GetMasserPhase
GetSecundusPhase

They both return these values:

0 = MOON_PHASE_NEW (this is the default)
1 = MOON_PHASE_WAXING_CRESCENT or MOON_PHASE_WANING_CRESCENT:
2 = MOON_PHASE_WAXING_HALF or MOON_PHASE_WANING_HALF:
3 = MOON_PHASE_WAXING_GIBBOUS
or MOON_PHASE_WANING_GIBBOUS:
4 = MOON_PHASE_FULL