| Version 6 (modified by , 16 years ago) ( diff ) |
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General notes
Though efforts have been made to avoid this from occurring, where header keyword names are longer than the usual 8 character maximum, the HIERARCH convention will be used.
Celestial coordinates are in ICRS.
Magnitudes are AB magnitudes (flux zero point is 3631 Jy).
Unless otherwise noted, error values are statistical only, and include no contribution by systematic errors.
Primary header
The primary header will not contain any information beyond that written automatically by cfitsio, and is present only for compliance with the FITS standard.
FITS table
The FITS table will include all detections within an exposure.
Duplicates from overlapping skycells will have been filtered out by IPP, with the measurements from the source closest to the centre of a skycell included (and all others discarded).
Header
The header will contain information relevant to the exposure as a whole.
- Version information
- SWSOURCE (string): source of software (e.g., "60eb6cdc-a59c-4636-a4e0-dba66a9721fd")
- SWVERSN (string): version of software (e.g., "trunk/ppMops@24658")
- Provenance information
- EXP_NAME (string): Exposure name (e.g., "o1234g5678")
- EXP_ID (S64): Exposure identifier
- CHIP_ID (S64): Chip stage identifier
- CAM_ID (S64): Camera stage identifier
- FAKE_ID (S64): Fake stage identifier
- WARP_ID (S64): Warp stage identifier
- DIFF_ID (S64): Diff stage identifier
- DIFF_POS (boolean): Sense of subtraction; T for forward, F for backward
- Exposure details
- MJD-OBS (F64): TAI MJD of exposure mid-point
- RA (string): Reported Right Ascension of telescope boresight, sexagesimal hours (e.g., "12:34:56.789")
- DEC (string): Reported Declination of telescope boresight, sexagesimal degrees (e.g., "-12:34:56.78")
- TEL_ALT (F64): Reported telescope altitude, degrees
- TEL_AZ (F64): Reported telescope azimuth, degrees
- EXPTIME (F32): Exposure time, seconds
- ROTANGLE (F64): Rotator angle, degrees
- FILTER (string): Filter name (e.g., "r.00000")
- AIRMASS (F32): Airmass for exposure
- OBSCODE (string): IAU observatory code (i.e., "F51" for PS1)
- SEEING (F32): Measured seeing at diff stage, arcsec
- MAGZP (F32): Magnitude zero point
- MAGZPERR (F32): Error in magnitude zero point
- ASTRORMS (F32): RMS of astrometric fit, arcsec
- Detection efficiency
- DE_MAGnn (F32): Magnitude (calibrated) for detection efficiency
- DE_EFFnn (F32): Detection efficiency (0..1)
Current limitations
The IPP is not yet calculating detection efficiencies (it is still being developed). Further, it is not yet clear how to merge the detection efficiency measurements for different skycells. Until these issues are resolved, the detection efficiency values will be fake.
Differences from original ICD
- SWSOURCE, SWVERSN has replaced TABLEVER which was never defined
- All of the "Provenance information" has replaced FPA_ID, for better tracking of the source of each detection
- SEEING and MAGZP added as indicators of the quality of the exposure
- MAGZPERR added to make absolute (i.e., across exposures) magnitude errors more accurate
- ASTRORMS added to make absolute (i.e., across exposures) astrometry errors more accurate
- DE_MAGnn and DE_EFFnn replace DE1 through DE10, which were never well defined
- Removed LIMITMAG, which was never well defined, and is unnecessary given the DE_MAGnn and DE_EFFnn
Table
The table will contain information relevant to the individual detections within the exposure.
- RA (F64): Right Ascension of detection centre, degrees
- RA_ERR (F64): Error in RA, degrees
- DEC (F64): Declination of detection centre, degrees
- DEC_ERR (F64): Error in DEC, degrees
- MAG (F32): Calibrated magnitude of detection
- MAG_ERR (F32): Error in MAG
- PSF_CHI2 (F32): chi2 of PSF fit
- PSF_DOF (S32): Degrees of freedom of PSF fit
- CR_SIGNIFICANCE (F32): Significance of CR
- EXT_SIGNIFICANCE (F32): Significance of extendedness
- PSF_MAJOR (F32): PSF major axis (pixels)
- PSF_MINOR (F32): PSF minor axis (pixels)
- PSF_THETA (F32): PSF position angle (deg on chip)
- PSF_QUALITY (F32): PSF quality factor
- PSF_NPIX (S32): Number of pixels in PSF
- MOMENTS_XX (F32): xx moment
- MOMENTS_XY (F32): xy moment
- MOMENTS_YY (F32): yy moment
- N_POS (S32): Number of positive pixels
- F_POS (F32): Fraction of positive pixels
- RATIO_BAD (F32): Ratio of positive pixels to negative
- RATIO_MASK (F32): Ratio of positive pixels to masked
- RATIO_ALL (F32): Ratio of positive pixels to all
- FLAGS (S32): IPP detection flags, bit mask
- DIFF_SKYFILE_ID (S64): IPP diff_skyfile_id for source
Current limitations
The IPP is not yet fitting trails to sources in the difference images. Until this is being done, the ANGLE, ANGLE_ERR, LENGTH and LENGTH_ERR values will be zero.
The value being written as STARPSF is EXT_NSIGMA from the IPP CMF files; it is not clear that this is what MOPS wants, but this is probably irrelevant until the trail fitting has been implemented.
Differences from original ICD
- RA_DEG, DEC_DEG renamed RA, DEC to match apparent naming policy
- *_SIG renamed *_ERR to be more clear
- ANG, ANG_SIG, LEN, LEN_SIG removed; these can be calculated from the moments
- FLUX, FLUX_SIG renamed MAG, MAG_ERR since IPP writes magnitudes
- FLAGS added to allow additional weeding out of bad detections
- DIFF_SKYFILE_ID added to allow trace back to IPP diff skyfile, for postage stamps
- STARPSF renamed EXT_SIGNIFICANCE to be more clear
- Added PSF_CHI2, PSF_DOF, CR_SIGNIFICANCE, PSF_MAJOR, PSF_MINOR, PSF_THETA, PSF_QUALITY, PSF_NPIX, MOMENTS_XX, MOMENTS_XY, MOMENTS_YY for more complete data on each detection
- Added N_POS, F_POS, RATIO_BAD, RATIO_MASK, RATIO_ALL for better weeding out of bad subtractions
Example
XTENSION= 'BINTABLE' / binary table extension BITPIX = 8 / 8-bit bytes NAXIS = 2 / 2-dimensional binary table NAXIS1 = 120 / width of table in bytes NAXIS2 = 42032 / number of rows in table PCOUNT = 0 / size of special data area GCOUNT = 1 / one data group (required keyword) TFIELDS = 25 / number of fields in each row TTYPE1 = 'RA ' / label for field 1 TFORM1 = '1D ' / data format of field: 8-byte DOUBLE TTYPE2 = 'RA_ERR ' / label for field 2 TFORM2 = '1D ' / data format of field: 8-byte DOUBLE TTYPE3 = 'DEC ' / label for field 3 TFORM3 = '1D ' / data format of field: 8-byte DOUBLE TTYPE4 = 'DEC_ERR ' / label for field 4 TFORM4 = '1D ' / data format of field: 8-byte DOUBLE TTYPE5 = 'MAG ' / label for field 5 TFORM5 = '1E ' / data format of field: 4-byte REAL TTYPE6 = 'MAG_ERR ' / label for field 6 TFORM6 = '1E ' / data format of field: 4-byte REAL TTYPE7 = 'PSF_CHI2' / label for field 7 TFORM7 = '1E ' / data format of field: 4-byte REAL TTYPE8 = 'PSF_DOF ' / label for field 8 TFORM8 = '1J ' / data format of field: 4-byte INTEGER TTYPE9 = 'CR_SIGNIFICANCE' / label for field 9 TFORM9 = '1E ' / data format of field: 4-byte REAL TTYPE10 = 'EXT_SIGNIFICANCE' / label for field 10 TFORM10 = '1E ' / data format of field: 4-byte REAL TTYPE11 = 'PSF_MAJOR' / label for field 11 TFORM11 = '1E ' / data format of field: 4-byte REAL TTYPE12 = 'PSF_MINOR' / label for field 12 TFORM12 = '1E ' / data format of field: 4-byte REAL TTYPE13 = 'PSF_THETA' / label for field 13 TFORM13 = '1E ' / data format of field: 4-byte REAL TTYPE14 = 'PSF_QUALITY' / label for field 14 TFORM14 = '1E ' / data format of field: 4-byte REAL TTYPE15 = 'PSF_NPIX' / label for field 15 TFORM15 = '1J ' / data format of field: 4-byte INTEGER TTYPE16 = 'MOMENTS_XX' / label for field 16 TFORM16 = '1E ' / data format of field: 4-byte REAL TTYPE17 = 'MOMENTS_XY' / label for field 17 TFORM17 = '1E ' / data format of field: 4-byte REAL TTYPE18 = 'MOMENTS_YY' / label for field 18 TFORM18 = '1E ' / data format of field: 4-byte REAL TTYPE19 = 'N_POS ' / label for field 19 TFORM19 = '1J ' / data format of field: 4-byte INTEGER TTYPE20 = 'F_POS ' / label for field 20 TFORM20 = '1E ' / data format of field: 4-byte REAL TTYPE21 = 'RATIO_BAD' / label for field 21 TFORM21 = '1E ' / data format of field: 4-byte REAL TTYPE22 = 'RATIO_MASK' / label for field 22 TFORM22 = '1E ' / data format of field: 4-byte REAL TTYPE23 = 'RATIO_ALL' / label for field 23 TFORM23 = '1E ' / data format of field: 4-byte REAL TTYPE24 = 'FLAGS ' / label for field 24 TFORM24 = '1J ' / data format of field: 4-byte INTEGER TZERO24 = 2147483648 / offset for unsigned integers TSCAL24 = 1 / data are not scaled TTYPE25 = 'DIFF_SKYFILE_ID' / label for field 25 TFORM25 = '1K ' / data format of field: 8-byte INTEGER SWSOURCE= '60eb6cdc-a59c-4636-a4e0-dba66a9721fd' / Software source SWVERSN = 'branches/pap_mops/ppMops@25227' / Software version HISTORY ppMops at 2009-09-02T03:48:46.695783 HISTORY psLib version: branches/pap_mops/psLib@25227 HISTORY psLib source: 60eb6cdc-a59c-4636-a4e0-dba66a9721fd HISTORY ppMops version: branches/pap_mops/ppMops@25227 HISTORY ppMops source: 60eb6cdc-a59c-4636-a4e0-dba66a9721fd EXP_NAME= 'o4995g0129o' / Exposure name EXP_ID = 77164 / Exposure identifier CHIP_ID = 24019 / Chip stage identifier CAM_ID = 17726 / Cam stage identifier FAKE_ID = 10227 / Fake stage identifier WARP_ID = 8842 / Warp stage identifier DIFF_ID = 19219 / Diff stage identifier DIFF_POS= F / Positive subtraction? MJD-OBS = 54995.4740598313 / MJD of exposure midpoint RA = '18:25:01.988' / Right Ascension of boresight DEC = '-17:20:40.069' / Declination of boresight TEL_ALT = 51.951873 / Telescope altitude TEL_AZ = 179.483883 / Telescope azimuth EXPTIME = 38. / Exposure time (sec) ROTANGLE= 333.1039 / Rotator position angle FILTER = 'r.00000 ' / Filter name AIRMASS = 1.269 / Airmass of exposure OBSCODE = 'F51 ' / IAU Observatory code SEEING = 1.678401 / Mean seeing MAGZP = 28.65226 / Magnitude zero point MAGZPERR= 0.353063 / Error in magnitude zero point ASTRORMS= 0.3111496 / RMS of astrometric fit EXTNAME = 'MOPS_TRANSIENT_DETECTIONS' END
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PSDC-940-005.pdf
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IPP-MOPS ICD
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