Hi The issue is that you are trying to view over a heated surface (close to the ground in sunlight). The distortion induced by the "thermals" is enormous. The the target "as viewed" does indeed move around. In the absence of atmosphere and it's issues, the problem would be much easier in a number of ways.
If you were going to do precision optical work at these distances, you would do it over a cool surface at night rather than a hot surface. Bob -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of jimlux Sent: Tuesday, November 02, 2010 9:28 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] A real world project need for timing accuracy... Bob Camp wrote: > Hi > > Ok, I mis-understood the question. > > In my experience, you can have big buck (as in many thousands of dollars) optics and not see .2" holes at 800 yards. The bull's eye is a *lot* bigger than the hole the bullet made. > > 0.2" at 2400 ft is about 0.08 milliradian.. or 0.3 minutes of arc. Your eye can resolve about 1 minute of arc... I'm not questioning your experience, but it seem that even a moderate power scope should allow you to see the holes. As I recall, the Rayleigh limit for resolution is something like 0.7 milliradian/mm of aperture, so 10-15 mm aperture would be in the right ballpark.. I can imagine needing more aperture than 3", though.. you're not interested in resolving a star, but something more akin to separating dots. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
