Are the colours in the astronomical images real?
Unlike commercial digital cameras, the cameras on research telescopes take greyscale images through filters. These are the images used for scientific analysis. For presentation to the general public, observations through multiple individual filters are often combined to produce colour images. For observations made with visible light, we often try to match the colours that our eyes can see. However, often the light that is observed is invisible to our limited human vision, for example, infrared light, and has to be represented with a visible colour instead. Often the shortest wavelength is represented with blue and the longest with red and this choice of colours is called “chromatic”. Observations through narrowband filters are usually assigned colours in “chromatic order”, although sometimes the ordering is, for aesthetic purposes, not kept chromatic and this leads images known as “enhanced colour images”.
