Averted vision

The crescent moon was about three days young last night, hanging up high in the western sky in the evening twilight. It was just a bit below the Pleiades, and I could see Orion looming to the left (south) and Taurus and the Hyades nearby as well. I love this time of year when the winter stars are setting, what better way to say spring is here? Friday night the moon was too low on the horizon--I've got a lousy view to the west what with the hills and the neighbors and the trees, and Saturday we had a thick, grey layer of clouds obscuring any celestial sights. I stepped out to see Luna when the sky was still blue and then later when it was inky-dark. I noted that if I looked directly at the moon the Pleaides would fade away, and then when I looked askance at the whole scene the cluster seemed to jump out into my field of view. This technique of averted vision is well-known to skygazers and astronomers, and takes advantage of the fact that the light-gathering capabilites of the eye are somewhat off-center. (Here's a couple of links that go into more detail.)

The Latin verb verto (principal parts: verto, vertere, verti, versum) means "turn," and the related compound averto (-tere, ti, -sum) is, obviously, "turn away." The past participle of verto is the familiar versus, which has come to mean "against," in the sense of "opposed to" in English. (WordMan™ strikes again!)