Watts are units of radiant flux while lumens are units of luminous flux. Photophores are light-emitting organs which appears as luminous spots on some fishes. Sprites appear as luminous reddish-orange flashes. The streamers look like a bluish 'haze' at the ends of the more luminous leaders. Despite Canopus being vastly more luminous than Sirius, however, Sirius appears brighter than Canopus. B-type stars are very luminous and blue. Fractures of the crust cause starquakes, observed as extremely luminous millisecond hard gamma ray bursts. Mintaka is 90,000 times more luminous than the Sun. It is also one of the most luminous and massive red supergiants. It is around 993 times as luminous as the Sun. It is 375,000 times more luminous than the Sun. Assume that a black hole is surrounded by a disc of luminous gas. Walley-Beckett describes her as at once "luminous", transparent, smart, soulful and emotional. Quasars are believed to be the most consistently luminous objects in the known universe. A 10x50 binoculars is better than an 8x40 for magnification, sharpness and luminous flux.