NSEA · Elementary Astronomy

Spherical Trigonometry

Sine and cosine rules on a sphere — used for converting between coordinate systems.

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  • Q1 · Spherical Trigonometry · HARD

    Two stars have right ascensions α₁ = 2h and α₂ = 8h, and both have declination δ = +30°. What is the angular separation between them on the celestial sphere?

  • Q2 · Spherical Trigonometry · HARD

    Two stars A and B have celestial coordinates (α₁ = 3h 20m, δ₁ = +40°) and (α₂ = 5h 40m, δ₂ = +30°) respectively. What is the approximate angular separation between them?

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