The Radial Velocity Experiment (RAVE) has made data from the first year of operations publicly available. The data set, available to download from the RAVE website, consists of the new line-of-sight motions for some 25,000 stars, plus data on their brightness, colour and motion across the sky.
RAVE is a spectroscopic survey that aims to measure the radial velocities and stellar atmosphere parameters (temperature, metallicity, surface gravity) of up to one million stars near the Sun. The survey uses the 'six degree field' (6dF) multi-object spectrograph on the 1.2-m UK Schmidt Telescope of the Anglo-Australian Observatory (AAO), sited at Siding Spring Observatory in New South Wales, Australia. This instrument is capable of obtaining spectroscopic information for as many as 150 stars at once, over a full six degree diameter - a hundred times larger than most current spectrographs can handle.
In addition to providing a valuable data set for studying many aspects of galactic evolution, this large data base of stellar spectra will provide a useful training set for the development of the processing software and scientific analysis of spectra (for the brightest 100-150 million stars) acquired by the Radial Velocity Spectrometer instrument on Gaia.
The image above shows a map of the Milky Way from Lund Observatory, overlaid with the fields observed for RAVE's first data release. Each blue circle is a patch of sky six degrees across - the field of view of the Anglo-Australian Observatory's UK Schmidt telescope. The red line marks the boundary between the southern and northern equatorial hemispheres.
Image credit: Richard Sword, George Seabroke (Cambridge) and the RAVE collaboration. Milky Way image copyright Lund Observatory.