  We present a homogeneous and high signal-to-noise data set (mean S/N of ~60
per \AA) of Lick/IDS stellar population line indices and central velocity
dispersions for a sample of 132 bright (b_j < 18.0) galaxies within the central
1 deg (= 1.26 h^-1 Mpc) of the nearby rich Coma cluster (A1656). Our
observations include 73 per cent (100 out of 137) of the total early-type
galaxy population (b_j < 18.0). Observations were made with the WHT 4.2 metre
and the AUTOFIB2/WYFFOS multi-object spectroscopy instrument (resolution of 2.2
\AA FWHM) using 2.7'' diameter fibres (= 0.94 h^-1 kpc). The data in this paper
have well characterised errors, calculated in a rigorous and statistical way.
Data are compared to previous studies and are demonstrated to be of high
quality and well calibrated on to the Lick/IDS system. Our data have median
errors of ~0.1 \AA for atomic line indices, ~0.008 mag for molecular line
indices, and 0.015 dex for velocity dispersions. This work provides a
well-defined, high-quality baseline at z~0 for studies of medium to high
redshift clusters. Subsequent papers will use this data set to probe the
stellar populations (which act as fossil records of galaxy formation and
evolution) and the spectro-photometric relations of the bright early-type
galaxies within the core of the Coma cluster.
