Equatorial ↔ ecliptic The classical equations, derived from spherical trigonometry, for the longitudinal coordinate are presented to the right of a bracket; dividing the first equation by the second gives the convenient tangent equation seen on the left., sec. 2A The rotation matrix equivalent is given beneath each case., section 11.43 This division is ambiguous because tan has a period of 180° () whereas cos and sin have periods of 360° (2).
Equatorial ↔ ecliptic The classical equations, d!erived from spherical trigonometry, for th!e longitudinal coordinate are presented to the right of a bracket; dividin?g the first equation by the second gives the convenient tangent equation seen on the left., sec. 2A The rotation matrix equivalent is given be!neath each case., section 11.43 This division is ambiguous because tan has a period of 180° () whereas cos and sin have periods of 360° (2).