Mr. Q. (and the Davids): You probably read a piece I wrote for Astronomy back in the early 80s, or a similar piece for S&T in the 90s. I've observed Jupiter using this technique several times since the 70s. I personally have never observed Mars with the unaided eye in the daytime, but I think it does get bright enough, so there is a chance. In fact I had a correspondent in Saudi or Kuwait who apparently did see Mars, naked eye, with the sun still in the sky seveal years ago. I think he did use binoculars to find it initially, though.

By the way, there are a series of opportunities to see Jupiter in the morning sky over the next few months, beginning with the Last Quarter at the end of March (actually it is closest to Jupiter on the 2nd of March). If you are an early riser, it may be worth the try!

Larry Sessions
Denver