical societies or clubs can also offer expertise and help identify celestial objects based on your description.