We present a detailed spectroscopic study of Herschel 36 A ( H36A ) , the main stellar component of the massive multiple system Herschel 36 in the Hourglass Nebula , based on high-resolution optical spectra obtained along an 11 years span . The three stellar components present in the spectrum of H36A are separated by means of a spectral disentangling technique . Individual spectral classifications are improved , and high precision orbital solutions for the inner and the outer orbits are calculated . H36A is confirmed to be a hierarchical triple system composed of a close massive binary ( Ab1+Ab2 , O9.5 V+B0.7 V ) in wide orbit around a third O-type star ( Aa , O7.5 Vz ) . The inner-pair orbit is characterized by a period of 1.54157 \pm 0.00006 days , and semi-amplitudes of 181.2 \pm 0.7 and 295.4 \pm 1.7 km s ^ { -1 } . The outer orbit has a period of 492.81 \pm 0.69 days , and semi-amplitudes of 62.0 \pm 0.6 and 42.4 \pm 0.8 km s ^ { -1 } . Inner and outer orbits are not coplanar , having a relative inclination of at least 20 degrees . Dynamical minimum masses of 20.6 \pm 0.8 M _ { \sun } , 18.7 \pm 1.1 M _ { \sun } , and 11.5 \pm 1.1 M _ { \sun } are derived for the Aa , Ab1 , and Ab2 components , respectively , in reasonable agreement with the theoretical calibrations .