Y component of the JWST velocity vector at the mid-point of the exposure in the ECI-J2000 coordinate frame, which is an Earth-centered inertial frame defined by the Earth's mean equator and equinox on 2000-Jan-01. Science Data Processing code (SDP) reads this from the observatory ephemeris data.
| Attribute | Value |
|---|---|
| data type | float |
| enumerated Values | not defined |
| units | km/s |
| example | 42.0 |
| default value | |
| special processing | VALUE_REQUIRED |
| source | Ephemeris |
| software source | |
| calculation | Value from either DefinitiveEphemeris or PredictedEphemeris tables where useAfter date is closest to the exposure's EXPMID time. |
| DB destination | ['ScienceCommon.jwst_dy', 'GuideStar.jwst_dy'] |
| data type in DB | float |
| instrument | Multiple |
| mode | All |
| product level | 1b |
| FITS hdu | PRIMARY |
| FITS header section | Exphemeris |