Exercise2:

The coordinates of the Galactic North Pole are given officially as
α = 12h49m00s, δ = +27°24'00",
relative to the equator and equinox of 1950.0.

What should they be,
relative to the equator and equinox of 2000.0?

(For this calculation, take the values of m and n for the year 1975:
m = 3.074s per year;
n = 1.337s per year = 20.049" per year.)

The formulae are:
     Δα = m + n sin(α) tan(δ)
     Δδ = n cos(α)

Substitute the coordinates given in the question:
     α₁₉₅₀ = 12h49m00s = 192.25°,
     δ₁₉₅₀ = +27°24'00" = 27.40°,
to get
     Δα = 2.927s per year, or +146.348s in 50 years.
     Δδ = -19.59" per year, or -979.63" in 50 years.

Add these to the 1950 values of α and δ, to get
     α₂₀₀₀ = 12h51m26s
     δ₂₀₀₀ = +27°07'40"

Back to "precession".