IAU COMMISSION 21
LIGHT OF THE NIGHT SKY / LUMIERE DU CIEL NOCTURNE
President: Stuart Bowyer
Vice President: Phillippe Lamy
Organising Committee: S. Bowyer (USA), E. Dwek (USA), Bo A. Gustafson (USA), M. S. Hanner (USA), P. Lamy (France), A-.Ch- Levasseur-Regourd (France), J. S. Mikhail (Egypt), I. Mann (Germany), T. Mukai (Japan), T. Matsumoto (Japan).
The diffuse components of the light of the night sky encompass a variety of physical phenomena over the full range of cosmic distance scales. From the Earth outward they include airglow in the Earth's atmosphere, scattering and thermal emission from the interplanetary dust cloud (zodiacal light), emission from the interstellar medium, integrated starlight, diffuse galactic light, and diffuse emission in other galaxies and extragalactic background radiation. The purpose of Commission 21 is to facilitate research in these areas among the worldwide astronomical community. The Commission sponsors colloquia and symposia on these topics and supports related efforts in other commissions in the IAU. For historical and programmatic reasons, the Commission's main emphasis is in the ultraviolet, optical, and infrared bands of the spectrum.
Commission 21 is part of Division III, Planetary Systems Science, which also includes Commissions 15, 16, 20, 22, and 51.