
We need to have consistent behavior when we determine the PSF from the image or load it externally.

Here is a list of the metadata info generated during the psphot analysis (these are mostly stored on the 'analysis' metadata, sometimes in chip and sometimes in readout).

  ANGLE               : PSF Model position angle 
  APLOSS	      : flux lost out of reference aperture
  APMIFIT	      : aperture magnitude - psf fit magnitude (aperture correction
  DAPMIFIT	      : error on APMIFIT
 *EFFECTIVE_AREA      : effective area of the PSF model
  FLIMIT	      : limiting flux (not currently set correctly)
  FSATUR	      : saturation flux (not currently set correctly)
  FWHM_MAJ	      : PSF Model FWHM (Major-Axis)
  FWHM_MIN	      : PSF Model FWHM (Minor-Axis)
  FW_MJ_LQ	      : PSF Model FWHM (Major-Axis lower quartile)
  FW_MJ_SG	      : PSF Model FWHM (Major-Axis sigma)
  FW_MJ_UQ	      : PSF Model FWHM (Major-Axis upper quartile)
  FW_MN_LQ	      : PSF Model FWHM (Minor-Axis lower quartile)
  FW_MN_SG	      : PSF Model FWHM (Minor-Axis sigma)
  FW_MN_UQ	      : PSF Model FWHM (Minor-Axis upper quartile)
  IQ_FW1	      : Moments-based FWHM (Major-Axis)
  IQ_FW1_E	      : Moments-based FWHM (Major-Axis Stdev)
  IQ_FW2	      : Moments-based FWHM (Minor-Axis)
  IQ_FW2_E	      : Moments-based FWHM (Minor-Axis Stdev)
  IQ_M2	  	      : Moments-based shape parameter
  IQ_M2C	      : Moments-based shape parameter
  IQ_M2C_E	      : Moments-based shape parameter
  IQ_M2C_L	      : Moments-based shape parameter
  IQ_M2C_U	      : Moments-based shape parameter
  IQ_M2S	      : Moments-based shape parameter
  IQ_M2S_E	      : Moments-based shape parameter
  IQ_M2S_L	      : Moments-based shape parameter
  IQ_M2S_U	      : Moments-based shape parameter
  IQ_M2_ER	      : Moments-based shape parameter
  IQ_M2_LQ	      : Moments-based shape parameter
  IQ_M2_UQ	      : Moments-based shape parameter
  IQ_M3	  	      : Moments-based shape parameter
  IQ_M3_ER	      : Moments-based shape parameter
  IQ_M3_LQ	      : Moments-based shape parameter
  IQ_M3_UQ	      : Moments-based shape parameter
  IQ_M4	  	      : Moments-based shape parameter
  IQ_M4_ER	      : Moments-based shape parameter
  IQ_M4_LQ	      : Moments-based shape parameter
  IQ_M4_UQ	      : Moments-based shape parameter
  IQ_NSTAR            : Number of sources used to measure moments-based parameters
  MOMENTS_GAUSS_SIGMA : Sigma of Gaussian window used for moments analysis 
  MOMENTS_SX_MAX      : max allowed Mxx (second moment in x) allowed for PSF clump 
  MOMENTS_SY_MAX      : max allowed Myy (second moment in y) allowed for PSF clump 
  MSKY_MAX            : Sky Model max value
  MSKY_MIN            : Sky Model min value
  MSKY_MN             : Sky Model mean value
  MSKY_NX             : Sky Model number of cells (x)
  MSKY_NY             : Sky Model number of cells (y)
  MSKY_SIG            : Sky Model sigma
  NAPMIFIT            : Number of stars used for APMIFIT analysis
  NDET_CR	      : Number of sources classified as 'cosmic ray'
  NDET_EXT	      : Number of sources classified as 'extended'
  NPSFSTAR	      : Number of sources used for PSF model
  NSTARS	      : Total number of sources
  PEAK_THRESHOLD      : threshold of peak detection analysis (saved but not re-used)
  PSF.CLUMP.DX        : size of clump in X
  PSF.CLUMP.DY        : size of clump in Y
  PSF.CLUMP.NREGIONS  : number of PSF clump regions measured for this image
  PSF.CLUMP.X         : center of clump in X
  PSF.CLUMP.Y         : center of clump in Y
  PSFMODEL	      : do we have a valid PSF model?
  PSF_APERTURE        : aperture used to measure the aperture magnitude of PSF sources
  PSF_CLUMP_GRID_SCALE: pixelization size used for PSF clump search 
  PSF_FIT_RADIUS      : size of window used for PSF model fits
  PSF_MAX_NSTARS      : maximum number of sources used to find the PSF model
  PSF_MOMENTS_RADIUS  : size of window used for moments analysis (Gaussian window is applied within this radius)
  SIGMA_SMOOTH        : sigma of kernel used for smoothing to generate the significance 
  SIGNIFICANCE_SCALE_FACTOR : factor needed to adjust the level of the significance image
  SKY_MEAN            : mean of background
  SKY_STDEV	      : stdev of full background image
