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

2. 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

3. 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

4. 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

5. 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

6. 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

7. 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

8. 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

9. 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

10. 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

11. 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

12. 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
MB per readout
February 13, 2001
WFC3 Data Formats