  Y -band is a broad passband that is centered at ~ 1 micron. It is becoming a
new, popular window for extragalactic study especially for observation of red
objects thanks to recent CCD technology developments. In order to better
understand the general characteristics of objects in Y -band, and to
investigate the promise of Y -band observations with small telescopes, we
carried out imaging observation of several extragalactic fields, brown dwarfs
and high redshift quasars with Y -band filter at the Mt. Lemmon Optical
Astronomy Observatory and the Maidanak observatory. From our observations, we
constrain the bright end of the galaxy and the stellar number counts in Y
-band. Also, we test the usefulness of high redshift quasar (z > 6) selection
via i-z-Y color-color diagram, to demonstrate that the i-z-Y color-color
diagram is effective for the selection of high redshift quasars even with a
conventional optical CCD camera installed at a 1-m class telescope.
