Antares and Rho Ophiuchi cloud
auteur: Anglo-Australian Observatory/David Malin Images/Novapix
référence: a-neb98-00001
Image Size 300 DPI: 40 * 51 cm
This photograph shows a portion of a great swath of obscuring gas and dust in the constellations Ophiuchus and Scorpius, and illustrates what is probably the most colourful region in the entire sky. The almost garish colours are due to the brilliance and contrasting colours of the stars, by whose reflected light we see the dust clouds. Dominating the picture is the first-magnitude red supergiant star Antares, or Apha Scorpii. Because of its deep red colour the light reflected from the dust has a rich reddish hue, unusual amongst such reflection nebulae which are generally associated with bright bluish stars and normally have the appearance of the nebula surrounding Rho Ophiuchus (top). Clearly to be seen on this picture is the discolouring effect of the dust clouds on the stars and nebulae seen through them: the dust selectively absorbs the blue light leaving the obscured objects with a reddish-brown tinge. Also visible in this extraordinary photograph is the yellowish globular star cluster M4, at 5700 light years (9 times the distance of the foreground dust and stars) the nearest globular cluster to the Sun. Partly surrounding Sigma Scorpii at the right of the picture is a red emission nebula, completing the most comprehensive collection of nebular types ever seen in one photograph. There's also two globular clusters, one of the nearest, M4 at lower centre right and NGC 6144, buried in Antares' haze The photograph was produced by combining 3 separate black and white pictures taken through different filters with the 1.2m UK Schmidt Telescope.