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it just isn't physically possible to resolve a flag on the surface of the moon with anything less than 3.5 mile diameter telescope. The technology used can't he

by borism 16y ago

it just isn't physically possible to resolve a flag on the surface of the moon with anything less than 3.5 mile diameter telescope. The technology used can't help much with physically impossible things!

idm 16y ago
I don't know much about this topic, but I did RTFA, so permit me to ask a stupid question: 1. if this impossibility is related to noise overwhelming the image signal (thereby causing it to be an unresolved blur) 2. and if we assume that this 3.5-mile diameter is for a naked eye looking through a telescope (i.e. we're talking about a single exposure) 3. isn't there some statistical process that could enable a reduction of the diameter of the lens, which would reconstruct a less-noisy image based on multiple exposures?
mrb 16y ago
It is perfectly possible to resolve a (6-foot) flag with a telescope. The article states "the Earth's atmosphere is never steady enough to allow resolution below about one arc second for most locations". But according to the European Southern Observatory one can do 1000x better: "With AMBER on the Very Large Telescope Interferometer (VLTI), the astronomers were able to see details on the scale of one milli-arcsecond, corresponding to being able to distinguish, from the Earth, the headlights of a car on the Moon." -- http://amber.obs.ujf-grenoble.fr/spip.php?article154 http://amber.obs.ujf-grenoble.fr/spip.php?article154 Therefore a 6-foot-wide flag ("headlights of a car") would be visible as 1 or 2 pixels with the VLTI, which is made of four 8.2 meter reflectors. I presume the actual flag left by the astronomers was somewhat smaller, so one would need a tad better telescope, but certainly not something with a "3.5 mile diameter". Upvote me. HN readers need to be educated :-)
- borism 16y ago
  yes, but the article explicitly defines "flag being visible" as stripes of the US flag being visible. for that you would need a tad better than 6-foot resolution.
  - mrb 16y ago
    Fair enough. On a side node, the VLTI should be able to produce a 2x2 or 3x3 pixel image of one of the russian or american lunar landers (14-foot wide). It would be a cool thing to accomplish to demonstrate the resolution of the VLTI...

by borism 16y ago

idm 16y ago

I don't know much about this topic, but I did RTFA, so permit me to ask a stupid question: 1. if this impossibility is related to noise overwhelming the image signal (thereby causing it to be an unresolved blur) 2. and if we assume that this 3.5-mile diameter is for a naked eye looking through a telescope (i.e. we're talking about a single exposure) 3. isn't there some statistical process that could enable a reduction of the diameter of the lens, which would reconstruct a less-noisy image based on multiple exposures?

mrb 16y ago

It is perfectly possible to resolve a (6-foot) flag with a telescope. The article states "the Earth's atmosphere is never steady enough to allow resolution below about one arc second for most locations". But according to the European Southern Observatory one can do 1000x better: "With AMBER on the Very Large Telescope Interferometer (VLTI), the astronomers were able to see details on the scale of one milli-arcsecond, corresponding to being able to distinguish, from the Earth, the headlights of a car on the Moon." -- http://amber.obs.ujf-grenoble.fr/spip.php?article154 http://amber.obs.ujf-grenoble.fr/spip.php?article154 Therefore a 6-foot-wide flag ("headlights of a car") would be visible as 1 or 2 pixels with the VLTI, which is made of four 8.2 meter reflectors. I presume the actual flag left by the astronomers was somewhat smaller, so one would need a tad better telescope, but certainly not something with a "3.5 mile diameter". Upvote me. HN readers need to be educated :-)

borism 16y ago
yes, but the article explicitly defines "flag being visible" as stripes of the US flag being visible. for that you would need a tad better than 6-foot resolution.
- mrb 16y ago
  Fair enough. On a side node, the VLTI should be able to produce a 2x2 or 3x3 pixel image of one of the russian or american lunar landers (14-foot wide). It would be a cool thing to accomplish to demonstrate the resolution of the VLTI...