It produces strong molecular maser emission and was one of the first radio masers discovered. Water masers are useful to observe nuclear accretion disks in active galaxies. Observations can be of supernova remnants, masers, gravitational lenses, starburst galaxies, and many other things. The typical isotropic luminosity for these galactic masers is . Rods of synthetic ruby are used to make ruby lasers and masers. At the distances where these masers are found water molecules are disassociated by UV radiation. Additionally, the hydroxyl masers are supported chemical pumping. Hydroxyl, water, and formaldehyde masers are known to exist in these conditions. The radiation amplified by hydroxyl masers is the radio continuum of its host. However, naturally occurring masers lack the resonant cavity engineered for terrestrial laboratory masers. Water and methanol masers are also typical of these environments. Those works led to the completion of the theory of lasers and masers. Early atomic clocks were based on masers at room temperature. Molecular clouds, and especially GMCs, are often the home of astronomical masers. Hydrogen masers are very complex devices and sell for as much as .