pub fn beta_angle(
orbit_normal: [f64; 3],
sun: [f64; 3],
) -> Result<f64, AngleError>Expand description
Solar beta angle (degrees, signed, in [-90, 90]): the elevation of the Sun
above the orbit plane, beta = 90 - angle(orbit_normal, sun), computed in
the normative pi/2 - acos(clamp(cos)) operation order.
orbit_normal is the orbit-plane normal, for example r x v; sun is the
Earth-to-Sun vector. Both must be in the same inertial frame. Only their
directions matter. Sign is positive when the Sun is on the +orbit_normal
side of the plane.