Ghostly Sun, 2017 (digital photo)

Creator: Michael Wilkinson This is an image of the sun in Calcium-K light, showing the inner chromosphere. 400 out of 4000 frames are stacked using AutoStakkert!2, sharpened with ImPPG, and added pseudo-colour using curves in GIMP. In the pseudo-colour scheme used, the surface is shown as negative, with the sunspots as bright spots, the area outside the limb is shown in enhanced contrast, highlighting a surge on the western limb, and several small prominences. Despite the sun going into a quieter phase, there is still a lot of activity. Born digital photograph entitled 'Ghostly Sun' by Michael Wilkinson taken in Groningen Province, Netherlands on 4th April 2017. Taken with APM 80 mm f/6 refractor telescope, Vixen Great Polaris mount, ZWO ASI178MM camera, stack of 400 frames. Highly Commended in Our Sun category of Astronomy Photographer of the Year 2017.