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Kelly Johnson
2003-Jun-29, 07:45 PM
Hi All,

Surfing the internet, I came across this site:


http://www.geocities.com/telescope1999/14-5inch.html

And it got me wondering. With a big enough telescope, could we see the lunar landers from earth?

Thanks,
KJ

kilopi
2003-Jun-29, 08:01 PM
Not yet (http://www.badastronomy.com/phpBB/viewtopic.php?p=79378#79378).

Vega115
2003-Jun-29, 08:30 PM
couldnt we use Hubble thought? I mean, it sees LIGHT YEARS out into the universe....it should be able to see the lunar landings (the part that stayed on the moon) right? :-?

Chip
2003-Jun-29, 08:30 PM
Thats a nice telescope in the link you posted.

There are no Earth based telescopes that can see the Apollo remaining lander platforms on the moon. The Hubble Space Telescope is not designed for viewing the moon that closely either.

I recall seeing pictures perhaps from a lunar orbiter that claim to show the shadows of the landers on the lunar surface. I can't find these via Google now, but if anyone knows about them, please link to them here. :wink:

Irishman
2003-Jun-29, 09:35 PM
This question pops up frequently on the Apollo Hoax forum. I guess someone really should write up a FAQ on this topic. Maybe I'll suggest it to JayUtah for Clavius.

As far as I know there are no telescopes with the optical resolution to pick out the Apollo landers. Recently, there was some discussion of the very latest generation in optical interferometer telescopes using adaptive optics and such that was going to try to look at the landing sites, mostly to see just how fine they could pick things out. I believe they were actually hoping to pick up the shadows from a low sun angle, rather than the landers themselves.

The Hubble Space Telescope does not have the ability to see that fine a detail on the surface of the Moon. The smallest resolution ability the Hubble has is about 200 m/pixel (IIRC). You can see how it would be difficult to pick out an object the size of a Chevy Suburban.

But wait, how can Hubble see so far away then? The answer is twofold. Primarily, the objects being viewed by Hubble may be very far away, but they are also huge. You're talking about viewing galaxies that look like dots on the image. Second, picking up stars on the black background is different than picking up images on a bright background. Hubble is set with very long exposure times, allowing light to collect for long periods of time. This allows very faint light sources to show up against the blackness of space. Even if the star is not large enough to produce a visible disk (i.e. a resolvable image size), photons will be collected and trigger the pixel to show up. The contrast of light against no light is easier to detect than separate grays on a saturated image. Or something like that - I'm not sure how Hubble collects the image - I know it is converted to data for transmission to Earth, and nobody sees a direct image from the scope's mirrors.

Still, it would be cool to have a scope that could pick them out. Someday....

Comixx
2003-Jun-29, 10:10 PM
Here's the site (http://www.tass-survey.org/richmond/answers/lunar_lander.html) that show pictures of the Apollo hardware on the surface of the Moon. A couple from the CSM, and then a couple from Clementine, a satellite that was sent to map the moon. The top of the page has a description of why no Earth-based scopes can image the moon.

Peter B
2003-Jun-29, 11:47 PM
couldnt we use Hubble thought? I mean, it sees LIGHT YEARS out into the universe....it should be able to see the lunar landings (the part that stayed on the moon) right? :-?

Think of it this way: you can see a large building which is kilometres away, but you can't see an ant 100 metres away.

Just because one object is closer to you than another, doesn't mean it's easier to see than the more distant object.

man on the moon
2003-Jul-08, 04:55 AM
all the above are true, and i'm going to add one more. i will say now that i don't know the specs of hubble, but i'm willing to bet the focal plane is not set to view the moon. cameras are not like our eyes in the regard that they cannot focus on anything they please. they are limited by the Fstop(shorthand for the size of the camera's "iris"). the smaller the Fstop, the larger the plane of focus, the larger the opening, the less depth of field you will get. i would be willing to bet the HT is set to focus on said distant objects, and even if the lens speed was recalibrated, it would not be able to focus well enough to make out any more than a vague white spot of the moon.

wedgebert
2003-Jul-08, 05:16 AM
Don't forget that compared to the distant galaxies, the moon is racing along. Ever try to use binocs or a telescope to watch a moving object? It's very hard to keep it in your field of view, Hubble would suffer the same problem watching the moon.

The Bad Astronomer
2003-Jul-08, 05:22 AM
I get this question a lot. So often I wrote a FAQ for it:

***
Hi! You asked about using a telescope to look at the Apollo
landing sites. That's a reasonable idea, but unfortunately
it won't work. The problem is resolution. There is an upper limit
to how well a telescope can see objects depending on their size.
Even for Hubble, at the distance of the Moon it cannot clearly
see objects less than about 100 meters across. Nothing we left
on the Moon is anywhere near that big, so all you would see is a
collection of dots, which would prove nothing!

There is a way, though: wait for the local sunrise or sunset at the
landing site. That way, the lunar module would cast a long
shadow, possibly long enough to see. That wouldn't prove anything,
but it lends support. Still, I doubt Hubble will ever do this.
Time on Hubble is hotly fought over (see
http://www.badastronomy.com/bad/misc/badhst.html) and I don't see
the people running the 'scope letting someone use up precious
time to prove that we went to the Moon, when no scientist seriously
doubts it in the first place! It might be possible to do this from the
ground, though. I would need to think about it and figure out if the
shadow is really visible or not. It's a neat idea.

I plan on writing this up at some point and putting it on my site.
I will also be doing a more complete debunking of the hoax theory
at some point, but it will have to wait a while. I have a long list
of things to do!

***

Hubble has observed the Moon (http://hubblesite.org/newscenter/archive/1999/14/), by the way. The Moon is not too bright, as some have said; it's just hard to aim it at something moving so quickly. I wrote about this in my book, too.

man on the moon
2003-Jul-08, 12:34 PM
i stand corrected! at least i think i do...you are saying hubble can't resolve anything under 100 meters, this seems like more of an issue with focal length (i.e telescopic lens vs. fish eye lens, no pun intended :D) than with the Fstop...am i correct in this? the hubble is either more versatile than i first realized or cameras don't follow the rules my photography teacher taught me last fall!
as far as the moon speeding along...tha makes a lot of sense. it's hard to track a bird at your feeder with binocs as opposed to one across a field...same idea hubble right?

incidentaly, to avoid any more faux pas, is there somewhere that lists the specs of what hubble is capable of? i like to avoid being wrong as much as the next guy, and research can help squell that.

Kaptain K
2003-Jul-08, 03:14 PM
Resolution is purely a function of objective element diameter. The larger the mirror (or lens), the better the resolution. This is one of the two reasons why bigger is better. The other is light gathering power. Resolution is a linear function. Double the diameter, double the resolution Light gathering power goes up with the square of diameter, since it is a function of the area of the objective element.

man on the moon
2003-Jul-09, 05:18 AM
well what'da ya know? and all this time i've thought a telescope was essentially a big tele-photo lense with some cool magnifiers and mirrors attached. you learn something everyday!

The Bad Astronomer
2003-Jul-09, 06:59 PM
Resolution is purely a function of objective element diameter.

... at a given wavelength. HST's resolution is about 0.1 arcseconds at 5000 Angstroms, but is slightly better in UV and worse in IR. That can be improved using sophisticated techniques, but that's the usual number quoted.

ToSeek
2003-Jul-09, 07:31 PM
incidentaly, to avoid any more faux pas, is there somewhere that lists the specs of what hubble is capable of? i like to avoid being wrong as much as the next guy, and research can help squell that.

This is the best I've come up with. (http://pao.gsfc.nasa.gov/gsfc/service/gallery/fact_sheets/spacesci/hst3-01/introduction.htm#config) (Scroll down a little.)

man on the moon
2003-Jul-10, 06:49 AM
cool. thanks

Kaptain K
2003-Jul-10, 11:05 AM
well what'da ya know? and all this time i've thought a telescope was essentially a big tele-photo lense with some cool magnifiers and mirrors attached. you learn something everyday!
Better to think of it as a telephoto lens is a telescope with a camera attached to it.

Hamlet
2003-Jul-10, 01:16 PM
i stand corrected! at least i think i do...you are saying hubble can't resolve anything under 100 meters, this seems like more of an issue with focal length (i.e telescopic lens vs. fish eye lens, no pun intended :D) than with the Fstop...am i correct in this? the hubble is either more versatile than i first realized or cameras don't follow the rules my photography teacher taught me last fall!
as far as the moon speeding along...tha makes a lot of sense. it's hard to track a bird at your feeder with binocs as opposed to one across a field...same idea hubble right?

incidentaly, to avoid any more faux pas, is there somewhere that lists the specs of what hubble is capable of? i like to avoid being wrong as much as the next guy, and research can help squell that.

Here (http://hubblesite.org/sci.d.tech/nuts_.and._bolts/) is another link that explains how Hubble and its subsystems work.

man on the moon
2003-Jul-11, 06:25 AM
all the above are true, and i'm going to add one more. i will say now that i don't know the specs of hubble, but i'm willing to bet the focal plane is not set to view the moon. cameras are not like our eyes in the regard that they cannot focus on anything they please. they are limited by the Fstop(shorthand for the size of the camera's "iris"). the smaller the Fstop, the larger the plane of focus, the larger the opening, the less depth of field you will get. i would be willing to bet the HT is set to focus on said distant objects, and even if the lens speed was recalibrated, it would not be able to focus well enough to make out any more than a vague white spot of the moon.

good greif do i feel like an idiot! :oops: will someone please slap me before i go completely nuts? i should know better! for some reason though i was thinking the HST was just a really big camera up in orbit... :P
of course i know the difference between a camera lense and a telescope...apparently my brain likes to make me a fool sometimes (ok, a lot of times). #-o

my sincerest apologies to anyone i may have confused or irritated.

*tries to pull foot out of mouth only to find it quite secure in its new home*

thanks for the links though, they are still quite fascinating! (and informative)

Kaptain K
2003-Jul-11, 10:59 AM
i should know better! for some reason though i was thinking the HST was just a really big camera up in orbit...
But, that is exactly what it is! 8)

man on the moon
2003-Jul-11, 03:34 PM
*takes head out of sand*

you know what i mean...it's a telescope with a camera (cameras? what's the correct way of putting that here...a camera with lot's of settings? :-? ) on board. the scope itself isn't a lens with a changeable aperature and a shutter. it's a tube with several mirrors that bounce and focus the light to an eyepiece that actually houses the camera...roughly put.

unless i'm wrong about being wrong that is. that doesn't happen very often! (and this aint one of those times...)

*buries head in sand again, still rather embarresed :oops: *

Kaptain K
2003-Jul-11, 05:34 PM
man on the moon,

The thing is that Hubble is a camera. There is no eyepiece (and no way to get there to look through it if there were). Actually, most (if not all) professional telescopes are cameras, since the pros don't look through them. They take photographs or spectra or other measurements. Only amateurs actually look through telescopes! 8)

man on the moon
2003-Jul-12, 11:21 AM
:-? :o :-? :o :-?

that clears it up a bit. i should say, "camera instead of eyepiece". still, i'm not certain if you mean that it is just a huge camera (ie-a long barrel with a focusing lens, a leaf aperature, and a shutter) or a telescope (a long barrel, with a focusing lense, a reflecting mirror inside, another reflecting mirror or two, and then the camera.) if the HST has an aperature setting (Fstop) in the optic line before it gets to the processing center, that is pretty impressive. a hybrid maybe?

it isn't very often that i'm wronger (more wrong?) when i correct myself than i was in my original statement! someone please clarify if you know more exactly. this is going to drive me crazy... :x

Kaptain K
2003-Jul-12, 04:54 PM
Hubble is a camera in the literal sense. It is a device for making images. There is no "iris". It is wide open all the time. The aperture is fixed. The f/ratio is fixed. The focus is fixed (infinity). Hubble has several different instruments for different types of observations. To use a given instrument, it is moved into the light path.

man on the moon
2003-Jul-13, 02:53 AM
ahh! now i understand. thank you! (hope this helps you too kelly!)

iwcarinae
2003-Jul-15, 01:36 PM
The thing is that Hubble is a camera. There is no eyepiece (and no way to get there to look through it if there were). since the pros don't look through them. They take photographs or spectra or other measurements. Only amateurs actually look through telescopes! 8)[/quote]

Do you really believe that? When I was a pro, I had to look through the telescope, just to see if the star I was observing was on the cross wires, and observers of doublestars also do visual observations, on the other hand, many amateurs use CCD-camara's nowadays

tracer
2003-Jul-15, 11:55 PM
Forget the Hubble Space Telescope.

Anybody remember the Clementine mission?
It was an Air Force project that sent a space probe to the moon in the mid-1990s to test out some spy-satellite technology.

Even from Lunar orbit with spy satellite cameras, Clementine still didn't have enough resolution to make out any equipment left at the Apollo 11 landing site!

If we can't see it from a few hundred kilometers away, we're sure as heck not going to be able to see it from 400,000 kilometers away here on Earth.

Archer17
2003-Jul-16, 02:06 AM
A top-of-the line U.S. spy satellite in lunar orbit would detect the Apollo 11 site. The full capabilities of our real spy satellites aren't public knowledge, Clementine notwithstanding.

Taks
2003-Jul-16, 02:31 AM
i believe the resolution drops with the square of the distance (corrections welcome) so a spy satellite orbiting the earth at 250 miles that has a resolution of say, 3 inches, would be (24,000/250)^2 times worse which equates to 9216 time worse or 27,648 inches of resolution from a LEO orbit. granted, the 250 mile # is probably a generalization they may be a tad higher (not much).

mark

Taks
2003-Jul-16, 02:40 AM
a better method would be some sort of synthetic aperature radar i think. you could take multiple "pictures" across a very wide swath of space and use some sort of interferometer technique to combine the images into the objects. this would be very hard to do with two objects moving wrt each other as an orbiting satellite and the moon would be doing. the theoretical limit would then be the wavelength of the radar (plus maybe some processing gain improvements, not sure about the math there, however). at 30GHz that would be 1cm.

any other thoughts from the gallery?

mark

Kaptain K
2003-Jul-16, 11:04 AM
Do you really believe that? When I was a pro, I had to look through the telescope, just to see if the star I was observing was on the cross wires, and observers of doublestars also do visual observations, on the other hand, many amateurs use CCD-camara's nowadays
On the big scopes, the astronomers are not even allowed to touch the telescope. They tell the observatory technition(s) what they wish to observe and the tech moves the scope!

iwcarinae
2003-Jul-16, 12:09 PM
Do you really believe that? When I was a pro, I had to look through the telescope, just to see if the star I was observing was on the cross wires, and observers of doublestars also do visual observations, on the other hand, many amateurs use CCD-camara's nowadays
On the big scopes, the astronomers are not even allowed to touch the telescope. They tell the observatory technition(s) what they wish to observe and the tech moves the scope!
You are right about that one, big telescopes require expert handling, but the mt Palomar does have an oberving cabin at the prime focus, but looking through a telescope is not the same as doing observations with it, although seeing Saturnus with your own eyes, even through a small telescope, 20" , is still quite something.
I remember something happening a number of years ago, I think around 1970, I forgot all the details, but a bright star was occulted by one of the planets, and we had David Evans at the observatory, actually giving an eye witness report of the event, Eye glued to the eyepiece, he cried, "I see it, gone, I see it.."a.s.o. I had to write both the times and his cries, while parallel a photometer was recording the event. So, in spwecial occasions astronomers DO look through telescopes

sarongsong
2003-Jul-30, 11:57 AM
Smile, man on the moon!
http://oposite.stsci.edu/pubinfo/pr/1999/14/content/9914z.jpg
=D>

man on the moon
2003-Aug-01, 08:14 AM
me or the real one? :wink:

either way...:D

sarongsong
2003-Aug-01, 08:54 AM
Oh, that was for you---the 'impossible" HST portrait.