Smudge on the Sky - The Gegenschein     Imaged by Rob Ratkowski (photography) on October 14, 2007 under clear dark skies in Hawaii. The gegenschein, the faint elongated smudge against the stars, is produced by a disk of interplanetary dust grains probably extending outwards to the orbit of Jupiter. The grains scatter sunlight in all directions but more strongly directly backwards. The gegenschein or counter glow, opposite the position of the sun in the sky, is the result. The gegenschein is visible to the unaided eye on the darkest clearest nights well away from light pollution. This image conveys its appearance to well dark adapted eyes.   "The guesstimated diameter of the gegenschein is between 6 and 10 degrees.  I really didn't make a angular determination, it was hard enough to se it.  Averted vision brought it out but didn't allow for any real examination of detail, it was there but seemed to blend in with the starfield then pop out and then fade. Elusive but there." Image ©Rob Ratkowski, shown with permission.