We develop a dynamical model of the dwarf nova binary AH Herculis based upon high-resolution phase-resolved spectroscopy from the 2.5-m Hooker reflector at Mt Wilson. The distorted double-peaked Balmer emission lines from the accretion disc surrounding the white dwarf primary star have a peak-to-peak separation of 600 km s−1. From radial velocity variations of the emission lines over a one-year baseline we determine the binary period P=0.258116±0.000004 day. We detect the weak absorption spectrum of the cool mass-losing companion star AH Her B, and use a cross-correlation method to measure its orbit radial velocity curve. The spectral type of AH Her B is early-to-middle K, but the Mg b lines are much weaker than expected relative to Fe I. The radial velocity semi-amplitudes |Kₑms=126±4 km s⁻¹| for the emission line wings and |Kₐbs=158±8 km s⁻¹| for the absorption lines imply mass functions |MWsin³ i=0.34±0.04 M_, MRsin³ i=0.27±0.03 M_, and asin i=14.5±0.05 R_|. If we impose an empirical ZAMS mass-radius relationship on the companion star, then |i=46^∘±3^∘, MW=0.95±0.10 M_ and MR=0.76±0.08 M_|.
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Horne et al. (1986) studied this question.