cwitools.reduction.units.heliocentric

cwitools.reduction.units.heliocentric(fits_in, mask=False, return_vcorr=False, resample=True, vcorr=None, barycentric=False)

Apply heliocentric correction to the cubes. Note that this only works for KCWI data because the location of the Keck Observatory is hard-coded in the function.

Parameters:
  • fits_in (astropy HDU / HDUList) – Input HDU/HDUList with 3D data.
  • mask (bool) – Set if the cube is a mask cube. This only works for resampled cubes.
  • return_vcorr (bool) – If set, return the correction velocity (in km/s) as well.
  • resample (bool) – Resample the cube to the original wavelength grid?
  • vcorr (float) – Use a different correction velocity.
  • barycentric (bool) – Use barycentric correction instead of heliocentric.
Returns:

Trimmed FITS object with updated header. vcorr (float): (if vcorr is True) Correction velocity in km/s. *Return type matches type of fits_in argument.
Return type:

HDU / HDUList*

Examples

To apply heliocentric correction,

>>> hdu_new = heliocentric(hdu_old)

However, this resamples the wavelengths back to the original grid. To use the new grid without resampling the data,

>>> hdu_new = heliocentric(hdu_old, resample=False)