Naked eye
Videos
Naked eye, also called bare eye or unaided eye, is the practice of engaging in visual perception unaided by a magnifying, light-collecting optical instrument, such as a telescope or microscope, or eye
Light pollution limits viewing of celestial sights, as in this night scene from Moscow
The Milky Way is visible over the Very Large Telescope, demonstrating clear atmosphere above Paranal Observatory.
Star cluster
Videos
A star cluster is a group of stars, that share an origin, formed at roughly the same time and held together by self-gravitation. Two main types of star clusters can be distinguished: globular clusters
Messier 44, a cluster in the constellation of Cancer
The Pleiades, an open cluster dominated by hot blue stars surrounded by reflection nebulosity
The embedded Trapezium cluster seen in X-rays which penetrate the surrounding clouds
The globular cluster Messier 15 photographed by HST