position_uncertainty

pygaia.errors.astrometric.position_uncertainty(gmag, release='dr4')

Calculate the sky averaged position uncertainties from G, for a given Gaia data release.

Parameters:

• gmag (float or array) – Value(s) of G-band magnitude.

• release (str) – Specify the Gaia data release for which the performance is to be simulated. ‘dr3’ -> Gaia (E)DR3, ‘dr4’ -> Gaia DR4, ‘dr5’ -> Gaia DR5. Default is ‘dr4’.

Returns:

ra_cosdelta_uncertainty, delta_uncertainty – The uncertainty in alpha* and the uncertainty in delta, in that order, in micro-arcseconds.

Return type:

float or array

Raises:

ValueError – When an invalid string is specified for the release parameter.

Notes

The uncertainties are for sky positions in the ICRS (i.e., right ascension, declination). Make sure your simulated astrometry is also on the ICRS.