The two Keck 10-meter telescopes,separated by a distance of 85 meters,can operate as an interferometer.What is its resolution when it observes in the infrared at a wavelength of 2 μm?
A) 0.01 arcsec
B) 0.005 arcsec
C) 0.05 arcsec
D) 0.2 arcsec

Question

Quizplus · Accepted Answer

The resolution of an interferometer is given by the formula: 
resolution = 1.22 x wavelength / baseline 
where wavelength is in meters and baseline is the distance between the two telescopes in meters. 
Converting the wavelength of 2 μm to meters, we get: 
wavelength = 2 x 10^-6 m 
Substituting this along with the baseline of 85 meters into the formula, we get: 
resolution = 1.22 x (2 x 10^-6) / 85 
resolution ≈ 0.0000288 radians 
Converting this to arcseconds, we get: 
resolution ≈ 0.005 arcsec 
Therefore, the best choice is B.

The Two Keck 10-Meter Telescopes,separated by a Distance of 85