  We measure the temperature of ultra-cold Rb-87 gases transferred into an
optical lattice and compare to non-interacting thermodynamics for a combined
lattice--parabolic potential. Absolute temperature is determined at low
temperature by fitting quasimomentum distributions obtained using bandmapping,
i.e., turning off the lattice potential slowly compared with the bandgap. We
show that distributions obtained at high temperature employing this technique
are not quasimomentum distributions through numerical simulations. To overcome
this limitation, we extract temperature using the in-trap size of the gas.
