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does anyone know what the best 'spy' satelites can image on the ground? I was in an argument with some freinds on the probabilty of the view angles and resolution from photographing the earth from a spy satellite.

they said the spy sats can read the date on a quarter on the ground from 400 miles up. I dont buy it for a second. I can barely believe liscense plates on cars.
the resolution arcsecond angle just does not seem possible with the astronomical photography currently in use.

Without trying to sound too much like a paranoid stoner, if I can see my house with google earth i'd bet the man has something far better.

that sounds totally like something a stoner would say....

they're out to get us man, it's the iluminati...

I don't know, but I wouldn't doubt it. How do you know what technology the military currently uses?

Hubble can see light years away... So 400 miles for a US spy sat, that must of been 10 years ago or more that they got that kind of technology in use!

It's the atmosphere that's the problem. Hubble can see far through vacuum and it's looking at really big things.

Most of the urban photographs on Google Earth are taken from aircraft to get better detail.

Supposedly spy satellites can see some good detail, but I'm guessing it has to be pretty dependant on atmospheric conditions. In LA, you can barely see the building down the block, let alone a quarter.

looking across horizontally at the smog in LA is not the same as looking down, they can see your car tag that was long time ago, now the new satellite maybe able to see quarter

looking horizontaly and verticaly are different, but horizontal viewing problems are different from verticle viewing problems.

the optical lensing effects of light going through a few hundred miles of atmosphere are impressive.

its an arcsecond view angle problem for me.

I THINK:
that COMPLETELY ignoring the atmoshperic lensing noise AND ignoring the gravitational lensing effects, it is STILL (i think) impossible to view a date on a quarter from 400 miles. hell, i bet its impossible to distinguish a quarter from a silver rock.

Indeed -- being able to resolve objects the size of a quarter is completely different from making out details on the quarter.

Generally these 'size of a quarter' statements seem to come from somone taking a technical number and then poking around for a real-world object of about the right size to serve as a good example.

Have you tried web resources such as Google or Wikipedia? They might not be completely accurate, but the information will probably be better than you'll get by asking random internet users. Unless of course someone *actually knows*, in which they probably can't tell you.

 Unless of course someone *actually knows*, in which they probably can't tell you.
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he can but than he got to go and kill every one the log's on here

we have spy satellite for a long time now, they take photo of enemy movement and missile site all the time they shroud have figure out the most of the problem by now don't you think?

I understand there are MANY different imaging electromagnetic frequencies, everything from visible light to Xray.

but shit, you kids do the math.

Date on a quarter, 1mm numerals. minimum low orbit sat distance=170km. that angle is irresponsible.

(PS-im only talking about freefall orbit sats, NOT spy aircraft)

how many pixels height do you need to read a number? even given best case orientation, about 5? so... we are talking .2mm per pixel, at 170km.

 
For sure. They could probably read the size number off your pilot chute cap as you exit, no? A good movie on this topic is Enemy of the State.

oh for sure, all that stuff is totaly believeable.

PS-im only talking about freefall orbit sats, NOT spy aircraft
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spy satellite's main purpose is to take reconnaissances photo's, spy aircraft can be shot down with missile easily now days

if in seventies they mak this man, wat is it they can do now?

Math is on your side.

They use UAVs for reasons other than atmospheric conditions.

Distinguishing a quarter is impossible for a spy satellite. The image is "diffraction limited." Not only that, there's too much atmospheric turbulence and other disturbances such as clouds, smog, and high humidity.

New radar technologies are potentially allowing 2 cm image resolution at 1000 km but that requires huge equipment (a 36 m parabolic dish for example) that must be land based.

my thoughts exactly.

thanks guys. now i can go tell my stupid over-paranoid stoner freinds that they are ignorant and stupid.

Space Imaging (aka GeoEye) can take images at 15 cm (5.905 in.) resolution. This is the highest resolution sat photos that I am aware of.

"According to an estimate by the private Federation of American Scientists (FAS), three satellites operated by the US National Reconnaissance Office (NRO) have resolutions as sharp as 10 centimeters (3.93 inches) -- in other words, the satellites can discern a softball-sized object from several hundred miles away."

Still not impressed. not terribly better than what is available on google earth.

google earth they are not up to date some of the pic in 1mo. 2m. or 1year old, this one B I jump that I look up little while ago on google earth it only show a dirt field

2.43E-4 arcsec resolution (0.000243)

that is the resolution angle for a LEO sat at 170km (SUPER low earth orbit, extreme atmo drag and degrading orbit) viewing at 1pxl per .2mm(required to view the date on a US quarter dollar[5pxls height to distinguish date numeral])

not a chance.

Ye but who buys WMD's with a truck load of quarters any way?

just want to know the technology.