Any application that uses precise timing, such as GPS navigation, will see an instant improvement in accuracy and reliability. Once these devices are deployed into our Master Clock system, we will be able to disseminate a reference time-scale some 10 to 50 times more precise than the current nanosecond/day requirement that we must meet for the Department of Defense. As for our timekeeping activities, we are now building six "rubidium fountain" atomic clocks.
#THE NAVAL OBSERVATORY FULL#
We will "mosaic" four of these chips together to cover a field of view that will extend over five degrees 25 times the area of the Full Moon and image 20th-magnitude stars with 100-second exposures. The UCAC "follow-on" will be done with the same instrument (or possibly a new telescope of 0.7-meter aperture) and a new detector, a custom-made 110 megapixel CCD. We are also expanding on the pioneering work of the UCAC. Using this data, we will be able to geometrically measure distances to stars within about 2 kiloparsecs (6,520 light-years) of Earth. We now have the technology to produce Hipparcos-precision astrometry for some 40 million stars. The European Space Agency's Hipparcos satellite made the first observations of this type, but the data are now well over a decade old and were limited to a few hundred thousand stars. What's coming next at the USNO? USNO is actively involved in pursuing a space-based astrometry program to obtain even more precision in star positions.
Astronomers will use these data to calibrate their telescopes, make high-precision observations of near-Earth asteroids and comets, and generally improve the precision of a variety of types of astronomical observations. When the final version is released we hope by the end of 2007 it will contain data on the positions and motions of more than 60 million stars, covering the entire celestial sphere. The UCAC is important because it is the deepest and most precise ground-based astrometric star catalog yet produced.
Then we relocated the survey to the USNO Flagstaff Station to complete the survey to the north celestial pole. USNO operated the astrograph at Cerro Tololo Inter-American Observatory in Chile from 1998 to 2001 to cover the southern sky. Each image covers a field of just over one square degree, or slightly more than 5 times the Full Moon's area. The CCD can detect magnitude 16 stars with a 100-second exposure. The UCAC astrograph boasts a custom lens that renders a flat image over a 4,096x4,096 pixel CCD. An astrograph is a telescope designed specially for astrophotography. The telescope is a Boller and Chivens 8-inch (20 centimeters) twin astrograph.
What is the USNO CCD Astrograph Catalog and why is it important? USNO CCD Astrograph Catalog (UCAC) is the first ground-based astrometric star catalog to cover the entire sky with the same telescope and detector.