Moondog! The full Moon seen through high cirrus & contrails over Katwijk tonight, leading to this paraselene, the equivalent of a parhelion or sundog as often seen next to the Sun. To the naked eye, moondogs appear white, as they're too faint to activate the colour-sensitive cones. But to a camera, the expected colour is there, due to wavelength-dependent refraction in ice crystals. #AtmosphericOptics 🌈 #Photography 📷 #Astronomy 🌕