File Formats File Name Conventions File Contents File Sizes WFC3 Dataset Format File Formats File Name Conventions File Contents File Sizes

File Format Overview File formats utilize STIS, NICMOS, and ACS heritage Run-time and archive formats are FITS with image and table extensions Images represented by several data arrays, collectively known as an IMSET (image set) 2 UVIS chip images stored as 2 IMSETs in one file IR MultiAccum readouts stored as multiple IMSETs in one file Individual exposures – including members of CR-Splits, Repeat-Obs, and Dithers – stored in separate files CR-Splits, Repeat-Obs, and Dithers are associated Mosaic members (specified across >1 exposure logsheet line) are not associated February 13, 2001 WFC3 Data Formats

WFC3 will retain ACS and some NICMOS name conventions WFC3 File Names WFC3 will retain ACS and some NICMOS name conventions Suffix Type Contents Cal Class _raw Image Raw science image Uncal _asn Table Association table Uncal,Cal _spt Support file _trl Trailer file _ima Intermediate IR MultiAccum image Cal _flt Calibrated image (UVIS CRSplit=0) _crj CR-cleaned calibrated image (UVIS CRSplit>0 or IR) _sfl Repeat-Obs summed image _dth Dither combined image February 13, 2001 WFC3 Data Formats

Science File Contents IMSET contents UVIS (follows STIS and ACS) Science Image (SCI) Error Image (ERR) Data Quality Flags (DQ) IR (follows NICMOS) Number of Samples (SAMP) Exposure Time (TIME) Primary Header SCI Extension ERR Extension DQ Extension x 2 IMSETs Primary Header SCI Extension ERR Extension DQ Extension SAMP Extension TIME Extension x NSAMP IMSETs February 13, 2001 WFC3 Data Formats

Science File Contents (cont.) RAW UVIS: 2 raw IMSETs from one exposure (1 IMSET per chip) IR: NSAMP raw IMSETs from one exposure IMA IR only: NSAMP calibrated IMSETs from one exposure FLT UVIS only: 2 calibrated IMSETs from one (non-CRSPLIT) exposure CRJ UVIS: 2 calibrated and CR-cleaned IMSETs from multiple CR-SPLIT exposures IR: 1 calibrated and CR-cleaned IMSET from one exposure (CR rejection accomplished via MultiAccum readout combination) February 13, 2001 WFC3 Data Formats

Science File Contents (cont.) SFL UVIS: 2 calibrated and summed IMSETs from Repeat-Obs exposures IR: 1 calibrated and summed IMSET from Repeat-Obs exposures DTH UVIS and IR: 1 calibrated and drizzled IMSET from Dithered exposures February 13, 2001 WFC3 Data Formats

Follows ACS Conventions Association Tables Follows ACS Conventions MEMTYPE* Description EXP-CRJ Input exposure for single CR-combined product PROD-CRJ Single CR-combined output product EXP-CRn Input exposure for CR-combined product n PROD-CRn CR-combined product n EXP-RPT Input exposure for single Repeat-Obs combined product PROD-RPT Repeat-Obs combined output product EXP-RPn Input Repeat-Obs exposure n PROD-RPn Repeat-Obs combined product n EXP-DTH Input exposure for Dither-combined product PROD-DTH Dither-combined output product *CR-Splits and Repeat-Obs are mutually exclusive within a single association February 13, 2001 WFC3 Data Formats

Sample Association Tables CR-SPLIT=3, No Dither CR-SPLIT=2, 2-position Dither MEMNAME MEMTYPE J1xx52ecm EXP-CRJ J1xx52egm J1xx52emm J1xx52011 PROD-CRJ MEMNAME MEMTYPE J1xx52ecm EXP-CR1 J1xx52egm J1xx52011 PROD-CR1 J1xx52emm EXP-CR2 J1xx52eom J1xx52012 PROD-CR2 J1xx52010 PROD-DTH February 13, 2001 WFC3 Data Formats

Sample Association Tables 4-position Dither, CRSPLIT=REPEATOBS=0 MEMNAME MEMTYPE J1xx52ecm EXP-DTH J1xx52edm J1xx52eem J1xx52efm J1xx52010 PROD-DTH February 13, 2001 WFC3 Data Formats

Trailer File Follows ACS Design CALWF3 modules write to explicitly-chosen trailer files Pre-CALWF3 modules (e.g. Generic Conversion, WCS) create and populate individual trailer file for each exposure CALWF3 modules that process individual exposures append to existing individual trailer files CALWF3 modules that process multiple exposures append to concatenated product trailer file (contains log for all members and products) February 13, 2001 WFC3 Data Formats

Keywords UVIS and IR images will use separate sets of keywords Reuse ACS WFC for WFC3 UVIS and NICMOS for WFC3 IR keywords, as appropriate Minor differences between ACS WFC and NICMOS keyword conventions (e.g. “dqicorr” vs. “maskcorr”) resolved by adopting ACS WFC conventions for both UVIS and IR images Keeps WFC3 UVIS consistent with STIS and ACS Keeps WFC3 UVIS consistent with WFC3 IR Results in minor differences between NICMOS and WFC3 IR February 13, 2001 WFC3 Data Formats

WFC3 File Sizes UVIS IR File Type Size (MB) ASN Table <0.1 SPT Image ~0.1 TRL RAW 34 FLT 168 CRJ SFL DTH File Type Size (MB) ASN Table <0.1 SPT Image <1 TRL RAW 33 (max) 1 IMA 168 (max) 2 CRJ 17 SFL DTH 1 2 MB per readout 2 10.5 MB per readout February 13, 2001 WFC3 Data Formats