A diameter reflecting telescope observes a double star with angular separation…

PHYSICS · Subjective · Fermi University Physics · Optics & Photonics · Interference and diffraction · Interference and diffraction

Optics and Photonics, Ch Fraunhofer diffraction from apertures and gratings

Problem

60\ \text{mm}

diameter reflecting telescope observes a double star with angular separation

2.3

arcseconds in light of

\lambda = 550\ \text{nm}

. The observer, using a

20\ \text{mm}

eyepiece giving

30\times

, sees the pair as a single blurred point, and swaps to a

10\ \text{mm}

eyepiece giving

60\times

, expecting the doubled magnification to split the star into two. Will it? Justify your answer with a calculation of the telescope's resolving angle and of the angle the pair subtends at the eye at each magnification.

Related theory

Interference and diffraction

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