The launch of Gaia in 2013 December ushered in a new era of space astrometry. allowing for fundamental reference research at an unprecedented level of precision. The international celestial reference frames in the radio band and the Gaia celestial reference frame in the optical band have been established and are consistent within several microarcseconds for axes orientation. To bridge... https://lecoureures.shop/product-category/ski-de-fond-enfant-fixations-classic/