Venus in Transit across the face of the Sun. I set up a pair of 15×70 Barska binoculars on a tripod, with the morning sun coming through a north-facing window. A shade covered one of the lenses, and the sun was projected on a white wall (not parallel, hence the oval sun). I shot the sun with a digital camera. This setup was good for about ten minutes, and then the binoculars started to smoke. Scratch one pair big binoculars. It was worth it for a twice-in-a-lifetime opportunity (2012, then a hundred year gap). They weren’t collimated anyway.
https://finkh.wordpress.com/2012/06/ for the 2012 transit.