The International Outer Planet Watch is a program for the encouragement and coordination of the study of temporal variations in the Outer Planets. The IOPW coordinates 24-hour coverage of outer planet phenomena when such coverage is needed. It provides a mechanism for the rapid sharing of information to the community of scientists studying the outer planets. The measurements it fosters provide a long term context for "snapshots" that in situ spacecraft, like Galileo and Cassini, provide. The program is built on the belief that cooperation achieves more than the random efforts of the same number of investigators; that much can be accomplished in the ground-based program especially in concert with a major in situ investigation; and that long term observations of the outer planets are essential to understanding their behavior. This program was originally founded as the International Jupiter Watch (IJW) to complement the Galileo program. A brief history of the IJW can be found in Russell et al. (1990) and in the preface to NASA SP-494,Time Variable Phenomena in the Jovian System (1989) .

The IOPW is coordinated by volunteer discipline working group leaders who are listed below. Oversight is provided by a steering committee presently chaired by Glenn Orton


a) Aurora, Magnetosphere and Io Torus
Note: In 2006 the IOPW combined the Io Torus, Magnetosphere and Radio Emission, and Aurora Discipline Working Groups into a single working group and divided them in 2012.

   Discipline Leader:
John T Clarke
Boston University
   Discipline Leader:
A. Steffl
(Magnetosphere and Io Torus)

b) Atmospheres

   Discipline Leader: Ricardo Hueso
Depto. Fisica Aplicada I
E.T.S. Ing. Industriales y Telecom
Alda. Urquijo s/n
48013 BILBAO (Spain)
Tel: (34) 946 014 262
Fax: (34) 946 014 178

c) Satellites

   Discipline Leader: Julie A. Rathbun
Department of Physics
University of Redlands
Redlands, CA 92373
Voice: 793-2121-8661

d) Laboratory & Theory

   Discipline Leader: Paul G Steffes
Electromagnetics and Telecommunications
Georgia Institute of Technology
Atlanta, Georgia 30332
Voice: 404-894-3128
Fax: 404-894-4641

e) Titan

   Discipline Leader: Henry G Roe
California Institute of Technology
Voice: 626-395-8708
Fax: 626-585-1917

f) Uranus and Neptune

   Discipline Leader: Mark Hofstadter
Jet Propulsion Laboratory
Pasadena, CA 91109
Fax: 818.393.4445

The IOPW Steering Committee

IOPW is overseen by a steering committee consisting of the Chair, Glenn Orton; permanent members: I. de Pater, D. M. Hunten, C. T.Russell, R. West, Heidi Hammel and a number of rotating members with 3 year terms.

Some Accomplishments

  • Early use of electronic newsletters
  • Coordination of observations of mutual occultations of Jovian satellites
  • Monitored rare large scale changes in Jovian atmosphere
  • Coordinated studies of atmospheric storms on Saturn
  • Provided alerts and exchanged information on the evolution of hotspots on Io
  • Assisted with the coordination of the Shoemaker - Levy impact observations
  • Provided supporting observations for the Galileo probe and orbiter missions

The chairman of the steering committee is Glenn Orton (

Minutes of Steering Committee Meetings

Other Relevant Websites Acknowledgments

We are grateful to the following individuals who have served as discipline group leaders over the course of the IJW/IOPW.

a) Io torus:
    N. Schneider
N. Thomas
M. McGrath
R. Oliversen
See i )
1986 - 1993
1993 - 1996
1997 - 2002
2002 - 2005
b) Jovian atmosphere:
    R. A. West
G. Orton
R. Beebe
A. Sanchez - Lavega
R. Hueso
1986 - 1989
1989 - 1996
1997 - 2001
2002 - 2009
2009 -
c) Satellites:
    W. Sinton
J. Goguen
J. Spencer
R. Howell
F. Marchis
J. Rathbun
1986 - 1990
1990 - 1993
1993 - 2000
2000 - 2003
2003 - 2012
2012 -
d) Magnetosphere/Radio Emissions:
    I. de Pater
M. Klein
S. Bolton
H. Rucker
P.H.M. Galopeau
See i )
1986 - 1994
1986 - 1994
1994 - 1997
1997 - 2001
2001 - 2005
e) Aurora:
    J. J. Caldwell
T. Kostiuk
R. Prange
J. Connerney
J. Clarke
1986 - 1990
1990 - 1994
1994 - 1997
1998 - 2006
2006 -
f) Laboratory:
    Barry Lutz
Kent Wells
J. Moses
K. Hibbits
1986 - 1993
1993 - 1995
1998 - 2004
2004 - 2005
2005 -
g) Titan:
    H. G. Roe
2004 -
h) Uranus and Neptune:
    H. Hammel
M. Hofstadter
2004 - 2012
2012 -
i) Magnetospheres and Io Torus:
    A. Steffl
2012 -

The following individuals have chaired the Steering Committee:

C. T. Russell 1986 - 1991
D. Morrison 1991 - 1993
D. Hunten 1993 - 2000
G. Orton 2000 -


Russell, C.T., et al., International Jupiter Watch: A Program to Study the Time Variability of the Jovian System , Adv. Space Res., Vol. 10, No. 1, (1)239-(1)242, 1990.

Updated: November 25,2015