A Y-BAND LOOK OF THE SKY WITH 1-M CLASS TELESCOPES

Y -band is a broad passband that is centered at ~1 μm. It is becoming a new, popular window for extragalactic study especially for observations of red objects thanks to recent CCD technology de-velopments. 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 observa-tions 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. We also 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.