posted on Mar, 8 2005 @ 11:53 AM
"That is a good idea about hubble , but do we know we are still aligned correctly or will they find nothing because they dont have the right
coordinates, that would just put us back to where we are now , someone with dummied up photos or real photos thought to be dummied."
It doesn't matter. The reason we cannot see the lunar lander or the soviet robotic landers is that the HST does not have a wide enough aperture.
Theoretical resolving power (that is being able to determine one thing from another, like the lander from the ground) is driven by what's called the
Rayleigh criterion. It is an equation that says the theoretical lower size limit of something you can see is based on the aperture of the
viewing device (~5 mm for your eye's pupil; ~2.4 m for the HST), the distance to the object, and some other derivatives. for those of you who are
interested, it is:
Rt = (1.22 X w X A) / Do,
Rt is the theoretical resolution (how small something can be and still be seen as something different);
1.22 is a conversion factor;
w is the wavelength of light (say 600 nm for visible spectrum);
A is aperture;
Do is distance to the object.
If you plug in the numbers, the smallest thing we could see on the moon (given perfect eyes with a pupil diameter of 5 mm) and perfect viewing
conditions would be an object 55.6 km across.
With the HST, given its aperture of about 2.4 m, the smallest thing you could see on the moon (and of course, in space the conditions are much better)
is about 115 meters.
This means you could point HST at the Moon and see something about as big as a football stadium, but it'd still only be a dot.
Remember, the resolving power isn't driven by the magnification; once you get past the Rayleigh Limit, the extra magnification doesn't mean
Resolving power is driven by the wavelength of light as well. If you used radio waves, UV, IR, or X-rays, you'd get more or less capability, but not
all that much. And then you'd have to convert the image using special film!
If anyone here has Microsoft Excel, I just put together a spreadsheet that allows you to enter an aperture and a distance, and you can find how small
something can be and still be seen.
U2U me, and I will be glad to send it to you.