  We present our final orbit for the late-type spectroscopic binary HD 1.
Employed are 553 spectra from 13 years of observations with our robotic STELLA
facility and its high-resolution echelle spectrograph SES. Its long-term
radial-velocity stability is $\approx$50m/s . A single radial velocity of HD 1
reached a rms residual of 63m/s, close to the expected precision. Spectral
lines of HD 1 are rotationally broadened with $v\sin i$ of 9.1$\pm$0.1 km/s .
The overall spectrum appears single-lined and yielded an orbit with an
eccentricity of 0.5056$\pm$0.0005 and a semi-amplitude of 4.44km/s . We
constrain and refine the orbital period based on the SES data alone to
2318.70$\pm$0.32d, compared to 2317.8$\pm$1.1d when including the older data
set published by DAO and Cambridge/Coravel. Owing to the higher precision of
the SES data, we base the orbit calculation only on the STELLA/SES velocities
in order not to degrade its solution. We redetermine astrophysical parameters
for HD 1 from spectrum synthesis and, together with the new {\it Gaia} DR-2
parallax, suggest a higher luminosity than published previously. We conclude
that HD 1 is a slightly metal-deficient K0 III-II giant 217 times more luminous
than the Sun. The secondary remains invisible at optical wavelengths. We
present evidence for the existence of a third component.
