In a previous article, I posted pictures taken by my friend Phil of the Orion Nebula and hypothesized that they were of a geosynchronous satellite. Afterwards, I posted a plea on sci.astro.satellites.visual-observe, and got a very nice response from Ed Cannon (who also took the trouble to post here, but I missed it! Doh!) identifying it as the Canadian communications satellite
Anik F1. It’s position and magnitude estimates seem right on the money to me. It’s a big sucker, with its solar cells unfurled it measures over 132 ft by 29.5 feet. .

Belated thanks to Ed Cannon!