Expert: Tom Whiting - 7/18/2006

Question
Hi Tom,

I wonder if would be possible to see the flag on the moon?  Would it feasibly possible to take such an image with a very powerful telescope?  Could NASA silence the conspriacy theorists that say we never went to the moon by taken an image of the flag with Hubble?

It bugs me because you'd think it would be 'easy' to find what with some of the images people can take in their backyard of galaxies, etc.

Thanks for your time!

Answer
Hi Pete,
No, it's a "resolution" problem....you are asking for 5 feet
resolution  (5/5280) or  0.000947 mile resolution, over an average distance of 238,000 miles.  Perhaps if you gave us a mirror (or lens) that is a couple of miles in diameter, then it may be possible...but then again...probably not, because the real limiting factor in resolution is our own wavy atmosphere.

So even with a 10 mile diameter mirror, our atmosphere is
never steady enough to produce a the super-fine resolution
that you are asking for.  In fact, that is the very reason that
the Hubble telescope is up there...to eliminate our unsteady
atmosphere!

Even in a 60 mile high orbit around the moon, all the Apollo
orbital spacecraft could not image the landing sites or
the Rovers and/or landers.....so obviously, even from 60 miles high, 5 foot resolution would be a very difficult task.
For most large Earthbound scopes, a 1 mile diameter crater is about the best we can do on the lunar surface....and the Hubble may achieve 1/4 or 1/8 mile crater...but that's still a far cry from the 5 foot resolution you require.

We can image galaxies because there, you are not dealing
with 5 feet resolution, but rather objects that are hundreds of thousands of light-years in diameter, even though they are millions of light years distant.
It all deals with angular resolution....with a 5 foot flag, you are asking for something like 0.000000000001 arc-second resolution with a lunar flag, whereas most of the bigger, brighter galaxies, photographers are dealing with 20-30 arc-second resolution....just to photograph the entire galaxy.

But note, even with those distant galaxies, we don't image
any individual star in those galaxies...just the combined
fuzz  (light) from those 200 billion stars in the galaxy.
(Any individual star you see on a galaxy image is either
a Supernova in that galaxy, or foreground stars of our own
galaxy.)

Actually, for real proof, all you have to do is remind the
non-believers, that the astronauts left laser reflectors on
the lunar surface for real accurate distance measurements.....
how could we reflect a laser off the moon (which we do all the time) without those permanent laser reflectors, if men had not been there to put them there?  We also placed remote seismometers on the lunar surface to receive info on moon-
quakes, but I believe those don't work anymore, having a
lifespan of only one or two years.
Hope all this helps,
Clear Skies,
Tom Whiting
Erie, PA