Name: scFang-rrrrrr-c-ffff.fit for those produced by SSC, psFang-rrrrrr-c-ffff.fit for those produced by PSP, where rrrrrr is the imaging run number, c is the column location in the Imaging Array of the CCD which acquired the data (1-11), and ffff is the field number within the run.
Produced by: ssc, ps
Used by: astrom, ps
Size: 2880 * 37 + 5 * (8454 * Nstars {rounded up to multiple of 2880}) + 7 * (50 * Nstars {rounded up to multiple of 2880}) bytes per file for columns 1-6. 2880 * 7 + 2 * (50 * Nstars {rounded to multiple of 2880}) bytes per file for columns 7-11. Columns 7-11 may not be present. For a field with 100 stars, this gives 4,380.48 Kb per file for a photometric column, and 31.68 Kb per file for an overlap column. Total of 26,441.28 Mb for all 11 columns of a run with 1000 fields.
Archived? Yes, but only the measured stellar parameters.
For overlap columns (columns 7-11), only the measured stellar parameter HDUs are written.
PSP reads the FANG files produced by SSC, corrects the centroids based on the measured PSFs, and writes out new FANG files containing the measured star parameters only.
The order of stamps and stars within each HDU is important. Each stamp/star matches up with the other stamps/stars occupying the same position in the other HDUs.
The order of HDUs is given by the [SPQ]FILTERS and HDUSETS keywords in the PDU. For example, for SSC FANG files for photometric columns:
HDUSETS = 'stamps params quarts' / order of HDU sets in the file SFILTERS= 'r i u z g' / Filters processed for postage stamps. PFILTERS= 'l r i u z g t' / Filters processed for bright star params. QFILTERS= 'r i u z g' / Filters processed for quartile/flats.while for overlap columns:
HDUSETS = 'params' / order of HDU sets in the file PFILTERS= 'o s' / Filters (rows in the imaging camera) processed.Thus, the order of HDUs is:
HDUs (cols 1-6):
1-5:postage stamps for riuzg cutouts
6-12: bright star params for lriuzgt
13-17: flats/quart for riuzg
HDUs (cols 7-11):
1-2: bright star params for o,s (overlap rows)
For FANGs produced by PSP:
HDUSETS = 'params' / order of HDU sets in the file PFILTERS= 'l r i u z g t' / Filters (rows in the imaging camera) processed.NOTE: This is an illegal fits file, as it uses unsigned shorts. Even more illegal, it says "SIMPLE = T". Buyer beware!
SIMPLE = T BITPIX = 8 NAXIS = 0 EXTEND = T VERSION = 'XXX ' / Version of software used. RUN = XXX / Imaging run number. CAMCOL = XXX / Column in imaging camera. SSC_ID = 'XXX ' / SSC pipeline run identifier. PS_ID = 'XXX ' / PSP pipeline run identifier (PSP FANGS only) KO_VER = 'XXX ' / Version of known object catalog used. FIELD = XXX / Field sequence number within the run. HDUSETS = 'stamps params quarts' / Order of HDU sets in the file. SFILTERS= 'r i u z g' / Filters processed for postage stamps. PFILTERS= 'l r i u z g t' / Filters processed for bright star params. QFILTERS= 'r i u z g' / Filters processed for quartile/flats. END
XTENSION= 'BINTABLE' BITPIX = 8 NAXIS = 2 NAXIS1 = 8454 NAXIS2 = XXX PCOUNT = 0 GCOUNT = 1 TFIELDS = 3 EXTNAME = 'STAMP LOC' CAMROW = XXX / Row in imaging camera FILTER = 'XXX ' / Filter for Row in imaging camera PSSIZE = 65 / Postage Stamp Size TSHIFT = XXX / Bias scaling factor FRBIASL = XXX / Left Frame bias x TSHIFT FRBIASR = XXX / Right Frame bias x TSHIFT FROSCNL = XXX / Left Mean Oscn Value x TSHIFT FROSCNR = XXX / Right Mean Oscn Value x TSHIFT TFORM1 = '4225U ' / PostStamp shorts TTYPE1 = 'pixelMap' / Postage Stamp subimage TZERO1 = 32768 TUNIT1 = 'ADUs ' TFORM2 = '1I ' TTYPE2 = 'midRow ' / Frame row (data section) of middle pixel TFORM3 = '1I ' TTYPE3 = 'midCol ' / Frame column (data section) of middle pixel END
-2.5 * log(counts1/counts2)
A bad color is flagged with the value -99.
XTENSION= 'BINTABLE' BITPIX = 8 NAXIS = 2 NAXIS1 = 58 NAXIS2 = XXX PCOUNT = 0 GCOUNT = 1 TFIELDS = 15 EXTNAME = 'STAR LOC' RUN = XXX / Imaging run number. NODE = XXX.XXXXX / Ra of the great circle's ascending node. (deg) INCL = XXX.XXXXX / Great circle's inclination wrt cel eq. (deg) XBORE = XXX.X / Boresight x offset from the array center. (mm) YBORE = XXX.X / Boresight y offset from the array center. (mm) BIAS = XXX / Number of columns of bias per amplifier. OVERSCAN= XXX / Number of columns of overscan per amplifier. FRAME = XXX / Frame number. TAI = XXXXXXXXXX.XX / Number of seconds since Nov 17 1858 0 UT/TAI. RA = XXX.XXXXXX / Right ascension/longitude. (degrees) DEC = XXX.XXXXXX / Declination/latitude. (degrees) SPA = XXX.XXX / Camera col position angle wrt north. (degrees) IPA = XXX.XXX / Instrument rotator position angle. (degrees) IPARATE = XXX.XXXX / Instrument rotator angular velocity. (deg/sec) AZ = XXX.XXXXXX / Azimuth (encoder) of telescope. (degrees) ALT = XXX.XXXXXX / Altitude (encoder) of telescope. (degrees) CAMCOL = XXX / Column in the imaging camera. (astro chips only) CAMROW = XXX / Row in imaging camera FILTER = 'XXX ' / Filter for Row in imaging camera TFORM1 = '1J ' TTYPE1 = 'midRow ' / Frame row of the stamp's middle pixel. TFORM2 = '1J ' TTYPE2 = 'midCol ' / Frame column of the stamp's middle pixel. TFORM3 = '1E ' TTYPE3 = 'rowCentroid' / Row position of star center. TUNIT3 = 'pixels ' TFORM4 = '1E ' TTYPE4 = 'rowCentroidErr' / Row position of star center. (error) TUNIT4 = 'pixels ' TFORM5 = '1E ' TTYPE5 = 'colCentroid' / Column position of star center. TUNIT5 = 'pixels ' TFORM6 = '1E ' TTYPE6 = 'colCentroidErr' / Column position of star center. (error) TUNIT6 = 'pixels ' TFORM7 = '1E ' TTYPE7 = 'rMajor ' / Major axis radius. TUNIT7 = 'pixels ' TFORM8 = '1E ' TTYPE8 = 'rMinor ' / Minor axis radius. TUNIT8 = 'pixels ' TFORM9 = '1E ' TTYPE9 = 'angMajorAxis' / Major axis position angle. TUNIT9 = 'degrees ' TFORM10 = '1E ' TTYPE10 = 'peak ' / Peak of the gaussian fit. TUNIT10 = 'DNs ' TFORM11 = '1E ' TTYPE11 = 'counts ' / Sum of counts over sky. TUNIT11 = 'DNs ' TFORM12 = '1E ' TTYPE12 = 'color ' / Instrumental color. TFORM13 = '1E ' TTYPE13 = 'colorErr' / Instrumental color. (error) TFORM14 = '1J ' TTYPE14 = 'statusFit' / 0=ok, else error. TFORM15 = '1I ' TTYPE15 = 'sscStatus' / 0=ok,1=bad radius,2=bad peak,4=photo only COMMENT / -9=dummy entry (not found on this chip) END
XTENSION= 'BINTABLE' BITPIX = 8 NAXIS = 2 NAXIS1 = 16 NAXIS2 = XXX PCOUNT = 0 GCOUNT = 1 TFIELDS = 4 EXTNAME = 'QFLAT LOC' CAMROW = 1 / Row in imaging camera FILTER = 'XXX ' / Filter for Row in imaging camera TSHIFT = XXX / Quartile scaling factor HISTBINS= XXX / Num bins in quartile hists DBASE = XXX / Maximum delta for hist bases NQCALCL = XXX / Number of quartiles calculated - lo col numbers NQCALCR = XXX / Number of quartiles calculated - hi col numbers FRBIASL = XXX / Left Frame bias x TSHIFT FRBIASR = XXX / Right Frame bias x TSHIFT FRSKYL = XXX / Left Mean Sky Value x TSHIFT FRSKYR = XXX / Right Mean Sky Value x TSHIFT FROSCNL = XXX / Left Mean Oscn Value x TSHIFT FROSCNR = XXX / Right Mean Oscn Value x TSHIFT SKIPPED = XXX / Number of rows ignored AUTHOR = 'Node=sdssid1.fnal.gov Type=photo Cr=1 Bd=0 #=5 Src=CAMERA' TFORM1 = '1J ' TTYPE1 = 'q1 ' / 25th percentile. TUNIT1 = 'ADUs x TSHIFT' TFORM2 = '1J ' TTYPE2 = 'q2 ' / 50th percentile. TUNIT2 = 'ADUs x TSHIFT' TFORM3 = '1J ' TTYPE3 = 'q3 ' / 75th percentile. TUNIT3 = 'ADUs x TSHIFT' TFORM4 = '1J ' TTYPE4 = 'flatVal ' / Flat field value (similar to q2). TUNIT4 = 'ADUs x TSHIFT' END