Originally posted by wmd_2008
Originally posted by golemina
Let's rent some of the REAL WORLD optical systems 100 inch, 200 inch, Hubble anyone?
Why do you think the Hubble would help you?
From one of my posts earlier today.
The resolving power of the Hubble is 0.05 arc seconds or 0.0000138888888889 deg at the distance of the Moon that's about 305 ft.
Also how do you work out the Moons gravity as you claim it to be
I've seen this asked a lot in different ways:
"Why can't the Hubble Space Telescope see the moon landings?", "We have huge telescopes here on Earth, why can't they see the moon landings?"
More often than not the reasoning behind wondering this is due to the amazing detail that Hubble gives us in the images that it takes of other
celestial objects that are much further away than the moon, so why can it not do the same thing for the moon?
The reason that it can't comes down to basic math. If you have two objects of the same size, but one is further away than the other, the one further
away will look smaller, even though it is not really smaller.
A telescope is not a magnifying glass. It works differently because it has a mirror that gathers light and focuses it to a point on either an eye
piece or a camera.
By knowing the size of the mirror, you can calculate the amount of resolution a telescope has, which is normally measured in arcseconds.
There are 3600 arcseconds in 1 degree. A full moon seen by you is 1800 arcseconds, so as big as it looks in the sky, it's only 1/2 a degree wide.
The formula R=11.6/D is used to figure out resolution, with R being the resolution in arcseconds and D being the diameter of the primary mirror.
Hubble's mirror is 2.4 meters wide, or 240 centimeters. 11.6/240 = 0.05
So Hubble's resolution is 0.05 arcseconds. That's a really good resolution. It means you could see a 6 foot wide object from 8000 feet away.
However, we have to take into account the size of an object and how far away it is. This will tell you if your telescope can see that object that is
at that distance or not. The formula we use for that is:
Where "d" is the diameter of the object. "D" is the distance of the object, and "a" is the size in arcseconds.
The bottom part of the LEM is about 4 meters. The distance to the moon is about 400,000,000 meters.
The LEM bottom would be around 0.002 arcseconds. So in other words: it's too small of an object too far away to be seen by Hubble due to the fact
that Hubble's absolute minimum resolution is only 0.05 arcseconds.
The beautiful nebulas and galaxies we see in the Hubble images are much, much further away....but their size is also part of the equation: they are
also LIGHTYEARS in size. So yes, they are further away from the moon, but their size is much, much, much bigger than the moon, and that helps
determine the resolution.
If there was a huge football stadium on the moon, it would look like a dot to Hubble.
If you want Hubble to see the LEMs then you're going to need to change it's mirror out from the 2.4 meter one, to a mirror that is over 100 meters
So why does the LRO see the LEMs?
Because it's orbiting the moon itself, and is much, much closer than Hubble. So even though it's mirror in it's telescopic equipment is much
smaller than Hubbles, the fact that it's looking at that stuff from only tens of kilometers away changes everything.
So again: it all comes down to math.