AIM OF THE WG

FDGBA was founded in 2000, during the XXIVth General Assembly in Manchester, UK, as working group of the Division 1.
It appeared as a consequence of the new state of astrometry after the success of Hipparcos mission.

As the Newsletter No.1 of the IAU Commission 8 announced, "The post-Hipparcos era has brought an element of uncertainty as to the goals and future programs for all of ground-based astrometry". The WG had as main objective to identify such programs and make assessment of the whole situation including available instrumentation. It has "to identify scientifically important programs that can be realized using ground-based astrometric or related observations, and to study what kind of modifications, upgrades or additions to the existing instruments should be performed in order to provide useful astronomical information with necessary accuracy, keeping in mind what the future astrometric satellites will contribute. "

A final objective that we see for this working group is to identify programs that could be made on instruments that are either insufficiently used or working on projects that have no significant value for the present day astrometry. A major reason for this is that these instruments can be used as they are or with not too expensive modifications to teach students in astronomy how to use telescopes and in the same time to contribute in a significant way to astronomy.

The WG organised two international meeting (Munich 2001, Bucharest 2003), a third one being held just during the XXV IAU GA, at Sydney, on 21 July, 16h00-17h30, after a report was presented on July 17, during the Scientific meeting of Division 1, 14h00-15h30 (see the attached report, edited by its chairs Jean Kovalevsky and Magda Stavinschi).

Following a questionnaire spread to its members, a proposal for continuing for other three years was presented at the IAU GA.

As arguments, we could mention:

There were 3 planned astrometric satellites: FAME, DIVA, and GAIA, but only GAIA will be launched but not earlier as 6 years. So, for the next decade there is no future for space astrometry. In the mean time, astronomers are abandoning astrometric observing projects. For example, USNO is dismantling its solar system astrometric observing program.

But, there still are some programmes, which could be done, before the astrometric space missions, preparing them, and even later.
- astrometric observations of some natural satellites, asteroids and comets with small or medium-sized telescopes
- monitoring selected asteroids approaching the Earth
- observations of artificial objects and space events and other natural phenomena generating hazards in the vicinity of the Earth
- improving double star orbits
- astrometric re-reduction of old observations of bright main belt asteroids obtained at Golosiiv in the system of modern catalogues such as Tycho-2 to improve asteroid orbits
- astrometric observations of the areas around extragalactic radiosources to extend Hipparcos system to the faint stars
- rediscovering of recently discovered asteroids with the help of digital plate archive that we are creating now as a part of the work on the integration of our plate archive into national and international virtual observatories.

FDGBA couldn't be abandoned before a possible space mission should do it with higher accuracy. And if the G-B observations would continue to be done it should be very convenient a WG to unify criteria, coordinate jobs among different institutions and to promote meetings between people working in this field, to organize summer schools for the young astrometrists.

The IAU Division 1 approved the prolongation of its activity until the next GA (Prague, 2006) when it will become part of the Commission "Astrometry."