n.
Layer of the Sun 's atmosphere, several thousand miles thick, above the photosphere and below the corona .
The chromosphere (literally "colour sphere") is briefly visible as a thin ring, red from hydrogen's emission spectrum, during solar eclipse s when the photosphere is obscured by the Moon. At other times it can be observed only with special instruments. Its temperatures range from about 7,000 °F (4,000 °C) about 700 mi (1,100 km) above the photosphere, increasing with altitude to several hundred thousand degrees. Solar flare s and solar prominences are mainly chromospheric phenomena.