Longitude of Ascendant and House Cusp Calculation:
The ascendant is the same for most house systems, as is the MC (which is not the tenth house cusp in equal house systems). Regiomontanus has the same ASC and MC as Placidus, Campanus, Koch etc. R = arctan (sin (H) * tan (glat) / cos (RAMC + H)) correct quadrant to be use Longitude of cusp = arctan ((cos (R) * tan (RAMC + H)/ cos (R + E)) correct quadrant to be use Blow function will provide correct degree in all Quadrant R = DegAtan2(DegSin(H) * DegTan(glat), DegCos(RAMC + H)) LCusp = DegAtan2(DegCos(R) * DegTan(RAMC + H), DegCos(R + E)) For cusps: 1. 10 (MC): H = 0 2. 11: H = 30 3. 12: H = 60 4. 1 : H = 90 5. 2 : H = 120 6. 3 : H = 150 7. 4 : H = 180 8. 5 : H = 210 9. ...