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.