Barycentric X component of the JWST velocity vector, in km/s, at the mid-point of the exposure.
| Attribute | Value |
|---|---|
| data type | float |
| enumerated Values | not defined |
| units | km/s |
| example | 42.0 |
| default value | |
| special processing | VALUE_REQUIRED |
| source | Science Data Processing (SDP) |
| software source | |
| calculation | jwst_dx value (geocentric) from either DefEphemeris or PredictEphemeris table where useAfter date is closest to the exposure's EXPMID time, converted into the barycentric frame. |
| DB destination | ['ScienceCommonExt.jwst_dx', 'GuideStarExt.jwst_dx'] |
| data type in DB | float |
| instrument | ALL |
| mode | All |
| product level | 1b |
| FITS hdu | SCI |
| FITS header section | Ephemeris |