FITS images , one image in the primary HDU: NAXIS 2 (mono or a raw Bayer mosaic) or 3
(colour planes), BITPIX 8, 16, 32, -32 or -64. Physical values are BZERO + BSCALE x raw, in ADU, not scaled to 0 to 1. Any other BITPIX stops with unsupported BITPIX.Files ending .fits, .fit or .fts (any case) when you give a folder. A file named
directly is read whatever its name.
Rows are kept in the order stored in the file (row 0 is the first row of the data), as
astropy does, so pixel coordinates agree with Python tools and with the WCS keywords.
ROWORDER is carried but not interpreted.
A star catalogue: see The star catalogue file .
File Written by Format
calibrated, registered, stacked, drizzled, background-corrected, stretched, starless, solved and colour-calibrated images, masters, models, masks, coverage and weight maps the matching command 32-bit float FITS (BITPIX -32), the input's header carried over, plus the keywords below --previewstretch, starless8-bit PNG --stars-out of photocalphotocalCSV: x,y,g,bp_rp,flux_r,flux_g,flux_b,used --reportstack, drizzlethe per-frame table as text --stars-out of starlessstarlessFITS (original minus starless)
The input is never changed.
Keyword Used for
IMAGETYP, FRAMETYPa single calibration file whose type says it is a master is used as it is EXPTIME, EXPOSUREdark scaling (--scale-dark exposure), EXPTOTAL CCD-TEMP, GAIN, OFFSET, XBINNING, FILTERcarried through; not interpreted BAYERPAT, XBAYROFF, YBAYROFFthe Bayer pattern (RGGB, GRBG, GBRG, BGGR), applied to the array as stored, shifted by the offsets RA, DEC, OBJCTRA, OBJCTDECthe starting position of solve (degrees, or sexagesimal text) FOCALLEN, XPIXSZthe starting pixel scale of solve: 206.265 x pixel size in micron / focal length in mm CTYPE1/2, CRVAL1/2, CRPIX1/2, CD, PC, CDELT, CROTA2 and the A_, B_ SIP familiesan existing world coordinate system (TAN, TAN-SIP) STRETCH and the STR... cardsstretch --invertBIASSUB, FLATNORM, PEDESTAL, NCOMBINEmaster frames: whether the bias is already out of a dark, how a flat was normalised
Keyword Written by Meaning
IMAGETYPcalibrate, stack Master Dark, Master Flat, Calibrated Light, Master LightNCOMBINE, EXPTOTALmasters, stack frames combined, and the summed exposure in seconds BIASSUBmaster dark T when the master bias was subtracted firstSTACKREF, STACKALGstack reference frame number; the rejection and weights DRIZSCL, DRIZPIXF, DRIZREJdrizzle scale, pixfrac and rejection STRETCH, STRBLACK, STRWHITE, STRMID, STRBETA, STRGS, STRGB, STRGSP, STRGLP, STRGHPstretch the curve and its parameters, so --invert can undo it WCSAXES, CTYPE1/2, CUNIT1/2, CRVAL1/2, CRPIX1/2, CD1_1 to CD2_2, RADESYS, EQUINOX, and the SIP terms when usedsolve the world coordinate system PCCGAINR/G/B, PCCOFFR/G/Bphotocal gains and offsets applied HISTORYevery command what was done and with which numbers
Cards the writer generates itself (SIMPLE, BITPIX, NAXIS, NAXIS1 to 3, EXTEND,
BZERO, BSCALE, BLANK, END) are never copied from an input header.