Oklahoma on the night of August 14, 2001 and again on August 19, 2001 to observe Mars himself in the 24-inch f/16 Cassegrain telescope. On both nights, neither moon was observed, while fainter stars were observed. If only Phobos were missing and Deimos were present, one might argue that Phobos is a difficult target, and that either the author or his telescope was just not up to the task. However, the author has a personal friend who observed Deimos a few years ago in a 17-inch Dobsonian telescope (but at a higher altitude in the sky). One might also argue that Mars is low in the sky, but the faint stars he observed were just as low.
I was also wrong about Deimos when I published Phobos and Deimos Have Vanished. I sincerely regret that mistake, and I apologize to all of my readers for having made it. Ironically, when I published that mistaken article on August 21, 2000, I had already looked at the photograph that I had taken two days earlier that contained the image of Deimos, but I did not see it at that time. It was not until weeks later that I looked at the same photograph again, and I saw it.