Night and Day above Almost Planet Sounio . ... Images taken at night compose the top half of the picture , with star trails lasting as long as 11 hours visible. Contrastingly, images taken during the day compose the bottom of the image, with the Sun being captured once every 15 minutes. ... Meticulous planning as well as several transition shots and expert digital processing eventually culminated in this image documenting half of the final two days of last year. ... NASA Official: Jay Norris. ...