EPRV Standard Units & Reference Frames

The EPRV data standard adopts the following units and reference frames for all data products

Parameter	Unit / Reference Frame	Comment
Wavelength Solution	in vacuum
Barycentric Correction	solar barycenter rest frame	does not include the systemic velocity
Wavelength Units	Angstrom or Micron	We recommend following the FITS standard by using one of its standard units. Define bitdepth to be 64 bit
Flux Units	Photoelectrons
Time Units	BJD_TDB and UTC.
Exposure time	Seconds
SNR Units	SNR per pixel	use EXSNRW header keyword to specify SNR wavelength
RA/Dec Coordinates	Sexigesimal
Epoch	Native epoch of the survey	e.g. 2015.5 for Gaia DR2
Proper Motions	milliarcsecond/year
Color	Gaia Bp - Rp	Unless otherwise specified in header keywords
Systemic Velocity	km/s
CCF Velocity	km/s
RV Measurement	km/s