Looking through the Dark Cloud B68

B68 is a dark cloud situated at a distance of about 500 light-years (160 pc) towards the southern constellation Ophiuchus (The Serpent-holder). This is a false-colour, infrared composite photo of the dark cloud Barnard 68, obtained on March 8-9, 1999, with the SOFI instrument at the ESO 3.5-m New Technology Telescope (NTT) at La Silla. Three exposures were made through J- (wavelength 1.25 µm - 3 min; here colour-coded as "blue"), H- (1.65 µm - 30 min; "green") and Ks-filters (2.16 µm - 30 min; "red"), respectively. The "reddening" of the background stars that are seen through the cloud is very obvious. It is due to the larger obscuration in shorter wavebands. The sky field measures about 4.9 x 4.9 arcmin 2 (1024x1024 pixels). A slight mismatch between the individual frames is present in the upper corners; this is caused by atmospheric effects. The pixel size is 0.29/arcsec. North is up and East is left.