NSEA · Elementary Astronomy

Telescopes and Instruments

Refracting/reflecting telescopes, magnification, resolving power and modern observatories.

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  • Q1 · Telescopes and Instruments · MEDIUM

    A Newtonian reflector telescope has a primary mirror of diameter 20 cm and focal length 100 cm. What is its f-number (focal ratio)?

  • Q2 · Telescopes and Instruments · MEDIUM

    A refracting telescope has an objective lens of focal length 120 cm and an eyepiece of focal length 2.5 cm. What is the magnifying power of this telescope in normal adjustment?

  • Q3 · Telescopes and Instruments · EASY

    A telescope has a primary mirror diameter of 2.4 meters and operates at a wavelength of 600 nm. What is the approximate angular resolution (in arcseconds) of this telescope according to the Rayleigh criterion?

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