This describes the columns and flags in the smf/cmf files. They are listed in psModules/src/objects/pmSourceIO_CMF_PS1_V1.c, this is a slightly more descriptive version.

Columns

  • IPP_IDET - detection id (increment from 0 per chip - gaps are from magic)
  • X_PSF -position (in pixels
  • Y_PSF -position in pixels
  • X_PSF_SIGMA -position sigma
  • Y_PSF_SIGMA -position sigma
  • POSANGLE - position angle of the instrument coordinate system at source (ie, the angle between north and the y-axis) in degrees
  • PLTSCALE - plate-scale at the source position (it varies across the exposure!) in arcsec
  • PSF_INST_MAG - PSF Instrumental mag
  • PSF_INST_MAG - error for that
  • AP_MAG - aperture mag
  • AP_MAG_RADIUS - aperture mag radius (pixels)
  • PEAK_FLUX_AS_MAG - as it says, it is the flux (counts/pixel) for the peak pixel expressed as an instrumental magnitude (-2.5*log(flux))
  • CAL_PSF_MAG - calibrated PSF MAG
  • CAL_PS_MAG_SIG - error
  • RA_PSF - ra
  • DEC_PSF - dec
  • SKY - background in counts (DN, not electrons)
  • SKY_SIGMA -error
  • PSF_CHISQ - chisq of psf
  • CR_NSIGMA - cosmic ray
  • EXT_NSIGMA - extended source
  • PSF_MAJOR - major axis (pixel)
  • PSF_MINOR - minor axis (pixel)
  • PSF_THETA - angle
  • PSF_QF - the psf-weighted fraction of unmasked pixels:
    • \Sum_i (psf_i * !masked) / \Sum_i (psf_i)
  • PSF_NDOF - number of degrees of freedom for the fit -- for the diff detections, the only free parameter is the flux, so N_DOF = N_PIX - 1; in other cases, there may be more parameters (eg, position, size, etc).
  • PSF_NPIX - number of pixels for fit
  • MOMENTS_XX - second moment in x:
    • \Sum ((x_i - x_o)^2 f_i) / \Sum (f_i) where x_o is the centroid \Sum (x_i f_i) / \Sum f_i
  • MOMENTS_XY - second moment in xy:
    • \Sum ((x_i - x_o)(y_i - y_o)^2 f_i) / \Sum (f_i)
  • MOMENTS_YY - second moment in xy
    • \Sum ((y_i - y_o)^2 f_i) / \Sum (f_i)
  • FLAGS - see below
  • N_FRAMES - this is not currently set, but it is supposed to have the value of the number of input images overlapping the center of the source (for warp-warp diff, it would be 2, for a single image it would be 1, for a stack it may be something else).
  • PADDING - a dummy block of data needed to fit the rows into 8-byte boundaries (this lets me read into structures as a bulk byte read operation).

Flags

DEFAULT 0 Initial value: resets all bits
PSFMODEL1 Source fitted with a psf model (linear or non-linear)
EXTMODEL2 Source fitted with an extended-source model
FITTED4 Source fitted with non-linear model (PSF or EXT; good or bad)
FITFAIL8 Fit (non-linear) failed (non-converge, off-edge, run to zero)
POORFIT16 Fit succeeds, but low-SN, high-Chisq, or large (for PSF -- drop?)
PAIR 32 Source fitted with a double psf
PSFSTAR64 Source used to define PSF model
SATSTAR128 Source model peak is above saturation
BLEND 256 Source is a blend with other sourcers
EXTERNALPOS" 512 Source based on supplied input position
BADPSF 1024 Failed to get good estimate of object's PSF
DEFECT 2048 Source is thought to be a defect
SATURATED4096 Source is thought to be saturated pixels (bleed trail)
CR_LIMIT 8192 Source has crNsigma above limit
EXT_LIMIT 16384 Source has extNsigma above limit
MOMENTS_FAILURE 32768 could not measure the moments
SKY_FAILURE 65536 could not measure the local sky
SKYVAR_FAILURE 131072 could not measure the local sky variance
MOMENTS_SN 262144 moments not measured due to low S/N
BIG_RADIUS 1048576 poor moments for small radius, try large radius
AP_MAGS 2097152 source has an aperture magnitude
BLEND_FIT 4194304 source was fitted as a blend
EXTENDED_FIT8388608full extended fit was used
EXTENDED_STATS16777216extended aperture stats calculated
LINEAR_FIT 33554432source fitted with the linear fit
NONLINEAR_FIT67108864 source fitted with the non-linear fit
RADIAL_FLUX134217728radial flux measurements calculated
SIZE_SKIPPED268435456size could not be determined
ON_SPIKE536870912peak lands on diffraction spike
ON_GHOST1073741824peak lands on ghost or glint
OFF_CHIP2147483648peak lands off edge of chip
NOCAL4294967296detection ignored for this analysis (photcode, time range) -- internal only
POOR_PHOTOM8589934592detection is photometry outlier
SKIP_PHOTOM17179869184detection was ignored for photometry measurement
MEAS_AREA34359738368detection near image edge
POOR_ASTROM68719476736detection is astrometry outlier
SKIP_ASTROM137438953472detection was ignored for astrometry measurement
USED_OBJ274877906944detection was used during opdate objects
USED_CHIP549755813888detection was used during update chips
BLEND_MEAS1099511627776detection is within radius of multiple objects
BLEND_OBJ2199023255552multiple detections within radius of object
BLEND_MEAS_X17592186044416detection is within radius of multiple objects across catalogs
ARTIFACT35184372088832detection is thought to be non-astronomical