capabilities of satellite

[Ivan Tuzikov]

Hello everybody.

 

1. Object of what minimum size can we detect in space using optical telescopes and radiolocation? (and at what distance?)

2. What resolution shall have a telescope (on a satellite) to be able to clearly discern a face of a human on earth? How far in deep space from Earth can such satellite with telescope be placed to maintain it's ability to discern human faces on earth?

Let's imagine that it moves simultaneously with the Earth's rotations.

 

Thanks in advance.

[Klaynos]

Have a look at the rayleigh criterion. You'll see it depends on the size of the aperture (mirror in most telescopes) and the distance.

[Ivan Tuzikov]

Have a look at the rayleigh criterion. You'll see it depends on the size of the aperture (mirror in most telescopes) and the distance.

 

Say, Hubble telescope has D:2400 mm of main mirror and magnification respectively 4800 (if I understand correctly it is 2xD in mm).

angular resolution is 0.1 s

 

I read this (Rayleigh), but can't understand how to correctly calculate the aforementioned conditions which I presented.

I became involved with correct units of measurement.

For example:

The angular resolution may be converted into a spatial resolution, Δl, by multiplication of the angle (in radians) with the distance (unit?) to the object. For a microscope, that distance is close to the focal length f (unit?) of the objective. For this case, the Rayleigh criterion reads:

 

.Maybe someone could find formulae where correlation between distance from telescope to object, magnification and spatial resolution can be easily seen...

[Klaynos]

Sorry, posting on my phone, units are si, so, radians, and meters.