International Ultraviolet Explorer was considered the most successful astronomical satellite ever. The human eye can perceive light with wavelengths between roughly 350 (violet) and 700 (red) nanometres. Ultraviolet light has wavelengths between roughly 10 nm and 350 nm. UV light can be harmful to human beings, and is strongly absorbed by the ozone layer. This makes it impossible to observe UV emission from astronomical objects from the ground. Many types of object emit copious quantities of UV radiation, though: the hottest and most massive stars in the universe can have surface temperatures high enough that the vast majority of their light is emitted
Ultraviolet photography about 180 nm. UV photographers subdivide the near UV into: (These terms should not be confused with the parts of the radio spectrum with similar names.) There are two ways to use UV radiation to take photographs - reflected ultraviolet and ultraviolet induced fluorescence photography. Reflected ultraviolet photography finds practical use in medicine, dermatology, botany, criminology and theatrical applications. Sunlight is the most available free UV radiation source for use in reflected UV photography, but the quality and quantity of the radiation depends on atmospheric conditions. A bright and dry day is much richer in UV radiation and is preferable