Exposure level calibration zeropoints, flags, and quality metrics for g-band exposures. The RESID and SCATTER measures that were used to decide if an exposure was "photometric" and to be included in the source catalog.
| Name | Type | Unit | Description |
|---|---|---|---|
| SMF_FN | float64 | J2000 | duplicate of MJD_OBS for historical reasons relating to PS1 heritage |
| MJD_OBS | float64 | J2000 | Modified Julian date of observation |
| ZP | float64 | inst. mag | Per exposure zeropoint to be added to measured instrumental magnitude in order to obtain AB magnitude |
| REASON | int32 | Flag that is zero for ideal photometric conditions used in the photometric calibration (fit) | |
| RESID | float32 | mag | $2.7\sigma_{\rm IQR}$-clipped mean residual flux for calibration stars in the exposure relative to the model flux predicted by the photometric fit. |
| SCATTER | float32 | mag | $2.7\sigma_{\rm IQR}$-clipped standard deviation of the calibration stars residuals |
Time-invariant flat-field for g-band derived on 256 x 256 pixel$^2$ sublocks fit during the photometric calibration. See Jupyter notebook in the release for how to map data format back into focal plane.
CCD level calibration flags and quality metrics for g-band exposures.
| Name | Type | Unit | Description |
|---|---|---|---|
| SMF_FN | char | J2000 | string-ified version of MJD related to PS1 heritage; use MJD_OBS to identify exposures insetad. |
| MJD_OBS | float64 | J2000 | Modified Julian date of observation |
| MNCHIP | float32[64] | mag | mean mag difference between sources detected on this chip, and those sources' mean magnitudes, after subtracting the equivalent offset for the whole exposure; i.e., how consistent is the mean photometry on this chip with that of the exposure? |
| SDCHIP | float32[64] | mag | standard deviation in mag difference between sources detected on this chip and those sources' mean magnitudes |
| NSTARCHIP | int32[64] | number of good detections used on this chip in the photometric calibration process | |
| CHMASK | int32[64] | Flag that is nonzero if a CCD is excluded from the catalog as a result of the photometric calibration. |