Originally Posted by CASPER1066:
“If we have a telescope good enough to reach the moon, why cant see pictures of the lunar landing module or anything like that ??..
can someone tell me ?..thanks”
The reason is that it's simply to small to be seen (even with hubble). It would be like trying to read a book that was 30 miles away with some binoculars! It can be shown that it can't be seen with a little maths:
Let's say the largest object on the moon was 5 metres in diameter, I picked 5 because it's a nice round number! The distance to the moon is roughly 384,000 kilometres.
Angular Size = 5 / 384,000,000 = 13 billionths of a Radian
To convert from from Radians to degrees:
In degrees = (1.3 x 10-8) x 180 / Pi = 750 billionths of a degree across
Ok, so we've obtained in degrees the area that we would have to look at to be able to see that particular object, now I will tie this into hubble.
Astronomers use 'arcseconds' instead of degrees. There are 3600 arc seconds in a degree. If we do the maths 750 billionths of a degree x 3600 we get around 0.0026 arc seconds, but because we approximated with the distance I'll round this upto 0.003 arcseconds.
So, I hear you ask? What can hubble see? Our eye can see 60 arcseconds, The best telescope on the ground can see objects 0.5 arcseconds in size, hubble can see more clearly, upto 0.05 arcseconds in size. That makes the moon landing equipment 18 times smaller than what hubble can see. Even if it was 18 times bigger it would resolve to one pixel, to put that in perspective you probably have about 800 thousand pixels on your monitor right now!
Now then, that isn't the only problem! The moon is moving across the sky at 0.5 arcseconds due to it's orbit around earth, you can probably see the problem all ready! It would be like trying to take a sharp picture of a train whizzing by!
I hope this answers your questions,
TNT