Lunar Orbiter Reconnaissance Camera Resolving Power

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Rama Set

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Lunar Orbiter Reconnaissance Camera Resolving Power
« on: March 01, 2013, 05:43:13 AM »
Per the discussion in this thread regarding the capabilities of the LROC, I emailed an astronomer at Cornell University for an answer to why the LROC could not make out objects on the moon in greater detail. The answer is below:

Every camera and telescope -- and the LRO has a telescope-like set of lenses hooked to the camera, even if it's staring 'down' at the moon -- has a limit of how much detail it can pick up.  For cameras, it is a matter of pixel size.  For telescopes, it depends on a physical limit to focus the telescope (called the diffraction limit).  Normally things are matched so these are roughly the same -- it makes no sense to build a camera with more pixels than your optics can clearly use.

Think about zooming in on a digital picture in Photoshop (or your program of choice).  Eventually you get to a point where you are seeing individual pixels.  Even if you try to expand it more, you either get squares of color (the pixels) or a blur (the computer smoothing over the pixels). 

So, basically, LRO's cameras has a limit of the amount of detail it can make out.  It's a pretty tiny limit: LRO has two cameras, one of which can see down to 0.5 m per pixel and a bigger camera that only can see 100 m per pixel.  (A lot of missions will have two cameras or camera settings -- one camera to take pictures of the whole planet or moon, another to take detailed pictures of interesting things; if we tried to take a detailed picture of the whole moon, it would take a lot more camera time than we have.)

Now 0.5 m is very good for a planetary mission, but it's still 0.5 meters.  At that size, an astronaut laying down would take up around four pixels, and -- considering that LRO is looking 'mostly down' at things -- an astronaut standing up would be about a single pixel. The flag would take up a pixel, though it's shadow might be able to seen; looking down is a terrible angle for flags (but not that bad for flag shadows depending on the time of the day).  The lunar rovers would be larger, and top-down isn't as bad an angle for a rover, but even something the size of a car would look about like one of the letters in this email; you can make out what it is, but probably not any fine detail.

LRO could see more if we put it in a closer orbit, but its orbit was chosen to do so it can do both 'large scale' things like use its wide angle camera, and use instruments that need a closer range.  It also would be moving faster in a closer orbit, which could affect operations.  While more detail is always nice, eventually you get a tradeoff of ' this isn't worth the sacrifice of the other stuff we'd have to do to get this'.  (You hear this a lot in space missions.  There is a lot of compromise to get the most out of a mission for everyone involved; in this case, looking at pictures of moon rocks to learn things about large processes like craters and lava floods versus using instruments to tell us what the rocks are made of, versus methods to look for ice buried at the pole, versus better maps of the moon.)

I hope that cleared things up,

-- Rebecca Harbison
Aether is the  characteristic of action or inaction of charged  & noncharged particals.

Re: Lunar Orbiter Reconnaissance Camera Resolving Power
« Reply #1 on: March 01, 2013, 06:26:20 AM »
nice one Rama. very interesting read thanks for your effort. kinda goes with my statement that NASA does not wast money sending hugely expensive missions to the moon just to prove conspiracy nuts wrong. it has nothing to prove because it/they know they went. its not their fault a few you tube addicts don't believe in it. maby the conspiracay nuts should help finance a private mission with the sole purpous of photographing the landing sites. i bet they wont though

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sceptimatic

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Re: Lunar Orbiter Reconnaissance Camera Resolving Power
« Reply #2 on: March 01, 2013, 07:04:25 AM »
nice one Rama. very interesting read thanks for your effort. kinda goes with my statement that NASA does not wast money sending hugely expensive missions to the moon just to prove conspiracy nuts wrong. it has nothing to prove because it/they know they went. its not their fault a few you tube addicts don't believe in it. maby the conspiracay nuts should help finance a private mission with the sole purpous of photographing the landing sites. i bet they wont though
N.A.S.A doesn't waste money.

Bugatti veyron , cost 2 million (approx)

Moon buggy, cost $38 million.

N.A.S.A doesn't waste money.

Re: Lunar Orbiter Reconnaissance Camera Resolving Power
« Reply #3 on: March 01, 2013, 07:04:35 AM »
nice one Rama. very interesting read thanks for your effort. kinda goes with my statement that NASA does not wast money sending hugely expensive missions to the moon just to prove conspiracy nuts wrong. it has nothing to prove because it/they know they went. its not their fault a few you tube addicts don't believe in it. maby the conspiracay nuts should help finance a private mission with the sole purpous of photographing the landing sites. i bet they wont though

Would be fun to see that project on Kickstarter
I'd like to agree with you but then we'd both be wrong!

Re: Lunar Orbiter Reconnaissance Camera Resolving Power
« Reply #4 on: March 01, 2013, 07:08:15 AM »
nice one Rama. very interesting read thanks for your effort. kinda goes with my statement that NASA does not wast money sending hugely expensive missions to the moon just to prove conspiracy nuts wrong. it has nothing to prove because it/they know they went. its not their fault a few you tube addicts don't believe in it. maby the conspiracay nuts should help finance a private mission with the sole purpous of photographing the landing sites. i bet they wont though
N.A.S.A doesn't waste money.

Bugatti veyron , cost 2 million (approx)

Moon buggy, cost $38 million.

N.A.S.A doesn't waste money.

i said NASA does not waste money pandering the the cowardly whims of conspiracy nuts. i didn't say they don't waste money at all. i believe NASA can be very wastfull and that's why i am far more optimistic about private space flight and companies than any government controlled one. private enterprise beats government investment hands down every time.

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Rama Set

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  • I am also an engineer
Re: Lunar Orbiter Reconnaissance Camera Resolving Power
« Reply #5 on: March 01, 2013, 07:10:01 AM »
nice one Rama. very interesting read thanks for your effort. kinda goes with my statement that NASA does not wast money sending hugely expensive missions to the moon just to prove conspiracy nuts wrong. it has nothing to prove because it/they know they went. its not their fault a few you tube addicts don't believe in it. maby the conspiracay nuts should help finance a private mission with the sole purpous of photographing the landing sites. i bet they wont though
N.A.S.A doesn't waste money.

Bugatti veyron , cost 2 million (approx)

Moon buggy, cost $38 million.

N.A.S.A doesn't waste money.

I just wanted a good explanation of why you can't make out the flag or detail on the lunar rover on the moon.  You have it now, so best find something else to apply your thoughts to.
Aether is the  characteristic of action or inaction of charged  & noncharged particals.