![[IAU logo here]](IAUlogomed.gif)
International Astronomical UnionCommission 4 : Ephemerides Newsletter Nr. 9 |
International Astronomical UnionCommission 4 : Ephemerides Newsletter Nr. 9 |
September 29, 1999
Subject: Newsletter No. 9
International Astronomical Union
Commission 4: Ephemerides
Newsletter No. 9 September 29, 1999
---------------------------------------------------------------------------
President Vice President
E Myles Standish Jr Jean Chapront
301-150 Bureau des Longitudes
Jet Propulsion Laboratory 77, avenue Denfert Rochereau
Pasadena, CA 91109 USA F-75014 Paris, FRANCE
Tel: 1 818 354 3959 Tel: 33
Fax: 1 818 393 6388 Fax:
ems@smyles.jpl.nasa.gov jean.chapront@bdl.fr
---------------------------------------------------------------------------
9.0 Contents of this Newsletter
9.1 First Announcement of IAU Colloquium 180
---------------------------------------------------------------------------
9.1
FIRST ANNOUNCEMENT 15 Sept 1999
International Astronomical Union
International Earth Rotation Service
U.S. Naval Observatory
TOWARDS MODELS AND CONSTANTS FOR SUB-MICROARCSECOND ASTROMETRY
IAU Colloquium 180
27-31 March 2000
U.S. Naval Observatory, Washington, DC, USA
http://aa.usno.navy.mil/colloq180/
ANNOUNCEMENT
The adoption of the International Celestial Reference System
(ICRS) by the XXIII General Assembly of the IAU provides an
improved reference system for positional astronomy. However,
the specifications of the ICRS remain incomplete for Earth-based
observing systems because the system cannot be accurately
propagated to arbitrary epochs using currently adopted algorithms
for Earth orientation. Current models for precession and
nutation, specified by the IAU in the early 1980s, are now known
to have deficiencies that are significant for many modern
applications, such as ground-based interferometry. Moreover,
a new set of values of fundamental astronomical constants
(parameters) is needed consistent with ICRS accuracy and
expressed in units that are properly specified, in a relativistic
sense, in the barycentric and geocentric reference systems
defined by previous IAU resolutions. Procedures for dealing with
the small offsets of the ICRS from the system defined by the
kinematics of Earth rotation must also be specified for those
observations sensitive to it. Furthermore, the needed change
in the precession/nutation model will require reconsideration of
the definition of Universal Time.
The reports of the IAU Working Groups addressing these issues
will be presented and discussed. The major purpose of the
colloquium is to prepare resolutions for consideration by a Joint
Discussion at the XXIV IAU General Assembly that will complete
the specification of the ICRS. These resolutions will, in
effect, specify definitions, standard algorithms, and parameters
that link observable quantities with reference coordinates within
the ICRS system. Specifically to be recommended are definitions
of the celestial ephemeris pole and celestial ephemeris origin,
an improved precession/nutation theory, and a new set of standard
values for astronomical constants.
This colloquium will also discuss future requirements of the
celestial reference system that are necessary to support present
and planned high-precision astrometric programs. These programs
include ground-based observations currently made in the optical,
IR, and radio regimes using both single-aperture telescopes and
interferometers. Future proposed space missions using or
providing accurate astrometry include DIVA, FAME, SIM, Darwin,
NGST, Terrestrial Planet Finder, and GAIA. The
microarcsecond-level of precision anticipated for future
observational systems demands improved models at all levels of
analysis. These improved models are likely to require increased
attention to the definitions of the various reference frames
involved and the transformations between them, within the
relativistic framework previously established by the IAU. The
specification of new models and constants will also contribute to
many other aspects of astronomy, astrophysics, geodesy,
geophysics, space navigation, and timing.
In order to accomplish its goals, the colloquium will be
organized in a workshop format, with both formal presentations
and discussion sessions. Arrangements will be made for meetings
of the relevant IAU Working Groups if needed.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
ORGANIZATION
This meeting is sponsored by the International Astronomical
Union (IAU) and the International Earth Orientation
Service (IERS). Supporting IAU Commissions include 4, 8, 19,
24, 31, and 40.
SCIENTIFIC ORGANIZING COMMITTEE: Kenneth Johnston (chair),
Victor A. Brumberg, Nicole Capitaine, Veronique Dehant,
Toshio Fukushima, Wenjing Jin, Jean Kovalevsky, Dennis McCarthy,
Francois Mignard, Gerard Petit, P. Kenneth Seidelmann,
Michael Soffel, E. Myles Standish, Jan Vondrak.
LOCAL ORGANIZING COMMITTEE: George Kaplan (chair),
F. Stephen Gauss, Brian Luzum, Chopo Ma, Nancy Oliversen,
Lynn Treadway, Sean Urban.
PROCEEDINGS EDITORS: Kenneth Johnston, Dennis McCarthy,
George Kaplan.
WEB SITE: http://aa.usno.navy.mil/colloq180/
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
PRELIMINARY PROGRAM
Celestial Reference Systems and Frames
Celestial Reference Systems - Overview
Report of the IAU Working Group on the International
Celestial Reference System
Celestial Reference Frame Realizations at Various
Wavelengths - Present Status and Future Possibilities:
Radio, Optical, Infrared, UV, X-Ray, etc.
Limitations on the Accuracy of Celestial Reference Frames -
Source Structure, Binary Stars, Microlensing,
Interstellar/Intergalactic/Interplanetary Medium Effects,
Earth's Atmosphere, Terrestrial Reference Frame
Dynamical Reference Frame - Current Relevance and Future
Prospects
Definition of the Celestial Ephemeris Pole and the Celestial
Ephemeris Origin
Summary/Resolution
Relativistic Considerations for High Precision Dynamical
Astronomy
Relativity and Astronomy - Overview
Report of the Working Group on General Relativity for
Space-Time Reference Systems and Metrology
Report of the Working Group on Relativity for Celestial
Mechanics and Astrometry
Summary/Resolution
Precession and Nutation
Report of the IAU Working Group on Non-Rigid Earth Nutation
Theory
VLBI Observations
Rigid-Earth Nutation Models
Improved Models for Precession and Nutation
Sub-Diurnal Effects
Summary/Resolution
Time and Constants
Time and Standards - Overview
Report of the Working Group on Astronomical Standards
Report of IAG Special Commission 3 on Parameters
Report on SOFA
Future Coordinated Universal Time
Summary/Resolution
Discussion of Resolutions for the IAU General Assembly
Definition of the Celestial Ephemeris Pole and Celestial
Ephemeris Origin, Relativity, Constants (Parameters),
Time, Precession/Nutation, Others as Needed
Discussion of Resolutions
Requirements for Improved Accuracy in Celestial Reference
Systems
Ground-Based Observations
Optical Interferometry
Radio
IR
Space Missions
FAME
SIM
GAIA
Relativistic Timescales for Sub-Microarcsecond Astrometry
Distance Scales, Stellar and Galactic Dynamics
Searches for Planetary Systems
IERS, Geophysics, Geodesy
Adoption of Resolutions for the IAU General Assembly
Summary
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
CALL FOR PAPERS
Because of the workshop nature of this colloquium, only invited
papers will be oral.
Papers directly relevant to the topics of the colloquium are
solicited from attendees. All contributed papers will be poster
papers. It is hoped that multiple poster sessions will not be
needed, and that poster papers can remain in place the entire
week of the colloquium.
Paper abstracts should be submitted online via the colloquium
web site. The deadline for abstract submissions is 15 Jan
(15 Nov for those requesting financial assistance; see below).
At least one author of each paper must be a colloquium
participant. A point of contact must be designated for each
paper (one of the authors who will be attending the colloquium),
who will be notified of paper acceptance within two weeks
of submission.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
LOGISTICAL INFORMATION
LOCATION OF COLLOQUIUM:
Both oral and poster sessions will be held in building 56 of the
U.S. Naval Observatory in Washington, DC. This is a recently
renovated building with a new conference room, probably not
familiar to most conference participants. Rooms for working
group meetings will be made available if needed.
REGISTRATION:
Registration procedures for the colloquium itself have not yet
been established. The registration fee will be approximately
$200 US. We hope to be able to offer online or fax registration
with credit card payment of the registration fee. For those
unable to register this way, paper mail registration will be
accepted if accompanied by an international money order,
traveler's check, or personal check drawn on a US bank (in US
dollars only). We will not be able to accept institutional
purchase orders. PLEASE DO NOT ATTEMPT TO REGISTER FOR THE
COLLOQUIUM NOW. Registration procedures will be posted on the
web site when available.
HOTEL RESERVATIONS:
Blocks of hotel rooms have been reserved for colloquium attendees
at two hotels within walking distance of the Naval Observatory,
the Holiday Inn and the Savoy Suites. Room rates in the reserved
blocks range from $115 to $149 (plus tax). Hotel rooms can be
reserved now -- see colloquium web site for details. Hotel
reservations are separate from colloquium registration and are
the responsibility of the individual participant. Rooms in the
blocks reserved for the colloquium must be booked by 11 Feb for
the Holiday Inn and 18 Feb for the Savoy Suites. Information on
other nearby hotels is also given on the web pages.
RECEPTION AND BANQUET:
A reception at the Naval Observatory is being arranged for early
in the week, and a banquet at one of the hotels for later in the
week. Both events will be covered by the registration fee.
Guests will be welcome at the reception, and guest tickets for
the banquet will be available at cost (approximately $40).
FINANCIAL ASSISTANCE:
A limited amount of financial assistance will be available.
Requests for such assistance should be sent to Dr. Kenneth
Johnston, Chair of the Colloquium 180 Scientific Organizing
Committee, at e-mail address johnston.kenneth@usno.navy.mil or at
postal address
Dr. Kenneth Johnston
Chair, Colloquium 180 SOC
U.S. Naval Observatory
3450 Massachusetts Avenue NW
Washington, DC 20392-5420
USA
The deadline for consideration for financial assistance is 15
Nov. Those requesting financial assistance must have submitted
abstracts for any contributed papers by this date.
FURTHER INFORMATION:
Further information will be posted at the colloquium's web site,
http://aa.usno.navy.mil/colloq180/, as it becomes available.
We hope to see as many of our colleagues as possible at this
important meeting.
Kenneth J. Johnston
Chair, IAU Colloquium 180
Scientific Organizing Committee
johnston.kenneth@usno.navy.mil
George H. Kaplan
Chair, IAU Colloquium 180
Local Organizing Committee
gkaplan@usno.navy.mil
--------------------------------------------------------------------------
Myles Standish