A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Tony Oz
Date: 2018 Apr 1, 14:50 -0700
You suspected a second window on the other wall of a room where that double-sun video was taken. That is unrealistic I think - the person filming the video would block the reflection.
I do not know how american windows are made - here in Russia we have double- or even tripple-glassing in our windows. That explains the artifact just nicely.