PHOTOMETRIC CALIBRATION OF THE FIRST 1.5 YEARS OF THE PAN-STARRS1 SURVEY

Abstract

We present a precise photometric calibration of the first 1.5 years of\nscience imaging from the Pan-STARRS1 survey (PS1), an ongoing optical survey of\nthe entire sky north of declination -30 degrees in five bands. Building on the\ntechniques employed by Padmanabhan et al. (2008) in the Sloan Digital Sky\nSurvey (SDSS), we use repeat PS1 observations of stars to perform the relative\ncalibration of PS1 in each of its five bands, solving simultaneously for the\nsystem throughput, the atmospheric transparency, and the large-scale detector\nflat field. Both internal consistency tests and comparison against the SDSS\nindicate that we achieve relative precision of <10 mmag in g, r, and i_P1, and\n~10 mmag in z and y_P1. The spatial structure of the differences with the SDSS\nindicates that errors in both the PS1 and SDSS photometric calibration\ncontribute similarly to the differences. The analysis suggests that both the\nPS1 system and the Haleakala site will enable <1% photometry over much of the\nsky.\n