The IAU Symposium 248 brought together new results from the Hipparcos catalogue and several studies related to the upcoming Gaia mission, as well as ground-based projects such as LSST at optical, ALMA at microwave and SKA at radio frequencies. Also covered were specific and theoretical developments concerning the ICRS, the ICRF and the New Conventional Origin. Added to all these most varied and far-reaching astrometric advances, the crucial point of the symposium rational was to assemble astronomers with diverse expertise and to attract young people to the field.

The symposium had nine sessions, namely,

1. Hipparcos Catalogue,
2. Highlights of Optical Astrometry,
3. Astrometry with Radio Interferometers,
4. Space Astrometry: Status and Future,
5. Celestial Reference Frames,
6. Towards Reference Frame at the Micro-arcsecond Level,
7. Stellar Parameters and Galactic Structure & Evolution,
8. Astrometric Education,
9. Astrometry in the Age of Large Surveys and Virtual Observatories.

There were presented 32 invited presentations, 30 oral communications, 122 posters, a round table discussion on education and an open discussion held at the end of the meeting.

The Hipparcos Catalogue session presented highlights from the mission in various domains of astronomy, especially towards stellar and galactic studies. In the following session, Highlights of Optical Astrometry, a re-reduction of the Hipparcos raw data was presented. Also presented were applications on brown dwarfs, binaries, the galactic center, as well as solar system bodies. Several projects were reviewed in the Astrometry with Radio Interferometers session: the VLBA and VLBI networks, the VERA, ALMA, and Square Kilometer arrays and the FAST single dish. The Space Astrometry Status and Future session discussed in depth the projects Gaia, SIM and JASMINE, as well as planned optical space interferometry missions such as TPF/Darwin, SIM and MAXIM. The Celestial Reference Frame session has shown the progress on the maintenance of all-sky catalogues such as the USNO-B, the GSC2.3 and the UCAC2. Also infrared catalogues and the dedicated field Deep Astrometric Standards project were covered. To complement this, the Towards Reference Frame at the Micro-arcsecond Level session dwelt on improvements upon the ICRF and theoretical advances from relativistic astrometry and the celestial intermediate reference frame. The next session, Stellar Parameters and Galactic Structure & Evolution, brought several applications of astrometric techniques to astrophysical questions, such as stellar metallicity, galactic structure and planet formation. The Astrometric Education session, emphasized both the teaching and desirable curricula for astrometry in addition to the broadness of application as key factors for the next generation of astrometrists. On this note, the last session Astrometry in the Age of Large Surveys and Virtual Observatories underlined the central role played by the astrometric techniques on holding together large, synoptic projects such as the SDSS, the VO, DENIS, Pan-STARRS, and LAMOST.

The final open discussion and closing remarks stressed the many state-of-the-art investigations, which will be present in the forthcoming symposium volume (ISBN-10: 052187470X), that result in milli- to micro- arcsecond precision astrometry across the spectral domain from radio observations to the infrared and optical regions, up to the UV and X-ray extremes. The combination of the vigorous advance of astrometric techniques and their increasing utilization on many broad astronomical subjects, make ever more up-to-date the final quotation: "By carefully watching the position of the celestial objects on the sky over the course of time you can find out (almost) all there is to know about the universe".

Parameter Space Coverage: The number of surveyed objects is indicated by the right column. (from Anthony Brown's "Closing Remarks")

The symposium in its concluding resolution issued, through the SOC, an endorsement of the activities and funding merit on four major areas of astrometry, of particular interest for the modeling and astrophysical interpretation of advanced milli- to micro- arcsecond astrometric data.

Presentations and photos from the meeting are available to download.