Sub-group on the Densification of the Optical Frame
Newsletter 5
January 12, 2000
Dear Colleagues,
This is the fifth newsletter of the Sub-group on the Densification
of the Optical Reference Frame.
Quite a bit of work has taken place over the last several months.
The "Projects" page under the WG website has been recently updated.
However, there are a few items I would like to highlight.
1) IAU Colloquium 180 and preparations for the IAU GA
IAU Colloquium 180, titled "Towards Models and Constants for
Sub-Microarcsecond Astrometry" will be held in Washington, DC in
late March. For further information, see the website at
'http://aa.usno.navy.mil/colloq180/'.
As part of this colloquium, F. Mignard will be presenting work
done by the various ICRS sub-groups over the last three years.
If there is any work that has NOT been reported in these newsletters
that you wish him to include, please contact me.
One purpose of Colloquium 180 will be to draft any resolutions
that are desired. I am polling the members of this subgroup
concerning this topic. Please respond to the questions at the
end of this newsletter by February 24.
2) FAME selected by NASA for a 2004 launch
FAME, an astrometric satellite in the style of Hipparcos, has been
selected by NASA for launch in mid-2004. Projected accuracies
are 50 uas, 50 uas, and 50 uas/yr for position, parallax, and proper
motion respectively for stars brighter than about V=10. Errors are
magnitude dependent, and increase by about an order of magnitude
at V=15. FAME is designed to observe 40 million stars. In addition
to the astrometry, 4 color photometry is also planned.
3) Tycho-2 to be released February 2000
The Tycho-2 catalogue will be publicly available beginning
February 9, 2000. A mass mailing of CD-ROMs is planned. Those who
have received the Hipparcos set or the ACT CD-ROM should
be receiving the Tycho-2 disk in the mail around the end of February.
For additional details, see the "Projects" page under the WG website.
4) UCAC Preliminary catalog near completion
The UCAC1, a first version of the USNO CCD Astrograph Catalog is
scheduled to be released by the end of January 2000. The catalog
contains precise positions and preliminary proper motions of about
27 million stars, covering most of the Southern Hemisphere.
The positions are based on new observations taken with the USNO
8-inch astrograph at the Cerro Tololo Inter-American Observatory (CTIO)
between February 1998 and November 1999. For stars in the
magnitude range of 9 to 14 the precision is about 20 mas.
The limiting magnitude is about 16 with an estimated standard error of
70 mas per position coordinate at the faint end. The system is
Hipparcos/ICRF. For additional details, see the "Projects" page
under the WG website.
5) 2MASS ready for next release
The 2MASS project is well under way, and the second incremental
release is scheduled for early 2000. For additional details,
follow the links under the "Projects" page of the WG website.
As always, I am open to suggestions about the website, including
posting news on other projects which may be important to the group.
Sincerely,
Sean Urban
U.S. Naval Observatory
January 12, 2000
http://ad.usno.navy.mil/ad/dens_wg/dens.html
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Questions concerning the need for any resolutions affecting the
densification of the optical reference frame.
- Your name
- Are any resolutions concerning the densification of the optical
reference frame needed at this time?
- If yes, describe what is needed and what problems the resolution
is trying to solve.
Please return this to me no later than February 24, 2000
seu@pyxis.usno.navy.mil
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