Astronomy Picture of the Day

Explanation: This premier gamma-ray view of the sky was produced by the COMPTEL instrument onboard NASA's orbiting Compton Gamma Ray Observatory. The entire sky is seen projected on a coordinate system centred on our Milky Way Galaxy with the plane of the Galaxy running across the middle of the picture. Gamma-ray intensity is represented by a false colour map - low (blue) to high (white). COMPTEL's sensitivity to gamma-rays which have over 1 million times the energy of visible light photons reveals the locations of some of the Galaxy's most exotic objects. The brightest source, the Crab pulsar, is located near the plane of the Galaxy on the far right. Moving along the plane from the Crab, more than halfway toward the galactic centre, another bright gamma-ray source, the Vela pulsar, appears. The galactic centre itself, along with the famous black hole candidate Cygnus X-1 (near the plane, halfway from the centre to the left edge) are also seen as bright sources. Both above and below the plane, spots of gamma-ray emission due to distant active galaxies are also visible.