Hi Twiggs, I remember trying to photograph an eclipse of the sun using my Minolta film camera some years ago and with the camera on a tripod by the time I had lined up the camera and set to the highest aperture I noticed this large black area appearing through the SLR viewfinder. The camera's metering never worked after this. Apparently when looking at the sun " wonderful thing hindsight"!!through the camera system the lens path can focus a very hot spot inside the bowels of the camera body. Rather like when we were kids, using a magnifying glass to focus the sun and burn holes in your mates clothing.
I hope no permanent damage has been done to your sensor or mirror Twiggs.
Regards Brian