The first Gaia sky map in colour

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, G_BP and G_RP 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 G_RP, G and G_BP maps are then used as R, G, and B channels respectively, combined and post-processed to create a coloured image.

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