Letters from the December 15, 2007, issue of Science News
By Science News
Fuzzy logic
Astronomer Masanori Iye of the National Observatory of Japan blames the blurry appearance of meteor trails at about 100 kilometers altitude on the fact that they were photographed with telescopes focused at infinity (“Out-of-focus find,” SN: 9/29/07, p. 205). But optics teaches that any object much farther away than the focal length of the telescope is essentially “at infinity.” Wouldn’t a routine cause of fuzzy telescopic images—diffraction—be a more important reason for the blurred trails?