Astronomy Picture of the Day . A Complete Aurora . ... 2.04.1997 . ... U. Iowa ), Polar , VIS , NASA Explanation: Aurora frequently make complete rings around a pole of the Earth. This particular " crown ", visible in orange near the top of this image , was taken by the orbiting Polar spacecraft about one year ago and released by NASA last month. A complete aurora l oval is normally hard to photograph because part of it usually occurs over a brightly sunlit portion of the Earth. ...