`doppler_shift`¶

Doppler-shift the wavelength axis by a radial velocity.


Category	Corrections
Backend	`astropy` - wraps the domain-standard astropy implementation
Version	`1.0.0`
Reads	`ctx.spectrum` (a `Spectrum1D`)
Writes	`spectrum`, `metrics.applied_velocity_kms`

Parameters¶

Parameter	Default	Required	Description
`velocity_kms`	`None`	yes	Radial velocity in km/s (positive = redshift).

PythonCLIMCP

from spectro_kernel import run_algorithm

output = run_algorithm("doppler_shift", ctx, {
    "velocity_kms": "<value>"
})

spectro run doppler_shift --input spectrum.fits \
  --param velocity_kms=<value>

{
  "tool": "doppler_shift",
  "arguments": {
    "session_id": "<session_id>",
    "params": {
      "velocity_kms": "<value>"
    }
  }
}

Every algorithm is an MCP tool of the same name; describe_algorithm returns this page's metadata as JSON.

air_to_vacuum - Convert the wavelength axis from air to vacuum wavelengths.
barycentric_correction - Compute the barycentric (or heliocentric) correction and Julian date, and shift the spectrum.
extinction_correct_easyspec - Apply atmospheric extinction correction to ctx.spectrum via easyspec.
fit_telluric_scaling - Fit the airmass that best matches a telluric template to ctx.spectrum.
remove_telluric_division - Remove telluric absorption by dividing the science spectrum by a reference.
synth_telluric - Generate a synthetic telluric transmission spectrum.
vacuum_to_air - Convert the wavelength axis from vacuum to air wavelengths.