total_position_uncertainty

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

Calculate the sky averaged total position uncertainty as a function of G and for the given Gaia data release. This refers to the semi-major axis of the position error ellipse.

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:

The semi-major axis of the position error ellipse in micro-arcseconds.

Return type:

position_uncertainty

Raises:

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

Notes

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