Pan-STARRS Photometric and Astrometric Calibration

Abstract

We present the details of the photometric and astrometric calibration of the Pan-STARRS1 3πSurvey. The photometric goals were to reduce the systematic effects introduced by the camera and detectors, and to place all of the observations onto a photometric system with consistent zero-points over the entire area surveyed, the ≈30,000 deg 2 north of δ=−30°. Using external comparisons, we demonstrate that the resulting photometric system is consistent across the sky to between 7 and 12.4 mmag depending on the filter. For bright stars, the systematic error floor for individual measurements is (σ g , σ r , σ i , σ z , σ y)=(14, 14, 15, 15, 18) mmag. The astrometric calibration compensates for similar systematic effects so that positions, proper motions, and parallaxes are reliable as well. The bright-star systematic error floor for individual astrometric measurements is 16 mas. The Pan-STARRS Data Release 2 (DR2) astrometric system is tied to the Gaia DR1 coordinate frame with a systematic uncertainty of ∼5 mas.

The Pan-STARRS1 Database and Data Products

“…The DVO (Magnier & Cuillandre 2004;Magnier et al 2020c) is a database that tracks the measurements of astronomical sources detected in the various types of images and associates them into unique astronomical objects based on positional coincidence. This database system also tracks the metadata for each image that provided the measurements.…”

Pan-STARRS Pixel Processing: Detrending, Warping, Stacking

“…In addition to this flat field applied to the individual images, the "ubercal" analysis-in which photometric data are used define image zero points (Schlafly et al 2012;Magnier et al 2020b) and in turn used used to calibrate the database of all detections-constructs "in catalog" flat-field corrections. Although a single set of image flat fields was used for the PV3 processing of the entire 3π Survey, five separate "seasons" of database flat fields were needed to ensure proper calibration.…”

“…DR1 contains the results of the third full reduction of the Pan-STARRS 3π Survey archival data, identified as PV3. Previous reductions (PV0, PV1, PV2; see Magnier et al 2020a) were used internally for pipeline optimization and the development of the initial photometric and astrometric reference catalog (Magnier et al 2020b). The products from these reductions were not publicly released but have been used to produce a wide range of scientific papers from the Pan-STARRS1 Science Consortium members (Chambers et al 2017).…”

astrosource: automating optical astronomy measurement, calibration and analysis for variable stellar sources from provided photometry

“…• Provide the variability of all stars within the dataset as a catalogue to facilitate variable source identification. • Calibrate the ensemble set to known stars in the field from APASS (Henden et al (2015)), SDSS (Alam et al (2015)), PanSTARRS (Magnier et al (2016)) or Skymapper (Wolf et al (2018)) depending on filter selection and declination. • Extract the photometric measurements and plot lightcurves of provided target stars.…”