  We present new calculations of Rosseland and Planck gaseous mean opacities
relevant to the atmospheres of giant planets and ultracool dwarfs. Such
calculations are used in modeling the atmospheres, interiors, formation, and
evolution of these objects. Our calculations are an expansion of those
presented in Freedman et al. (2008) to include lower pressures, finer
temperature resolution, and also the higher metallicities most relevant for
giant planet atmospheres. Calculations span 1 microbar to 300 bar, and 75 K to
4000 K, in a nearly square grid. Opacities at metallicities from solar to 50
times solar abundances are calculated. We also provide an analytic fit to the
Rosseland mean opacities over the grid in pressure, temperature, and
metallicity. In addition to computing mean opacities at these local
temperatures, we also calculate them with weighting functions up to 7000 K, to
simulate the mean opacities for incident stellar intensities, rather than
locally thermally emitted intensities. The chemical equilibrium calculations
account for the settling of condensates in a gravitational field and are
applicable to cloud-free giant planet and ultracool dwarf atmospheres, but not
circumstellar disks. We provide our extensive opacity tables for public use.
