Dear Robert, I like your appraisal and your suggested experiment. Thank you for your valuable contribution. Steven and I will attempt to carry out the experiment one night soon, God willing. Any thoughts on the direction/navigation issues re Apollo? Neville. Robert Bennett <robert.bennett@xxxxxxx> wrote: The analysis of Mars observations using the human eye physiology cited below would benefit by noting the following: 1.. The study was done for vision of Mars with one eye. The use of two eyes would have a baseline of about 2 1/2 inches, with proportionally greater resolution than the size of the fovea. Theoretically assessing the resolution capability of the optic chiasm in synthesizing the two optical signals from each eye is not presently possible. 2.. There are tremors/oscillations in the humour of up to 90 hertz in frequency and of 1 or 2 photoreceptor amplitude. Their purpose is not well understood but believed to be an aid to binocular focussing. Sampling theory predicts that these tremors could theoretically improve resolution by as much as 40 times! But again the reality of the black box nature of the chiasm again thwarts a complete analysis of human vision resolution. A question is well raised, due to the uncertain abilities in the optic pathway : Why not duplicate the Mars observation by the unaided eye with a terrestrial simulation, to confirm/disprove whether the eye can discern Mars if the standard solar system scale is used? Let a white disc the size of a US dime (18 mm) be colored to mimic the reflectance spectrum of Mars, and be illuminated to reflect the same intensity of Mars radiation seen from Earth. 20 arc secs is about 9.7 * 10^-5 rad, so the dime should be placed about 186 m. or 203 yds. from the observer. Under dark conditions at a distance of about 2 football fields, this simple experiment based on the scientific method of Aristotle and Bacon should verify if the Mars data is consistent. That is, can the dime be seen with the unaided eyes or not? AMDG, Robert --------------------------------- ALL-NEW Yahoo! Messenger - all new features - even more fun!