About Earth Rotation Division
and Mizusawa Astrogeodynamics Observatory

Astronomy is making rapid progress in the light of increasing knowledge of the universe obtained by space techniques such as VLBI that enable us to explore more distant cosmic objects with higher spatial and temporal resolution and accuracy. Moreover, space techniques provide us geodetic tools to catch minute signals originated from various components of the Earth, the Moon and the planets, such as rotational variations, deformation, and gravity changes. Thus astronomy and Earth- planetary sciences are now in very close relation from both scientific and technological aspects.

We are promoting VERA Project, which will elucidate structure and dynamics of our Galaxy, and unmask nature and distribution of the Galactic dark matter by measuring 3-dimensional positions and motions of maser sources with a new domestic phase referencing VLBI array. We are also promoting RISE Project, which aims at clarifying the origin, internal structure, and evolution of the Moon by means of highly accurate measurements of the lunar gravity field and librations.

The Earth is considered to be an integrated system made up of various components including life, and is maintaining a delicate balance between environment and the life. Variations in the Earth's rotation, tidal and crustal deformations, and gravity changes are mirrors of temporal and spatial changes taking place in the Earth system, and therefore important targets of our research. Our recent research emphasis is put on studies of the dynamics of both the solid Earth and our Galaxy, by means of precise positioning with VLBI and GPS, as well as precise gravimetry with superconducting and absolute gravity meters.

Being a research institute designated as a Center of Excellence(COE), the National Astronomical Observatory (NAO) is playing various roles in astronomical sciences. To facilitate cooperative use by nationwide researchers, NAO has been developing and improving observational instruments, data analysis software, and other infrastructures as an inter- university research institute. NAO is also playing the role of the national center for international research cooperation. Also, NAO is contributing to education of graduate students in the framework of the Graduate University of Advanced Studies.