An astronaut in orbit can just resolve two point sources on the earth that are 7

Question

An astronaut in orbit can just resolve two point sources on the earth that are 70.0 m apart. Assume that the resolution is diffraction-limited and use Rayleigh's criterion. What is the astronaut's altitude above the earth? Treat her eye as a circular aperture with a diameter of 4.00 mm (the diameter of her pupil), and take the wavelength of the light to be 510 nm.

What I tried:
tan() = 70m/h
h = 70m/tan() where is the minimum angle in the equation D = 1.22/

==> = 1.22/D

so,

h = 70m/tan(1.22*510E-9/(4E-3)) = 2.58E8 m.

It's wrong, help!

Explanation / Answer

wavelength = 510 nm = 510 * 10 ^-9 m diameter d = 4 mm = 4* 10 ^-3 m separation between two point sources y = 70 m Let the altitude of the astronaut be D we know from Rayleigh's criterion y = 1.22 D / d from this   D = yd / [1.22 ] plug the values we get D = 450.016*10^3 m Note : ------ In some books   y = D / d from this D = yd /                    = 549.019*10^ 3 m

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