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We present a pilot study of Galactic globular cluster (GC) proper motion (PM)determinations using Gaia data. We search for GC stars in the Tycho-GaiaAstrometric Solution (TGAS) catalogue from Gaia Data Release 1 (DR1), andidentify five members of NGC104 (47 Tucanae), one member of NGC5272 (M3), fivemembers of NGC6121 (M4), seven members of NGC6397, and two members of NGC6656(M22). By taking a weighted average of member stars, fully accounting for thecorrelations between parameters, we estimate the parallax (and, hence,distance) and PM of the GCs. This provides a homogeneous PM study of multipleGCs based on an astrometric catalog with small and well-controlled systematicerrors, and yields random PM errors similar to existing measurements. Detailedcomparison to the available Hubble Space Telescope (HST) measurements generallyshows excellent agreement, validating the astrometric quality of both TGAS andHST. By contrast, comparison to ground-based measurements shows that some ofthose must have systematic errors exceeding the random errors. Our parallaxestimates have uncertainties an order of magnitude larger than previousstudies, but nevertheless imply distances consistent with previous estimates.By combining our PM measurements with literature positions, distances, andradial velocities, we measure Galactocentric space motions for the clusters andfind that these also agree well with previous analyses. Our analysis provides aframework for determining more accurate distances and PMs of Galactic GCs usingfuture Gaia data releases. This will provide crucial constraints on the nearend of the cosmic distance ladder and provide accurate GC orbital histories.

Tycho-Gaia Astrometric Solution Parallaxes and Proper Motions for Five Galactic Globular Clusters