This image is a three colour composite of the well-known Crab Nebula as observed with the FORS2 instrument in imaging mode in the morning of November 10, 1999.
In this picture, the green light is predominantly produced by hydrogen emission from material ejected by the star that exploded. The blue light is predominantly emitted by very high-energy ("relativistic") electrons that spiral in a large-scale magnetic field (so-called syncrotron emission).
Technical information: This photo is based on a composite of three images taken through three different optical filters: B (429 nm; FWHM 88 nm; 5 min; here rendered as blue), R (657 nm; FWHM 150 nm; 1 min; green) and S II (673 nm; FWHM 6 nm; 5 min; red) during periods of 0.65 arcsec (R, S II) and 0.80 (B) seeing, respectively. The field shown measures 6.8 x 6.8 arcmin and the images were recorded in frames of 2048 x 2048 pixels, each measuring 0.2 arcsec. The Full Resolution version (available from ESO's site, below) shows the original pixels. North is up; East is left.
This is an enlargement of a smaller area in the center of above image. The pulsar has been identified with the lower/right of the two close stars near the geometric center of the nebula, immediately left of the small arc-like feature.
Last Modification: 13 Jul 2000 23:30 MET