Reference File Types¶
The reset correction step uses a RESET reference file.
RESET Reference File¶
- REFTYPE
RESET
- Data model
Standard Keywords¶
The following table lists the keywords that are required to be present in all reference files. The first column gives the FITS keyword names. The second column gives the jwst data model name for each keyword, which is useful when using data models in creating and populating a new reference file. The third column gives the equivalent meta tag in ASDF reference file headers, which is the same as the name within the data model meta tree (second column).
FITS Keyword |
Data Model Name |
ASDF meta tag |
|---|---|---|
AUTHOR |
model.meta.author |
author |
DATAMODL |
model.meta.model_type |
model_type |
DATE |
model.meta.date |
date |
DESCRIP |
model.meta.description |
description |
FILENAME |
model.meta.filename |
N/A |
INSTRUME |
model.meta.instrument.name |
instrument: {name} |
PEDIGREE |
model.meta.pedigree |
pedigree |
REFTYPE |
model.meta.reftype |
reftype |
TELESCOP |
model.meta.telescope |
telescope |
USEAFTER |
model.meta.useafter |
useafter |
NOTE: More information on standard required keywords can be found here: Standard Required Keywords
Reference File Format¶
The reset reference files are FITS files with 3 IMAGE extensions and 1 BINTABLE extension. The FITS primary data array is assumed to be empty. The characteristics of the three image extension are as follows:
EXTNAME |
NAXIS |
Dimensions |
Data type |
|---|---|---|---|
SCI |
4 |
ncols x nrows x ngroups x nint |
float |
ERR |
4 |
ncols x nrows x ngroups x nint |
float |
DQ |
2 |
ncols x nrows |
integer |
The DQ_DEF extension contains the bit assignments used in the DQ array. It contains the following 4 columns:
TTYPE |
TFORM |
Description |
|---|---|---|
BIT |
integer |
The bit number, starting at zero |
VALUE |
integer |
The equivalent base-10 value of BIT |
NAME |
string |
The mnemonic name of the data quality condition |
DESCRIPTION |
string |
A description of the data quality condition |
NOTE: For more information on standard bit definitions see: Data Quality Flags.
The SCI and ERR data arrays are 4-D, with dimensions of ncols x nrows x ngroups X nints, where ncols x nrows matches the dimensions of the raw detector readout mode for which the reset applies. The reference file contains the number of NGroups planes required for the correction to be zero on the last plane Ngroups plane. The correction for the first few integrations varies and eventually settles down to a constant correction independent of integration number.