This image is not a photograph. The map is a map of the measured brightness, or flux, of the almost 1.7 billion sources in Gaia DR2. It is a combination of three other maps, separately compiling the fluxes measured in the Gaia G, GBP and GRP photometric bands (see "Gaia Data Release 2" and "Blue and Red Photometers"). These individual maps are built by adding, or integrating, the flux of all sources that fall within each pixel. A logarithmic rescaling is applied to compress the huge range of integrated brightness throughout the sky. The GRP, G and GBP maps are then used as R, G, and B channels respectively, combined and post-processed to create a coloured image.
Download large version of the image. (620 KB, PNG)
Page last updated: 02 May 2018