# Can we see the USA flag on the moon? **URL:** \ **Category:** Factual Questions\ **Created:** [December 2, 2002, 7:53pm UTC](https://boards.straightdope.com/t/can-we-see-the-usa-flag-on-the-moon/140022 "2002-12-02T19:53:31Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Padeye](https://avatars.discourse-cdn.com/v4/letter/p/a9a28c/32.png) [@Padeye](https://boards.straightdope.com/u/Padeye)\ **Post date:** [December 3, 2002, 5:31pm UTC](https://boards.straightdope.com/t/can-we-see-the-usa-flag-on-the-moon/140022/21 "2002-12-03T17:31:20Z")
> [@](#): > > \*Originally posted by Bryan Ekers \* > \*\*You _can_ snap good-quality photographs of large lunar features like craters and whatnot and get minimal blurring, but when your targets get smaller and smaller, you’ll need faster exposures which means you’ll capture less light. Since the lunar _Apollo_ objects aren’t generating light as the stars do (or reflecting sunlight to a large degree, as the moon’s albedo does) seeing them in any detail is going to pose a serious technical challenge. I’d be very impressed if the VLT can pick up more than a few vague dark spots representing the landers themselves. I’d be downright amazed if they could spot the flags in recognizable detail. In any event, I don’t expect it to rattle any devout hoax-believers. \*\* Moon photos don’t require long exposures. It’s illuminated by direct sunlight so the same f16 exposure rule used on earth works for moon photos. Still, the ultimate resolution will be limited by the physical size of the optics. Even the most massive telescopes on earth will only be able to render the landing sites as a spec. ---
**Author:** ![JackL](https://avatars.discourse-cdn.com/v4/letter/j/ac91a4/32.png) [@JackL](https://boards.straightdope.com/u/JackL)\ **Post date:** [December 3, 2002, 5:39pm UTC](https://boards.straightdope.com/t/can-we-see-the-usa-flag-on-the-moon/140022/22 "2002-12-03T17:39:00Z")
With 130 meter resolution, I wonder though if the VLT could someday image the long shadow cast by the Apollo lander when the Sun is low on the horizon. It just amazes me that the VLT telescope can take such an incredible image of the moon thru the Earth’s atmosphere! [http://spaceflightnow.com/news/n0208/12taruntius/](http://spaceflightnow.com/news/n0208/12taruntius/) Anyways, “Bryan” you are wrong about the VLT’s capabilties! ---
**Author:** ![Drum\_God](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/drum_god/32/44_2.png) [@Drum\_God](https://boards.straightdope.com/u/Drum_God)\ **Post date:** [December 3, 2002, 6:31pm UTC](https://boards.straightdope.com/t/can-we-see-the-usa-flag-on-the-moon/140022/23 "2002-12-03T18:31:07Z")
On a related topic, in the movie _Star Trek: First Contact_, Picard and Co. are mucking about 21st century Montana. One of the characters looks at the partially lit moon in the night sky and remarks how strange that the dark side of the moon is so black and not lit by the many cities there in the 24th century. Sooooo, if the moon is too far away to see artifacts, could a person see the lights of cities from the earth (if cities were there, of course)? ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [December 3, 2002, 6:55pm UTC](https://boards.straightdope.com/t/can-we-see-the-usa-flag-on-the-moon/140022/24 "2002-12-03T18:55:14Z")
So, I’m “wrong”, am I? So, I’m “Bryan”, am I? 130 meters is pretty good but the lander is considerably smaller and it’s not generating its own light, or having spotlights shining directly on it to illuminate it. It is, at best, a little brighter from reflected sunlight than the surrounding regolith because of the metal used in its construction. If anyone gets a picture of it, it’ll be a greyish dot. Under optimal conditions, you might get a picture of a long shadow, but how would you distinguish it from all the long shadows from the various boulders, ridges and other natural features? Feel free to go ahead and build the Ultra Large Telescope or the Super Large Telescope with a resolution better than 130 meters. I hope you have a few billion bucks handy in your checking account. If you wanted to put something on the Moon that could be seen from Earth, the astronauts could have spread out a half-acre of super-shiny ultra-thin mylar or something. Too bad they didn’t take any with them. They could have spelled out USA or something. If you want recognizable images of the landers, I still think your best bet would be to put a satellite in orbit around the moon. If you choose an eccentric elliptical orbit, the satellite could pass just a few hundred meters above the surface and could easily snap photos of the flags. Plan it right, and you could get photos of more than one landing site. ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [December 3, 2002, 7:06pm UTC](https://boards.straightdope.com/t/can-we-see-the-usa-flag-on-the-moon/140022/25 "2002-12-03T19:06:20Z")
> [@](#): > > \*Originally posted by Drum God \* > \*\*On a related topic, in the movie _Star Trek: First Contact_, Picard and Co. are mucking about 21st century Montana. One of the characters looks at the partially lit moon in the night sky and remarks how strange that the dark side of the moon is so black and not lit by the many cities there in the 24th century. Well, actually, there is no “dark side of the moon”. All the lunar surface is lit at some point during its orbit. There is a side of the moon that is always facing away from Earth, but that doesn’t make it “dark”. I could sort-of imagine a ring of cities around the moon’s equator, but they’d have a two-week cycle of sunlight and dark so you’d have to be some kind of troll to live there. ---
**Author:** ![Nametag](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nametag/32/406_2.png) [@Nametag](https://boards.straightdope.com/u/Nametag)\ **Post date:** [December 3, 2002, 7:15pm UTC](https://boards.straightdope.com/t/can-we-see-the-usa-flag-on-the-moon/140022/26 "2002-12-03T19:15:23Z")
Uh, if they’re in Montana, they’re looking at the near side of the moon, and “dark side” refers to the part of the near side that’s dark **at that time**. Apparently, this dark part is visibly lit by artificial lights in the 24th century. ---
**Author:** ![Patty\_O\_Furniture](https://avatars.discourse-cdn.com/v4/letter/p/96bed5/32.png) [@Patty\_O\_Furniture](https://boards.straightdope.com/u/Patty_O_Furniture)\ **Post date:** [December 3, 2002, 7:39pm UTC](https://boards.straightdope.com/t/can-we-see-the-usa-flag-on-the-moon/140022/27 "2002-12-03T19:39:48Z")
In [this thread on the JREF Boards](http://host.randi.org/vbulletin/showthread.php?postid=203492#post203492), a poster named **karl** seems to have his act together with regard to calculating the necessary aperture size on a telescope in order to obtain a given resolution at a certain distance. He also offers the formula in case anybody’s interested. I’ve linked directly to the post in question. Earlier on page 2, I have posted satellite images showing 4, 2 and 1 meter resolution of the White house\*. Don’t bother with the first page of that thread, it’s unrelated to the more interesting hijack on optics. \*[sub]Just for reference. I’m not planning anything, really![/sub] ---
**Author:** ![Patty\_O\_Furniture](https://avatars.discourse-cdn.com/v4/letter/p/96bed5/32.png) [@Patty\_O\_Furniture](https://boards.straightdope.com/u/Patty_O_Furniture)\ **Post date:** [December 3, 2002, 7:48pm UTC](https://boards.straightdope.com/t/can-we-see-the-usa-flag-on-the-moon/140022/28 "2002-12-03T19:48:06Z")
By the way, that 130 meter res. picture of the moon is nice and all, but to pick out enough detail to confirm the presence of a lunar lander, even 1 meter resolution probably wouldn’t be good enough. We’d get a few dark pixels that indicate, sure enough, _something_ is down there (up there?). To confirm that the object is a lunar lander we’d probably need something like decimeter resolution. ---
**Author:** ![Patty\_O\_Furniture](https://avatars.discourse-cdn.com/v4/letter/p/96bed5/32.png) [@Patty\_O\_Furniture](https://boards.straightdope.com/u/Patty_O_Furniture)\ **Post date:** [December 3, 2002, 7:50pm UTC](https://boards.straightdope.com/t/can-we-see-the-usa-flag-on-the-moon/140022/29 "2002-12-03T19:50:33Z")
Okay, this thread is about seeing the flag, not the lunar lander. So we’d probably need centimeter resolution for that. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [December 3, 2002, 8:00pm UTC](https://boards.straightdope.com/t/can-we-see-the-usa-flag-on-the-moon/140022/30 "2002-12-03T20:00:21Z")
The brightness of the Moon is one of the reasons why they delayed so long shooting it with the Hubble. Standard operation for the Hubble calls for keeping the Moon at least 30 degrees out of the field of view at all times (the Sun is kept 45 degrees away). Being in space, glare isn’t an issue, but they wanted a safety factor in case the tracking malfunctioned and the scope drifted. Presumably, they figured out how to resolve this by the time they took the Moon pictures, but you’ll also note that they didn’t try it until after the primary science objective (measurement of SN1as at cosmological distances) was completed. Cities on the Moon probably would show up, assuming that they spilled as much light pollution as terrestrial cities (which they probably wouldn’t, but that’s another issue). A pinprick of light can be seen even if it’s below the resolution limit; you just won’t see any detail in it. And a city and surrounding metropolitan area would easily be hundreds of miles across, within even the naked-eye resolution limit. ---
**Author:** ![Sofa\_King](https://avatars.discourse-cdn.com/v4/letter/s/58956e/32.png) [@Sofa\_King](https://boards.straightdope.com/u/Sofa_King)\ **Post date:** [December 3, 2002, 8:05pm UTC](https://boards.straightdope.com/t/can-we-see-the-usa-flag-on-the-moon/140022/31 "2002-12-03T20:05:53Z")
If one were to look at the later sites, Apollos 15-17, there is a good chance that the tracks left by the [LRV](http://www.astronautix.com/craft/apololrv.htm)s would give the whole site a better chance of being seen. I still don’t think it would show up as much under 160-meter resolution–just a few pixels, I would imagine. I remember a particular film clip recorded on one of those missions (I think it was 17), looking down from the ascent stage as it launched from the surface of the moon. For a few seconds there is a view of the entire site, which could probably be matched against any modern photos taken. Regrettably, I couldn’t find the film available on the Internet. However, you can see it in the excellent National Geographic film, _For All Mankind_. Of course, it’s not definitive proof to those who wish to deny Apollo happened–some chowderhead will just argue that the LRV was remote controlled. If you spot footprints, they’ll argue it’s a robot wearing boots. What can you do? When someone lives in a vacuum, it’s pointless to tell him to go pee in a fan. ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [December 3, 2002, 8:19pm UTC](https://boards.straightdope.com/t/can-we-see-the-usa-flag-on-the-moon/140022/32 "2002-12-03T20:19:16Z")
> [@](#): > > \*Originally posted by Sofa King \* > When someone lives in a vacuum, it’s pointless to tell him to go pee in a fan. \*\* Not to engage in completely ridiculous petty hairsplitting pointless nitpicking, but why would you have a fan running in a vacuum? Not that there’s anything wrong with that. ---
**Author:** ![bernse](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@bernse](https://boards.straightdope.com/u/bernse)\ **Post date:** [December 3, 2002, 8:21pm UTC](https://boards.straightdope.com/t/can-we-see-the-usa-flag-on-the-moon/140022/33 "2002-12-03T20:21:09Z")
As a slight hijack, Was the Mars Surveyor able to pick up photographs (pixel size?) of craft on the Mars surface be it Vikings or Pathfinder? ---
**Author:** ![KneadToKnow](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kneadtoknow/32/3999_2.png) [@KneadToKnow](https://boards.straightdope.com/u/KneadToKnow)\ **Post date:** [December 3, 2002, 8:24pm UTC](https://boards.straightdope.com/t/can-we-see-the-usa-flag-on-the-moon/140022/34 "2002-12-03T20:24:23Z")
I’ve been reading this thread with interest and I’m curious about something. If we can’t see from earth something on the moon as big as a lunar lander, then how do they manage to make satellites that can see something on earth as small as the text on a license plate? (Granted I’m taking the widely-held belief that spy satellites can read a licens plate at face value, but you see the point I’m making, I hope.) Is the difference entirely accounted for in the fact that the satellites are much closer to the object than we are to the moon? Or is there something else at work? ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [December 3, 2002, 8:29pm UTC](https://boards.straightdope.com/t/can-we-see-the-usa-flag-on-the-moon/140022/35 "2002-12-03T20:29:22Z")
> [@](#): > > \*Originally posted by KneadToKnow \* > If we can’t see from earth something on the moon as big as a lunar lander, then how do they manage to make satellites that can see something on earth as small as the text on a license plate? (Granted I’m taking the widely-held belief that spy satellites can read a licens plate at face value, but you see the point I’m making, I hope.) > > Is the difference entirely accounted for in the fact that the satellites are much closer to the object than we are to the moon? Or is there something else at work? Well, distance between Earth-based telecope and Moon: 250,000 miles. Distance between low-orbiting spy satellite and Osama’s license plate: maybe 250 miles. I think the 1000-to-1 factor is kind of a major hurdle. ---
**Author:** ![Sofa\_King](https://avatars.discourse-cdn.com/v4/letter/s/58956e/32.png) [@Sofa\_King](https://boards.straightdope.com/u/Sofa_King)\ **Post date:** [December 3, 2002, 8:37pm UTC](https://boards.straightdope.com/t/can-we-see-the-usa-flag-on-the-moon/140022/36 "2002-12-03T20:37:28Z")
Aha! That’s exactly what we need, then. Just put a [KH-11](http://www.astronautix.com/craft/kh11.htm) in orbit around the moon, and there you have your shot of the flag. ---
**Author:** ![KneadToKnow](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kneadtoknow/32/3999_2.png) [@KneadToKnow](https://boards.straightdope.com/u/KneadToKnow)\ **Post date:** [December 3, 2002, 8:38pm UTC](https://boards.straightdope.com/t/can-we-see-the-usa-flag-on-the-moon/140022/37 "2002-12-03T20:38:15Z")
Fair enough, as I said, I was just wondering if anything else (like geosynchronicity) played a role. Thanks! ---
**Author:** ![BioHazard](https://avatars.discourse-cdn.com/v4/letter/b/3bc359/32.png) [@BioHazard](https://boards.straightdope.com/u/BioHazard)\ **Post date:** [December 3, 2002, 8:54pm UTC](https://boards.straightdope.com/t/can-we-see-the-usa-flag-on-the-moon/140022/38 "2002-12-03T20:54:21Z")
IANAP and IANA Photographer so im winging this. Why can’t the VLT take hundreds of photos each one 1/100 of a pixel offset then use a computer to combine them all? Wouldn’t that make the resolution 1.5 meters? Cant you extend this to centimeter resolution? ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [December 3, 2002, 8:54pm UTC](https://boards.straightdope.com/t/can-we-see-the-usa-flag-on-the-moon/140022/39 "2002-12-03T20:54:36Z")
> [@](#): > > \*Originally posted by Sofa King \* > \*\*Aha! That’s exactly what we need, then. Just put a [KH-11](http://www.astronautix.com/craft/kh11.htm) in orbit around the moon, and there you have your shot of the flag. \*\* Plus we’ll be able to detect any Iraqi movement, since the President is claiming that Saddam’s next target is the moon itself. Thus, Congress should immediately back a pre-emptive strike. It’s in _Revelations_, people! ---
**Author:** ![Sofa\_King](https://avatars.discourse-cdn.com/v4/letter/s/58956e/32.png) [@Sofa\_King](https://boards.straightdope.com/u/Sofa_King)\ **Post date:** [December 3, 2002, 9:39pm UTC](https://boards.straightdope.com/t/can-we-see-the-usa-flag-on-the-moon/140022/40 "2002-12-03T21:39:06Z")
Come to think of it, since the moon has no atmosphere, couldn’t you just orbit a very high-rez television camera in a polar orbit at 10,000 feet, or whatever it takes to reliably clear the tallest point on the moon? Sooner or later you’d go right overtop of all of the landing sites. [Previous page](https://boards.straightdope.com/t/can-we-see-the-usa-flag-on-the-moon/140022.md?page=1) [Next page](https://boards.straightdope.com/t/can-we-see-the-usa-flag-on-the-moon/140022.md?page=3)