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	Gazette IERS Gazette IERS Gazette IERS Gazette IERS Gazette 
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	No 31, 4 April 1998       /
_________________________________/                Contact: iers@obspm.fr
                                     ftp:  hpiers.obspm.fr (145.238.100.28)
                              WWW:  http://hpiers.obspm.fr
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        Author: Alan Fey (U.S. Naval Observatory)
        Subject: Northern Hemisphere Radio Sources Imaged

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Dear colleagues,

A milestone was reached this month  with the completion of first epoch
imaging of northern hemisphere radio  reference frame sources.  Images
at both S-  and X-band now exist  for  approximately 97% of  the Radio
Optical Reference  Frame (Johnston  et  al.  1995,AJ,110,880)  sources
north  of minus   20 degrees  declination  [approximately  90% of  the
International  Celestial Reference  Frame sources  north  of minus  20
degrees declination].

The USNO Radio Reference Frame Image Database now contains 1413 images
of 411 sources at radio frequencies of  2-, 8-, and 15-GHz. The images
are available for scientific use by anyone and can be accessed via the
World Wide Web at the URL:

            http://maia.usno.navy.mil/rorf/rrfid.html
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