Rarely an asteroid will pass so close so as to be visible. If you can get your hands on a Hydrogen-alpha solar telescope you will, be able to see prominances that change over a period of hours. The sun is changing and on a small scale it does change on the scale of minutes, but it is hard to see any movement at that scale with basic equipment. This was created by the formation as a massive early star collapsed to a black hole producing a jet of energy that happened to point our way. If you had happened to know exactly where to look you could, (marginally with the naked eye, but easily with binoculars) have seen the optical counterpart to the gamma-ray burst. It gave a flash of gamma rays that lasted a little over a minute. Pulsars are too dim to be seen with normal equipment even the bright nearby crab pulsar has a magnitude of 16.5 (and at one flash in 33 milliseconds, it is too quick to see by eye) It isn't quick enough to notice the change in the moment, but it is quite clear if you are observing over a few hours. Similarly, Algol will fade from magnitude 2 to 3.5 over a few hours. The moons of Jupiter do move notably during the night, and when one moves into or out of shadow, it can appear or disappear over the course of a couple of minutes: easily noticeable.ДЄ supernova could brighten quickly enough for the variation to be visible over a night's observation: You wouldn't see it suddenly appear, but over the course of a night it could appear brighter at the end of the night than at the beginning. But because they 'come from space' and occur well above the clouds they are often considered to be part of astronomy.ДЄs you note, eclipses and occultations happen quickly enough for the changes to be visible. There are only a few exceptions to this: Meteors are an atmospheric phenomenon, and a meteor will appear to move rapidly across the sky. If it moves or flashes it isn't astronomy, it is meteorology or technology.

Active sky 16 cloud shading flickering