Gaia astrometric accuracy in the past

François Mignard (1)

1 CASSIOPEE - Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides

Gaia is due for launch in the third quarter of 2013 and will open a new page in fundamental astronomy. The astrometric accuracy achievable of about 20 muas/yr at G=15 to below 10 muas/yr at the bright end will permit to know the positions of millions stars with mas accuracy almost 100 years back in time. I will present the current expectations regarding the accuracy of Gaia astrometry at the end of the mission and explain how to propagate the stellar positions and their covariance matrix several decades away from the Gaia epoch without introducing modeling error. I will show also diagrams illustrating the positional accuracy down to 1900 as a function of magnitude and sky position.

Domaines: Planétologie et astrophysique de la terre [astro-ph.EP]; Planétologie et astrophysique de la terre [astro-ph.EP]

François Mignard. Gaia astrometric accuracy in the past. International Workshop NAROO-GAIA "A new reduction of old observations in the Gaia era", Paris Observatory, Jun 2012, Paris, France. pp. 77-82. ⟨hal-00758167⟩