000007508 001__ 7508
000007508 005__ 20250204105204.0
000007508 037__ $$aCTALK-2025-0062
000007508 100__ $$aIvantsov, Anatoliy
000007508 245__ $$aAstrometric bias caused by inhomogeneous background
000007508 260__ $$c2024
000007508 269__ $$c2024-08-14
000007508 520__ $$aAll kinds of measurements are taken against some background. The greater the signal-to-noise ratio is, the smaller error is expected in both position and magnitude of an object. If we take measurements of the objects that are slightly less than the magnitude of the background, their positions will be affected by background inhomogeneity. In the case of point sources with the Gaussian-like distribution of intensity, the symmetry is broken, and the source's position is biased. We provide an analytic solution for the bias of the Gaussian image if the neighbourhood background gradient is known or measured. The solution explains the exponential-looking degradation of the astrometric errors with respect to the magnitude and gives a way to balance the reduction by the proper weights introduced. The abstraction allows correcting the bias in the astrometry of Gaussian-like sources whatever wavelengths or instruments are used.
000007508 594__ $$aNO
000007508 6531_ $$aastrometry,
000007508 6531_ $$abias,
000007508 6531_ $$asystematic error,
000007508 6531_ $$abackground gradient,
000007508 6531_ $$aGaussian image
000007508 773__ $$tXXXII IAU General Assembly Focus Meeting 11 Multi-wavelength Astrometry
000007508 8560_ $$fanatoliy.ivantsov@ksb-orb.be
000007508 85642 $$ahttps://zenodo.org/records/13785110
000007508 8564_ $$s2516915$$uhttp://publi2-as.oma.be/record/7508/files/ivantsov_fm11_2024.pdf
000007508 8564_ $$s10169$$uhttp://publi2-as.oma.be/record/7508/files/ivantsov_fm11_2024.jpg?subformat=icon-180$$xicon-180
000007508 8564_ $$s8176$$uhttp://publi2-as.oma.be/record/7508/files/ivantsov_fm11_2024.gif?subformat=icon$$xicon
000007508 906__ $$aContributed
000007508 980__ $$aCTALKCONT