  We present a simulation of the spatial, luminosity and spectral distributions
of four types of stellar objects. We simulate: (1) Galactic stars, based on a
Galactic structure model, a stellar population synthesis model, stellar
isochrones, and stellar spectral libraries; (2) white dwarfs, based on model
atmospheres, the observed luminosity function, mass distribution, and Galactic
distribution of white dwarfs; (3) quasars, based on their observed luminosity
function and its evolution, and models of emission and absorption spectra of
quasars; and (4) compact emission line galaxies, based on the observed
distribution of their spectral properties and sizes. The results are presented
in the color system of the Sloan Digital Sky Survey (SDSS), with realistic
photometric error and Galactic extinction. The simulated colors of stars and
quasars are compared with observations in the SDSS system and show good
agreement. The stellar simulation can be used as a tool to analyze star counts
and constrain models of Galactic structure, as well as to identify stars with
unusual colors. The simulation can also be used to establish the quasar target
selection algorithm for the SDSS.
