Inverted colours of the boundary between Mare Serenitatis and Mare Tranquilitatis, 2017 (digital photo)

Creator: Jordi Delpeix Borrell In standard pictures of our Moon, we usually pay attention to well contrasted details. Our eye usually looks at the craters and mountains. The seas on the other hand are not very contrasted, and therefore we don't pay much attention to them. Inverting the image is a legacy of deep sky imaging, where tenuous extensions of galaxies and nebulae can be more visible on a negative image because our eye more easily detects tenuous dark details on a white background. This is also useful in Moon imaging helping to reveal otherwise barely detectable soil features such as ray systems. Low contrast areas like the lunar seas and ray systems, looks much more interesting because low contrast details are revealed. Born digital photograph entitled 'Inverted colors of the boundary between Mare Serenitatis and Mare Tranquilitatis' by Jordi Delpeix Borrell taken at L'Ametlla del Vallès, Spain on 6th December 2017. Taken with Celestron 14 telescope, Sky-Watcher NEQ6 Pro mount, ZWO ASI 224MC camera, 4.200 mm, f/12. Winner of the Our Moon category of Astronomy Photographer of the Year 2018.