Description: Contains metadata related to a difference image constructed by subtracting a stacked image from a single epoch image, or in the case of the MD Survey from a nightly stack (stack made from all exposures in a single filter in a single night). The astrometric calibration of the reference stack is listed. Name Unit Data Type Size Default Value Description diffImageID dimensionless BIGINT 8 NA Unique difference identifier. batchID dimensionless BIGINT 8 NA Internal database batch identifier. surveyID dimensionless TINYINT 1 NA Survey identifier. Details in the Survey table. filterID dimensionless TINYINT 1 NA Filter identifier. Details in the Filter table. diffTypeID dimensionless TINYINT 1 0 Difference type identifier. Details in the DiffType table. frameID dimensionless INT 4 NA Frame/exposure identifier for the postitive image in warp-stack difference images; not populated for stack-stack differences. posImageID dimensionless BIGINT 8 NA Image identifier for the positive image. For warp-stack difference images, this corresponds to the ForcedWarpToImage.forcedWarpID entry. For stack-stack difference images, this corresponds to StackMeta.stackImageID. negImageID dimensionless BIGINT 8 NA Image identifier for the negative image. For warp-stack difference images, this corresponds to the StackMeta.stackImageID entry. ippDiffID dimensionless BIGINT 8 NA IPP diffRun identifier. tessID dimensionless TINYINT 1 0 Tessellation identifier. Details in the TessellationType table. projectionID dimensionless SMALLINT 2 -1 Projection cell identifier. skyCellID dimensionless TINYINT 1 255 Skycell region identifier. photoCalID dimensionless INT 4 NA Photometric calibration identifier. Details in the PhotoCal table. analysisVer dimensionless VARCHAR(100) 100 IPP software analysis release version. md5sum dimensionless VARCHAR(100) 100 IPP MD5 Checksum. detectionThreshold magnitudes REAL 4 -999 Reference magnitude for detection efficiency calculation. expTime seconds REAL 4 -999 Exposure time of positive image. Necessary for converting listed fluxes and magnitudes back to measured ADU counts. psfModelID dimensionless INT 4 -999 PSF model identifier. psfFWHM arcsec REAL 4 -999 Mean PSF full width at half maximum at image center. psfWidMajor arcsec REAL 4 -999 PSF major axis FWHM at image center. psfWidMinor arcsec REAL 4 -999 PSF minor axis FWHM at image center. psfTheta degrees REAL 4 -999 PSF major axis orientation at image center. kernel dimensionless VARCHAR(100) 100 Subtraction kernel. mode dimensionless TINYINT 1 0 Subtraction mode for which input to convolve. numStamps dimensionless INT 4 -999 Number of stamps. stampDevMean dimensionless REAL 4 -999 Mean stamp deviation. stampDevRMS dimensionless REAL 4 -999 RMS stamp deviation. normalization dimensionless REAL 4 -999 Normalization. convolveMax dimensionless REAL 4 -999 Maxiumum convolution fraction. deconvolveMax dimensionless REAL 4 -999 Maximum deconvolution fraction. ctype1 dimensionless VARCHAR(100) 100 Name of astrometric projection in right ascension. ctype2 dimensionless VARCHAR(100) 100 Name of astrometric projection in declination. crval1 degrees FLOAT 8 -999 Right ascension corresponding to reference pixel. crval2 degrees FLOAT 8 -999 Declination corresponding to reference pixel. crpix1 sky pixels FLOAT 8 -999 Reference pixel for right ascension. crpix2 sky pixels FLOAT 8 -999 Reference pixel for declination. cdelt1 degrees/pixel FLOAT 8 -999 Pixel scale in right ascension. cdelt2 degrees/pixel FLOAT 8 -999 Pixel scale in declination. pc001001 dimensionless FLOAT 8 -999 Linear transformation matrix element between image pixel x and right ascension. pc001002 dimensionless FLOAT 8 -999 Linear transformation matrix element between image pixel y and right ascension. pc002001 dimensionless FLOAT 8 -999 Linear transformation matrix element between image pixel x and declination. pc002002 dimensionless FLOAT 8 -999 Linear transformation matrix element between image pixel y and declination. processingVersion dimensionless TINYINT 1 NA Data release version.
