Deep sky objects, beyond our Solar System, have long been popular with amateur astronomers. Observing non-stellar objects such as nebulae and galaxies requires a moonless night and a dark country sky for observation. A large telescope is required to view fainter objects. Magnification is not as important as the size of the mirror or lens of the telescope.

Watching variations in brightness of stars requires many observations over long periods of time (even years) -- an ideal task for amateurs, who are not limited by telescope access or time. Many amateur astronomers monitor active star systems such as novae. Double stars are also observed by amateurs.

Eclipses and occultations (where the Moon or a planet passes in front of a star) allow amateurs to make important measurements of Solar System bodies such as the Moon, Sun and asteroids. By timing such events amateurs have increased the knowledge of asteroids and outer planets. To observe an occultation event one needs to be in the right place at the right time. Amateurs achieve this by observing from home or by mobile expeditions to nearby sites.