Welcome to the analysis of Yohkoh data. This document is intended to help you use the Yohkoh software and to understand the Yohkoh databases and some of the instrument calibration issues. The Yohkoh software has been written mostly in IDL, or Interactive Data Language, which is a licensed software program available from Research Systems, Inc. In order to run the Yohkoh analysis software, you must have IDL Version 3.0 or later installed on your computer or workstation. The Yohkoh Guide assumes that the reader has some familiarity with IDL already. For specific IDL questions, you are encouraged to consult the IDL User's and Reference Guides.
The Yohkoh software is known to work currently on several Unix-based platforms (e.g., HP, Sun, Mips, DEC, SGI). It is also available for VMS computers, however, we recommend that Unix be selected for analysis of Yohkoh data if possible. The installation and upgrade procedures described in the Reference Guide support only Unix systems.
Before beginning, it may be helpful to refer to Chapters 1 and 2 of
the Reference Guide (Volume 2) which briefly describe the Yohkoh instruments
and also provide an introduction to the Yohkoh data and software
organization. More details about the instruments can be found in the
Instrument Guide (Volume 3). You will want to make sure the Yohkoh software
is set up on your computer. Talk to your local manager about
this or follow the installation procedure described in the appendix of
the Reference Guide for Unix-based machines. The installation
can be accomplished easily by those possessing a moderate amount of
Unix experience. Next, check that you have a .yslogin file on
your home directory. Then type the following command:
% source /.yslogin
You must type this command at the beginning of each new login session or see the Yohkoh Reference Guide about how to customize your .login or .cshrc file.
Next, if you have Yohkoh data files on your disk, you should be able
to start looking at data after typing:
to start the IDL software system. YODAT (described in the next section) is the most common way to read Yohkoh data files and display various information or, in the case of SXT, to display images. If you have not yet copied any Yohkoh data files to your computer's disk, you will probably want begin with sections 1.4 and 1.5 which describe how to read the Yohkoh data archive tapes.