Astronomy Picture of the Day

Explanation: This stunning mosiac of the sky around bright stars Antares (Alpha Scorpii) and Rho Ophiuchi reveals spectacular colors in a cosmic starscape. Near the top, Rho Ophiuchi and nearby stars are immersed in blue reflection nebulae - dust clouds that shine primarily by reflected starlight. Cool supergiant star Antares (lower left) is itself shedding the material that reflects the evolved star's yellowish hue. Characteristic of star forming regions, the telltale red emission from hydrogen gas also permeates the view along with dark, obscuring dust clouds seen in silhouette against the background stars and brighter nebulosities. About 500 light-years away, the Rho Ophiuchi star clouds, are well in front of the nearby globular star cluster M4, visible just below and right of center. The view spans about 2 degrees (four full Moons) on the sky.