Gaia on-board metrology: basic angle and best focus

• The Gala payload ensures maximum passive stability using a single material, SiC, for most of its elements. Dedicated metrology instruments are, however, required to carry out two functions: monitoring the basic angle and refocusing the telescope. Two interferometers fed by the same laser are used to measure the basic angle changes at the level of pas (prad, micropixel), which is the highest level ever achieved in space. Two ShackHartmann wavefront sensors, combined with an ad-hoc analysis of the scientific data are used to define and reach the overall best-focus. In this contribution, the systems, data analysis, procedures and performance achieved during commissioning are presented

Ämnesord

NATURVETENSKAP  -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)

Nyckelord

Astrometry

Gaia

metrology

interferometry

basic angle monitor

wavefront sensor

Shack-Hartmann

wavefront reconstruction

centroid

Cramer-Rao

spectral resolution

Publikations- och innehållstyp

kon (ämneskategori)

ref (ämneskategori)