| | 1 | == General notes == |
| | 2 | |
| | 3 | Though efforts have been made to avoid this from occurring, where |
| | 4 | header keyword names are longer than the usual 8 character maximum, |
| | 5 | the HIERARCH convention will be used. |
| | 6 | |
| | 7 | Celestial coordinates are in ICRS. |
| | 8 | |
| | 9 | Magnitudes are AB magnitudes (flux zero point is 3631 Jy). |
| | 10 | |
| | 11 | Unless otherwise noted, error values are statistical only, and include |
| | 12 | no contribution by systematic errors. |
| | 13 | |
| | 14 | == Primary header == |
| | 15 | |
| | 16 | The primary header will not contain any information beyond that |
| | 17 | written automatically by cfitsio, and is present only for compliance |
| | 18 | with the FITS standard. |
| | 19 | |
| | 20 | == FITS table == |
| | 21 | |
| | 22 | The FITS table will include all detections within an exposure. |
| | 23 | |
| | 24 | Duplicates from overlapping skycells will have been filtered out by |
| | 25 | IPP, with the measurements from the source closest to the centre of a |
| | 26 | skycell included (and all others discarded). |
| | 27 | |
| | 28 | === Header === |
| | 29 | |
| | 30 | The header will contain information relevant to the exposure as a whole. |
| | 31 | |
| | 32 | * Version information |
| | 33 | * SWSOURCE (string): source of software (e.g., "60eb6cdc-a59c-4636-a4e0-dba66a9721fd") |
| | 34 | * SWVERSN (string): version of software (e.g., "trunk/ppMops@24658") |
| | 35 | |
| | 36 | * Provenance information |
| | 37 | * EXP_NAME (string): Exposure name (e.g., "o1234g5678") |
| | 38 | * EXP_ID (S64): Exposure identifier |
| | 39 | * CHIP_ID (S64): Chip stage identifier |
| | 40 | * CAM_ID (S64): Camera stage identifier |
| | 41 | * FAKE_ID (S64): Fake stage identifier |
| | 42 | * WARP_ID (S64): Warp stage identifier |
| | 43 | * DIFF_ID (S64): Diff stage identifier |
| | 44 | * DIFF_POS (boolean): Sense of subtraction; T for forward, F for backward |
| | 45 | |
| | 46 | * Exposure details |
| | 47 | * MJD-OBS (F64): TAI MJD of exposure mid-point |
| | 48 | * RA (string): Reported Right Ascension of telescope boresight, sexagesimal hours (e.g., "12:34:56.789") |
| | 49 | * DEC (string): Reported Declination of telescope boresight, sexagesimal degrees (e.g., "-12:34:56.78") |
| | 50 | * TEL_ALT (F64): Reported telescope altitude, degrees |
| | 51 | * TEL_AZ (F64): Reported telescope azimuth, degrees |
| | 52 | * EXPTIME (F32): Exposure time, seconds |
| | 53 | * ROTANGLE (F64): Rotator angle, degrees |
| | 54 | * FILTER (string): Filter name (e.g., "r.00000") |
| | 55 | * AIRMASS (F32): Airmass for exposure |
| | 56 | * OBSCODE (string): IAU observatory code (i.e., "F51" for PS1) |
| | 57 | * SEEING (F32): Measured seeing at diff stage, arcsec |
| | 58 | * MAGZP (F32): Magnitude zero point |
| | 59 | * MAGZPERR (F32): Error in magnitude zero point |
| | 60 | * ASTRORMS (F32): RMS of astrometric fit, arcsec |
| | 61 | |
| | 62 | * Detection efficiency |
| | 63 | * DE_MAGnn (F32): Magnitude (calibrated) for detection efficiency |
| | 64 | * DE_EFFnn (F32): Detection efficiency (0..1) |
| | 65 | |
| | 66 | ==== Current limitations ==== |
| | 67 | |
| | 68 | The IPP is not yet calculating detection efficiencies (it is still |
| | 69 | being developed). Further, it is not yet clear how to merge the |
| | 70 | detection efficiency measurements for different skycells. Until these |
| | 71 | issues are resolved, the detection efficiency values will be fake. |
| | 72 | |
| | 73 | ==== Differences from original ICD ==== |
| | 74 | |
| | 75 | * SWSOURCE, SWVERSN has replaced TABLEVER which was never defined |
| | 76 | * All of the "Provenance information" has replaced FPA_ID, for better tracking of the source of each detection |
| | 77 | * SEEING and MAGZP added as indicators of the quality of the exposure |
| | 78 | * MAGZPERR added to make absolute (i.e., across exposures) magnitude errors more accurate |
| | 79 | * ASTRORMS added to make absolute (i.e., across exposures) astrometry errors more accurate |
| | 80 | * DE_MAGnn and DE_EFFnn replace DE1 through DE10, which were never well defined |
| | 81 | |
| | 82 | === Table === |
| | 83 | |
| | 84 | The table will contain information relevant to the individual |
| | 85 | detections within the exposure. |
| | 86 | |
| | 87 | * RA (F64): Right Ascension of detection centre, degrees |
| | 88 | * RA_ERR (F64): Error in RA, degrees |
| | 89 | * DEC (F64): Declination of detection centre, degrees |
| | 90 | * DEC_ERR (F64): Error in DEC, degrees |
| | 91 | * MAG (F32): Calibrated magnitude of detection |
| | 92 | * MAG_ERR (F32): Error in MAG |
| | 93 | * STARPSF (F32): A PSF/extended source separator |
| | 94 | * ANGLE (F64): Angle of trail fit to source, degrees E of N |
| | 95 | * ANGLE_ERR (F64): Error in ANGLE, degrees |
| | 96 | * LENGTH (F32): Length of trail fit to source, degrees |
| | 97 | * LENGTH_ERR (F32): Error in LENGTH, degrees |
| | 98 | * FLAGS (S32): IPP detection flags, bit mask |
| | 99 | * DIFF_SKYFILE_ID (S64): IPP diff_skyfile_id for source |
| | 100 | |
| | 101 | ==== Current limitations ==== |
| | 102 | |
| | 103 | The IPP is not yet fitting trails to sources in the difference images. |
| | 104 | Until this is being done, the ANGLE, ANGLE_ERR, LENGTH and LENGTH_ERR |
| | 105 | values will be zero. |
| | 106 | |
| | 107 | The value being written as STARPSF is EXT_NSIGMA from the IPP CMF |
| | 108 | files; it is not clear that this is what MOPS wants, but this is |
| | 109 | probably irrelevant until the trail fitting has been implemented. |
| | 110 | |
| | 111 | ==== Differences from original ICD ==== |
| | 112 | |
| | 113 | * RA_DEG, DEC_DEG renamed RA, DEC to match apparent naming policy |
| | 114 | * *_SIG renamed *_ERR to be more clear |
| | 115 | * ANG, ANG_SIG, LEN, LEN_SIG spelled out as ANGLE, ANGLE_ERR, LENGTH, LENGTH_ERR |
| | 116 | * FLUX, FLUX_SIG renamed MAG, MAG_ERR since IPP writes magnitudes |
| | 117 | * FLAGS added to allow additional weeding out of bad detections |
| | 118 | * DIFF_SKYFILE_ID added to allow trace back to IPP diff skyfile, for postage stamps |
| | 119 | |
