Think of those old stereoscopes that were popular about 80 - 120 years ago where you had a wooden holder with two almost identical photos placed side by side with a piece of wood separating the two sides so each eye saw a slightly offset image and the mind would create a 3D image out of the two photos. The old 1960's vintage Viewmasters also used this technique to create the same 3D effect as well. Bob -----Original Message----- From: utah-astronomy-bounces@mailman.xmission.com [mailto:utah-astronomy-bounces@mailman.xmission.com] On Behalf Of Julie Clyde Sent: Thursday, September 23, 2010 12:34 PM To: Utah Astronomy Subject: Re: [Utah-astronomy] Do you see stereo? Stupid question.. what is this stereo effect you're all talking about? On Thu, Sep 23, 2010 at 12:30 PM, Daniel Holmes <danielh@holmesonics.com>wrote: