Re: ATM super scopes

["Benoit Schillings" <benoit@be.com>]

>
>
>   I occasionally see on the newscast articles concerning spy 
>satelites/planes with their extraordinary ability to see detail such 
as a 
>licence plate from space. Are there really such optics and if so is 
this 
>something an amature could shoot for? 
>
>                        (  Adams@rmci.net )    
>
>


This is a pretty interesting question, even if off topic...

Let's see...

It is known that there are some 4 meters scope in orbit (or at least
suspected)...

a 4 meters scope will give a FWHM of 0.05 arc/sec at 600 nm (more or 
less)...

If I remember, those scope generally work in the near IR, so let's say
0.07 arc/sec FWHM.

I suppose that there must be some sort of adaptive optics to cut the 
seeing
looking down, otherwise such large scope would be pointless...

Basic deconvolution algorithm can give at least a 2x increase in 
resolution
if the signal to noise is good enough... so 0.035 arc/sec fwhm...

>From 200 miles up, this comes down to about 2 inches... not good enough 
for
licence plate, but still... pretty good.


                -- Benoit