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GALAH+ is a magnitude-limited survey of high resolution stellar spectraobtained by the HERMES spectrograph at the Australian Astronomical Observatory.Its third data release provides reduced spectra with new derivations of stellarparameters and abundances of 30 chemical elements for 584,015 dwarfs andgiants, 88% of them in the Gaia magnitude range 11 < G < 14. Here we use theseimproved values of stellar parameters to build a library of observed spectrawhich is useful to study variations of individual spectral lines with stellarparameters. This and other improvements are used to derive radial velocitieswith uncertainties which are generally within 0.1 km/s or ~25% smaller than inthe previous release. Median differences in radial velocities measured here andby the Gaia DR2 or APOGEE DR16 surveys are smaller than 30 m/s, a larger offsetis present only for Gaia measurements of giant stars. We identify 4483 starswith intrinsically variable velocities and 225 stars for which the velocitystays constant over >=3 visits spanning more than a year. The combination ofradial velocities from GALAH+ with distances and sky plane motions from Gaiaenables studies of dynamics within streams and clusters. For example, weestimate that the open cluster M67 has a total mass of ~3300 Msun and its outerparts seem to be expanding, though astrometry with a larger time-span thancurrently available from Gaia eDR3 is needed to judge if the latter result isreal.

The GALAH+ Survey: A New Library of Observed Stellar Spectra Improves Radial Velocities and Hints at Motions within M67