Announcement of the Full Public Availability of All Yohkoh Data

2001 March 1

A new decision has been made in the international Yohkoh team that all the Yohkoh data be immediately opened to the world science community without any delay except for a short time for reformatting the data. This new will become effective when this announcement is For more than nine years since launch on 30 August 1991, the Yohkoh has opened a full set of data, together with a software package for analysis, after one year had elapsed since acquisition. The one-year for privileged data use by Yohkoh team members was introduced as a to those who worked hard for instruments buildings as well as to those contribute to daily satellite operations by sacrificing their own time to do science. On the other hand, the one-year interval might not be ideal for the quickest and widest data use by the world science community.

Evaluating such positive and negative aspects, we have reached a consensus that the reasoning for holding the privileged data use interval is now drastically reduced thanks to longevity of Yohkoh. Thus, with concurrence by ISAS, we here announce a new policy that all the Yohkoh data be immediately after acquisition. We hope the world science community in solar physics and physics will analyze Yohkoh data as actively as but more quickly before. Those who are not familiar with how to make use of the Yohkoh data, please contact:

Takeo Kosugi, ISAS, representing Japanese participation

Loren Acton, Montana St. Univ., representing US participation

J. Len Culhane, MSSL, representing UK participation

Original Announcement of the Public Release of the Yohkoh Data Archive

1993 September

It is our greatest pleasure to announce that the data from the first twelve months of operation of the scientific instruments of the Yohkoh Mission are now available for scientific and educational uses. that the data from the first twelve months of operation of the scientific instruments of the Yohkoh Mission are now available for scientific and educational uses.

Yohkoh is a mission of the Japanese Institute for Space and Astronautical Science (ISAS), conducted in collaborations with scientists from the US and the UK who are supported by NASA and the SERC. The primary database for Yohkoh is at ISAS, but the Solar Data Analysis Center (SDAC) at Goddard Space Flight Center (GSFC) is now prepared to provide public access to these data according to an agreement between ISAS and NASA. This service will start in October, 1993, on the occasion of the second anniversary of the start of the data acquisition by Yohkoh, following its successful launch from the Kagoshima Space Center. More recent Yohkoh data will be placed in the archives at the SDAC and NSSDC at an appropriate time; the second year of data will be available sometime in early spring 1994, and data for the third and subsequent years will be released in a continuous manner when the data becomes one year old, as long as Yohkoh remains in operation.

This release will include data from the Soft X-ray Telescope (SXT), the Hard X-ray Telescope (HXT), the Bragg Crystal Spectrometers (BCS), and the Wide-band Spectrometers (WBS). Existing data reduction software will also be released to ensure the effective use of the data; the maintenance and up-grading of this software will be undertaken by the Yohkoh investigators.

Both the Yohkoh Team and ISAS sincerely hope that the release of these data will enhance the scientific return from the satellite, by promoting research in the wider solar physics community. We also hope that the release will contribute to the promotion of public interest in science, especially of the younger generation, through use of the solar images in educational material and in the popular press.

Although these data are now open for general use, the Yohkoh Team continues to invite collaborations in their analysis. The Team is willing to assist all those who wish to use the data to help ensure its correct handling (which naturally requires certain degree of care).

When the data are requested, all necessary information and software for analysis will be supplied together with the data by the Solar Data Analysis Center.

For more detailed information on the Yohkoh data, or on scientific collaborations, or if you have any technical or software questions, please contact the GSFC Solar Data Analysis Center, or the Yohkoh Team, at

Yohkoh Data Requests (Western Hemisphere, Africa, Asia outside Japan):
Solar Data Analysis Center
Goddard Space Flight Center, Greenbelt, MD 20771, USA
fax: +1-301-286-8403

Yohkoh Data Requests (Europe):
Yohkoh Data Archive Centre
Mullard Space Science Laboratory, University College London
fax: +1-301-286-8403

Questions about Yohkoh Software:
SDAC, NASA, indicated above,
or Yohkoh Team, ISAS, indicated above, but with
email: SolarSoft development

Prof. Y. Ogawara
Project Manager, Yohkoh Project

Web curator: Joseph B. Gurman
Responsible NASA official: Joseph B. Gurman, Facility Scientist, Solar Data Analysis Center
+1 301 286-4767

NASA Goddard Space Flight Center
Solar Physics Branch / Code 682
Greenbelt, MD 20771

Last revised 2007 March 21 - J.B. Gurman