The SRG orbit files are offered for users who want to perform barycentric corrections to SRG/eROSITA event files. The files are provided in FITS format and were converted to FITS from ASCII files provided by NPOL.
Three orbit files are available. Each file covers one calender month
(October,
November,
December) of EDR. The files are named: srg_orbit_<yyyy><mm>.fits.gz.
This README file gives an example how to use these orbit files with the HEASOFT barycen task.
The orbit data are contained in the FITS extension ORBIT.
Description of table columns:
| Name | Type | Unit | Description |
|---|---|---|---|
| DATE | string | s | UTC date |
| UTC | string | deg | UTC time |
| MJD | double | d | Modified Julian Date (TT) |
| TIME | double | s | SRG/eROSITA spacecraft time |
| X | double | m | geocentric X position (J2000) |
| Y | double | m | geocentric Y position (J2000) |
| Z | double | m | geocentric Y position (J2000) |
| VX | double | m/s | velocity in X direction |
| VY | double | m/s | velocity in Y direction |
| VZ | double | m/s | velocity in Z direction |