WFC3 Dataset Format
•File Formats
•File Name Conventions
•File Contents
•File Sizes
File Format Overview
WFC3 PIPELINE PDR
H. Bushouse
• 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
2
WFC3 File Names
WFC3 PIPELINE PDR
H. Bushouse
WFC3 will retain ACS and some NICMOS name conventions
Suffix
Type
Contents
Cal Class
_raw
Image Raw science image
Uncal
_asn
Table
Uncal,Cal
_spt
Image Support file
Uncal,Cal
_trl
Table
Uncal,Cal
_ima
Image Intermediate IR MultiAccum image
Cal
_flt
Image Calibrated image (UVIS CRSplit=0)
Cal
_crj
Image CR-cleaned calibrated image (UVIS CRSplit>0 or IR) Cal
_sfl
Image Repeat-Obs summed image
Cal
_dth
Image Dither combined image
Cal
February 13, 2001
Association table
Trailer file
WFC3 Data Formats
3
Science File Contents
WFC3 PIPELINE PDR
H. Bushouse
• IMSET contents
– UVIS (follows STIS and ACS)
Primary Header
• Science Image (SCI)
• Error Image (ERR)
• Data Quality Flags (DQ)
SCI Extension
– IR (follows NICMOS)
•
•
•
•
•
February 13, 2001
ERR Extension
x 2 IMSETs
DQ Extension
Primary Header
Science Image (SCI)
Error Image (ERR)
Data Quality Flags (DQ)
Number of Samples (SAMP)
Exposure Time (TIME)
WFC3 Data Formats
SCI Extension
ERR Extension
DQ Extension
x NSAMP
IMSETs
SAMP Extension
TIME Extension
4
Science File Contents (cont.)
WFC3 PIPELINE PDR
H. Bushouse
• 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 CRSPLIT exposures
– IR: 1 calibrated and CR-cleaned IMSET from one exposure (CR
rejection accomplished via MultiAccum readout combination)
February 13, 2001
WFC3 Data Formats
5
Science File Contents (cont.)
WFC3 PIPELINE PDR
H. Bushouse
• 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
6
Association Tables
WFC3 PIPELINE PDR
H. Bushouse
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
7
Sample Association Tables
WFC3 PIPELINE PDR
H. Bushouse
CR-SPLIT=3, No Dither
CR-SPLIT=2, 2-position Dither
MEMNAME
MEMTYPE
MEMNAME
MEMTYPE
J1xx52ecm
EXP-CRJ
J1xx52ecm
EXP-CR1
J1xx52egm
EXP-CRJ
J1xx52egm
EXP-CR1
J1xx52emm
EXP-CRJ
J1xx52011
PROD-CR1
J1xx52011
PROD-CRJ
J1xx52emm
EXP-CR2
J1xx52eom
EXP-CR2
J1xx52012
PROD-CR2
J1xx52010
PROD-DTH
February 13, 2001
WFC3 Data Formats
8
Sample Association Tables
WFC3 PIPELINE PDR
H. Bushouse
4-position Dither, CRSPLIT=REPEATOBS=0
February 13, 2001
MEMNAME
MEMTYPE
J1xx52ecm
EXP-DTH
J1xx52edm
EXP-DTH
J1xx52eem
EXP-DTH
J1xx52efm
EXP-DTH
J1xx52010
PROD-DTH
WFC3 Data Formats
9
Trailer File
WFC3 PIPELINE PDR
H. Bushouse
• 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
10
Keywords
WFC3 PIPELINE PDR
H. Bushouse
• 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
11
WFC3 File Sizes
UVIS
File
Type
WFC3 PIPELINE PDR
H. Bushouse
IR
File
Size (MB)
Type
Size (MB)
ASN
Table
<0.1
ASN
Table
<0.1
SPT
Image
~0.1
SPT
Image
<1
TRL
Table
<0.1
TRL
Table
<0.1
RAW
Image
34
RAW
Image
33 (max) 1
FLT
Image
168
IMA
Image
168 (max) 2
CRJ
Image
168
CRJ
Image
17
SFL
Image
168
SFL
Image
17
DTH
Image
168
DTH
Image
17
1
2 MB per readout
2 10.5 MB per readout
February 13, 2001
WFC3 Data Formats
12