calc_astrometric_error¶
- rubin_sim.phot_utils.calc_astrometric_error(mag, m5, fwhm_geom=0.7, nvisit=1, systematic_floor=10)¶
Calculate an expected astrometric error. Can be used to estimate this for general catalog purposes (use typical FWHM and n_visit=Number of visit). Or can be used for a single visit, use actual FWHM and n_visit=1.
- Parameters:
- mag: `float`
Magnitude of the source
- m5: `float`
Point source five sigma limiting magnitude of the image (or typical depth per image).
- fwhm_geom: `float`, optional
The geometric (physical) FWHM of the image, in arcseconds. Default 0.7.
- nvisit: `int`, optional
The number of visits/measurement. Default 1. If this is >1, the random error contribution is reduced by sqrt(nvisits).
- systematic_floor: `float`, optional
The systematic noise floor for the astrometric measurements, in mas. Default 10mas.
- Returns:
- astrom_err
float
Astrometric error for a given SNR, in mas.
- astrom_err