The Yohkoh data are organized into three general parts.
It is assumed that you have successfully installed the Yohkoh software on your system or you are using a machine that has the Yohkoh software. In addition to having made the software installation, it is necessary to have executed the Yohkoh initialization routine (`/ys/gen/script/idl_setup' or `.yslogin' for the Unix machines). If you have not done this yet, see the Appendix of the Yohkoh Reference Guide.
The Yohkoh software is organized under one tree. The top directory is $ys for Unix systems, and is the logical YS: for the VMS systems. Under that tree are the following branches:
| Branch | Description |
| SITE | Site specific software |
| GEN | General software and documents that all instruments can use |
| BCS_F77 | BCS FORTRAN specific software and documentation |
| BCS | BCS specific software and documentation |
| HXT | HXT specific software and documentation |
| HXT_F77 | HXT FORTRAN specific software and documentation |
| SXT | SXT specific software and documentation |
| WBS | WBS specific software and documentation |
| ATEST | Newly created or modified software and documentation |
| UCON | User Contributed software and documentation |
| IDLFIX | Work-arounds for systems using older IDL versions |
Under each of the above instrument directories, there are the following directories (for example, `/ys/sxt/doc')
| Branch | Description |
| DOC | Documentation |
| RESPONSE | Instrument calibration and response data files |
| SOFT | Software |
| STATUS | Instrument status information |
Software that has been thoroughly tested is put into the instrument release directory `soft'.1 Software which has just been written, or software that is modified is put into the `atest' area for a period of a few weeks. Certain privileged users have write privilege to those directories. If problems develop with modified software, it is possible to recover the old version by copying it from the `soft' directory. The software developed by general users is placed online under the `ucon' (user contributed) branch. Generally each user who is contributing has a directory of their own. The directories under the `soft' branch are broken up by function for the `gen' and instrument branchs, but by person under the `ucon' branch. If a user cannot remember the name of a function, he/she can do a listing on the different directories and will probably recognize it. A list of the directories that currently exist for the instrument teams is:
| GEN | BCS | HXT | SXT | WBS |
| dbase | bda | util | register | util |
| gbo | bsc | sensitivity | ||
| jhuapl | bsd | util | ||
| mo_disk | to_be_deleted | widgets | ||
| movie | util | |||
| orbit | ||||
| pointing | ||||
| ref_access | ||||
| reformat | ||||
| spectra | ||||
| tape | ||||
| util | ||||
| utplot |
See the appendix of the Reference Guide.
Picture Omitted
For a full description of the Yohkoh database and all the different data structures, see the File Control Document.
Each file is logically divided into the following six sections. Some files will not use all the sections described below, but all will have a Pointer and File Header Section.
The program which reads the file learns from the Pointer Section how to read the rest of the file and where to go to get certain data.
The File Header Section provides information on what data are contained in the file, generally the extent of the time covered by the contents.
The Quasi-Static Section of the file contains index information that does not vary during the course of an orbit, or varies slowly.
The Index and Data section contains `data sets'. A data set is a single image for SXT, single spectrum for BCS, a single major frame of data for HXT, and two major frames of data for WBS (it takes two major frames for a complete set of WBS data). For each data set there is an index which describes the date and time that the data were taken, the mode and position of the instrument's peripherals (e.g., filters, HV), and information on temperature and gain information.
The Optional Data Section is only used by the BCS data (BDA) files and the spacecraft attitude (ADA) files. The BDA files hold the `DP_SYNC' information, which is information that is coming down every major frame. Since the BCS spectra are asynchronous to the major frames, it is stored separately. The ADA file holds the full 2048 point HXA scans.
The Roadmap Section allows a user to access a brief summary of the contents of the file and to perform searches on that summary to select what data should be extracted.
There is a set of VMS logicals and Unix environment variables which point to the database directories. By using these logicals in all of the access routines (along with the routine CONCAT_DIR) it is possible for software to be directly portable between VMS and Unix machines. The following is a list of the logicals that exist for the Yohkoh database.
| DIR_GEN_ADS | DIR_SXT_ATABLES | DIR_BCS_ATODAT |
| DIR_GEN_ATR | DIR_SXT_CAL | DIR_BCS_BALDAT |
| DIR_GEN_ATT | DIR_SXT_CALIBRATE | DIR_BCS_CAL |
| DIR_GEN_DATA | DIR_SXT_DOC | DIR_BCS_CALDAT |
| DIR_GEN_DOC | DIR_SXT_ENGIN | DIR_BCS_CAT |
| DIR_GEN_EVN | DIR_SXT_SDC | DIR_BCS_DOC |
| DIR_GEN_FEM | DIR_SXT_SDL | DIR_BCS_EXE |
| DIR_GEN_GBE | DIR_SXT_SDW | DIR_BCS_LOGS |
| DIR_GEN_GBL | DIR_SXT_SENSITIVE | DIR_BCS_MICRO |
| DIR_GEN_GEV | DIR_SXT_SFC | DIR_BCS_SYNSPEC |
| DIR_GEN_GOL | DIR_SXT_SFM | |
| DIR_GEN_GXT | DIR_SXT_SFS | DIR_GBO_TEMP |
| DIR_GEN_MO | DIR_SXT_SLD | |
| DIR_GEN_MOVIE | DIR_SXT_SLS | |
| DIR_GEN_NAR | DIR_SXT_SOT | |
| DIR_GEN_NEL | DIR_SXT_SSL | |
| DIR_GEN_NTS | DIR_SXT_SSX | |
| DIR_GEN_OBD | DIR_SXT_SXA | |
| DIR_GEN_OBS | DIR_SXT_SXC | |
| DIR_GEN_ORBIT | DIR_SXT_SXL | |
| DIR_GEN_ORBIT_RAW | DIR_SXT_SXL2 | |
| DIR_GEN_ORBIT_SOL | DIR_SXT_TABLES | |
| DIR_GEN_ORBIT_SW | ||
| DIR_GEN_OSF | DIR_WBS_CAL | |
| DIR_GEN_OSP | ||
| DIR_GEN_OWH | DIR_HXT_CAL | |
| DIR_GEN_PAN_LASER | DIR_HXT_EXE | |
| DIR_GEN_PNT | ||
| DIR_GEN_SCRIPT | ||
| DIR_GEN_SETUP | ||
| DIR_GEN_SETUPD | ||
| DIR_GEN_SETUPDBACK | ||
| DIR_GEN_SPECTRA | ||
| DIR_GEN_STATUS | ||
| DIR_GEN_SYNOPTIC | ||
| DIR_GEN_TAPECOPY | ||
| DIR_GEN_TBB | ||
| DIR_GEN_XAD | ||
| DIR_GEN_XBD |
| Prefix | Description | File Type |
| ADA | S/C Attitude Raw Reformatted Data | per Orbit |
| ATR | Raw S/C Attitude Database | Weekly |
| ATT | Processed S/C Attitude Database | Weekly |
| BDA | BCS Raw Reformatted Data | per Orbit |
| BSD | *OLD* BCS Instrument Calibrated Spectra | User Specified |
| BPC | *OLD* BSDCAL Output (parameters) | User Specified |
| BTH | *OLD* BSDFIT Output (Fitted Spectra) | User Specified |
| BFT | *OLD* BSDFIT Output (parameters) | User Specified |
| BSC | *NEW* BCS Instrument Calibrated Spectra | User Specified |
| BSA | *NEW* Answer File for BSC Generation | User Specified |
| BSF | *NEW* Output from Spectral Fitting | User Specified |
| CBA | S/C Common Basic Raw Reformatted Data | per Orbit |
| EVN | Yohkoh Event Log | Weekly |
| FEM | Yohkoh Orbital Ephemeris | Weekly |
| GEV | GOES Event Log | Weekly |
| GXT | GOES One Minute Light Curve Data | Weekly |
| G6D | GOES 3 Sec Light Curve for S/C 6 | Weekly |
| G7D | GOES 3 Sec Light Curve for S/C 7 | Weekly |
| GXD | GOES Derived One Minute Light Curve Data | Weekly |
| GBE | GRO BATSE Event Log | Mission |
| GBL | GRO BATSE Light Curves | Weekly |
| G_x | Ground-Based Observation (GBO) Images (Sites) | per Image (FITS) |
| Gx_ | Ground-Based Observation (GBO) Images (Data Type) | per Image (FITS) |
| GBC | GBO Big Bear Large Scale H-alpha PFI FITS Image | per Image (FITS) |
| GBH | GBO Big Bear H-alpha FITS Image | per Image (FITS) |
| GBK | GBO Big Bear Calcium FITS Image | per Image (FITS) |
| GBW | GBO Big Bear White Light FITS Image | per Image (FITS) |
| GCH | GBO Boulder Colorado H-alpha FITS Image | per Image (FITS) |
| GGH | GBO GSFC H-alpha FITS Image | per Image (FITS) |
| GHH | GBO Holloman H-alpha FITS image | per Image (FITS) |
| GLH | GBO Leamonth Australia H-Alpha FITS Image | per Image (FITS) |
| GNH | GBO NAOJ Japan H-alpha FITS Image | per Image (FITS) |
| GJH | GBO CRL Hiraiso H-alpha FITS Image | per Image (FITS) |
| GKI | GBO Kitt Peak He 10830 FITS Image | per Image (FITS) |
| GKM | GBO Kitt Peak Magnetogram FITS Image | per Image (FITS) |
| GNP | GBO Nobeyama Polarized Radio Image (17 GHz) | per Image (FITS) |
| GNT | GBO Nobeyama Total Intensity Radio Image (17 GHz) | per Image (FITS) |
| GOL | GBO Observing Log | Weekly |
| Prefix | Description | File Type |
| HDA | HXT Raw Reformatted Data | per Orbit |
| HXI | HXT Synthesized Image | User Specified |
| MDM | Magneto-Optical (MO) Map | Mission |
| NAR | NOAA Active Region | Weekly |
| NEL | Nobeyama Radio Observatory Event Log | Mission |
| NTS | Nobeyama Radio Observatory Time Series | Weekly |
| OBS | *OLD* Yohkoh Observing Log | Weekly |
| OBD | BCS Observing Log | Weekly |
| OSF | SXT Full Frame Observing Log | Weekly |
| OSP | SXT Partial Frame Observing Log | Weekly |
| OWH | WBS/HXT Observing Log | Weekly |
| PNT | *OLD* S/C Pointing File | Weekly |
| SDL | SXT Dark Current Log | Weekly |
| SDC | SXT Dark Current Images | Weekly (SDA) |
| SDW | SXT Dark Current Images for Warm CCD | Weekly (SDA) |
| SDP | SXT Dark Current PFI Images | Weekly (SDA) |
| SFD | SXT FFI Desaturated Composite Images | Weekly (SDA) |
| SFR | SXT FFI Raw Reformatted Data | per Orbit (SDA) |
| SFS | SXT FFI Special Images (diffuser, flood...) | Weekly (SDA) |
| SFT | SXT FFI Terminator Images | Weekly (SDA) |
| SFW | SXT FFI White Light Images | Weekly (SDA) |
| SFC | SXT FFI Calibration (Leak) Image | per Image (SDA) |
| SFM | SXT FFI Monthly File (daily SFD image) | Monthly (SDA) |
| SLS | SXT Leak Scatter Log | Weekly |
| SLD | SXT Leak Dark Current Log | Weekly |
| SPR | SXT PFI Raw Reformatted Data | per Orbit (SDA) |
| SOT | SXT Optical Telescope Log | Weekly |
| SSC | SXT Synoptic Images (centered) | Weekly (SDA) |
| SSE | SXT Synoptic Images (east of center) | Weekly (SDA) |
| SSW | SXT Synoptic Images (west of center) | Weekly (SDA) |
| SSL | SXT Summary Log | Weekly |
| SXC | SXT X-Ray Sun Center Log | Weekly |
| SXL | SXT X-Ray Histogram Log | Weekly |
| SXA | SXT X-Ray Average | Weekly |
| WDA | WBS Raw Reformatted Data | per Orbit |
| XAD | Exabyte ASCII Directory for Archive Tape | Weekly per Tape |
| XBD | Exabyte Binary Directory for Archive Tape | Weekly per Tape |
The orbit file ID's are 11 characters long in the format shown below:
YYMMDD.HHMM
where YY - Year of data
MM - Month of data
DD - Day of data
HH - Hours
MM - Minutes
The Yohkoh week starts on Sunday and ends on Saturday. CAUTION: Yohkoh data taken at 00:01 (one minute after midnight) on Sunday morning is most likely in a file and tape for the previous week since the orbit started on Saturday and the first full orbit for Sunday has not started. Up to the first 90 minutes of data taken on Sunday could be stored in the previous week, depending on when the spacecraft day begins.
The weekly IDs are of the form:
YY_WWa.NN
where YY - Year of data
WW - Week number of the data (1 to 53)
a - is fixed (reserved for future use)
NN - is the program version number which created the file
A list of the dates covered by each of the weeks is given in Appendix xxx.
The Carrington IDs are of the form:
_crRRRRa.NN
where cr - signifies a Carrington Rotation ID
RRRR - is the rotation number
a - is fixed (reserved for future use)
NN - is the program version number which created the file
The dates for the Carrington Rotations are defined in the
table.
| Carrington | Starting Date | Carrington | Starting Date | Carrington | Starting Date |
| Rotation | Rotation | Rotation | |||
| 1846 | 21-Aug-91 | 1888 | 10-Oct-94 | 1930 | 29-Nov-97 |
| 1847 | 18-Sep-91 | 1889 | 6-Nov-94 | 1931 | 26-Dec-97 |
| 1848 | 15-Oct-91 | 1890 | 3-Dec-94 | 1932 | 22-Jan-98 |
| 1849 | 11-Nov-91 | 1891 | 31-Dec-94 | 1933 | 18-Feb-98 |
| 1850 | 8-Dec-91 | 1892 | 27-Jan-95 | 1934 | 18-Mar-98 |
| 1851 | 5-Jan-92 | 1893 | 23-Feb-95 | 1935 | 14-Apr-98 |
| 1852 | 1-Feb-92 | 1894 | 23-Mar-95 | 1936 | 11-May-98 |
| 1853 | 28-Feb-92 | 1895 | 19-Apr-95 | 1937 | 7-Jun-98 |
| 1854 | 26-Mar-92 | 1896 | 16-May-95 | 1938 | 5-Jul-98 |
| 1855 | 23-Apr-92 | 1897 | 12-Jun-95 | 1939 | 1-Aug-98 |
| 1856 | 20-May-92 | 1898 | 10-Jul-95 | 1940 | 28-Aug-98 |
| 1857 | 16-Jun-92 | 1899 | 6-Aug-95 | 1941 | 25-Sep-98 |
| 1858 | 14-Jul-92 | 1900 | 2-Sep-95 | 1942 | 22-Oct-98 |
| 1859 | 10-Aug-92 | 1901 | 29-Sep-95 | 1943 | 18-Nov-98 |
| 1860 | 6-Sep-92 | 1902 | 27-Oct-95 | 1944 | 15-Dec-98 |
| 1861 | 3-Oct-92 | 1903 | 23-Nov-95 | 1945 | 12-Jan-99 |
| 1862 | 31-Oct-92 | 1904 | 20-Dec-95 | 1946 | 8-Feb-99 |
| 1863 | 27-Nov-92 | 1905 | 17-Jan-96 | 1947 | 7-Mar-99 |
| 1864 | 24-Dec-92 | 1906 | 13-Feb-96 | 1948 | 3-Apr-99 |
| 1865 | 20-Jan-93 | 1907 | 11-Mar-96 | 1949 | 1-May-99 |
| 1866 | 17-Feb-93 | 1908 | 7-Apr-96 | 1950 | 28-May-99 |
| 1867 | 16-Mar-93 | 1909 | 5-May-96 | 1951 | 24-Jun-99 |
| 1868 | 12-Apr-93 | 1910 | 1-Jun-96 | 1952 | 22-Jul-99 |
| 1869 | 10-May-93 | 1911 | 28-Jun-96 | 1953 | 18-Aug-99 |
| 1870 | 6-Jun-93 | 1912 | 26-Jul-96 | 1954 | 14-Sep-99 |
| 1871 | 3-Jul-93 | 1913 | 22-Aug-96 | 1955 | 11-Oct-99 |
| 1872 | 30-Jul-93 | 1914 | 18-Sep-96 | 1956 | 8-Nov-99 |
| 1873 | 27-Aug-93 | 1915 | 15-Oct-96 | 1957 | 5-Dec-99 |
| 1874 | 23-Sep-93 | 1916 | 12-Nov-96 | 1958 | 1-Jan-00 |
| 1875 | 20-Oct-93 | 1917 | 9-Dec-96 | 1959 | 29-Jan-00 |
| 1876 | 17-Nov-93 | 1918 | 5-Jan-97 | 1960 | 25-Feb-00 |
| 1877 | 14-Dec-93 | 1919 | 1-Feb-97 | 1961 | 23-Mar-00 |
| 1878 | 10-Jan-94 | 1920 | 1-Mar-97 | 1962 | 19-Apr-00 |
| 1879 | 6-Feb-94 | 1921 | 28-Mar-97 | 1963 | 17-May-00 |
| 1880 | 6-Mar-94 | 1922 | 24-Apr-97 | 1964 | 13-Jun-00 |
| 1881 | 2-Apr-94 | 1923 | 22-May-97 | 1965 | 10-Jul-00 |
| 1882 | 29-Apr-94 | 1924 | 18-Jun-97 | 1966 | 6-Aug-00 |
| 1883 | 26-May-94 | 1925 | 15-Jul-97 | 1967 | 3-Sep-00 |
| 1884 | 23-Jun-94 | 1926 | 11-Aug-97 | 1968 | 30-Sep-00 |
| 1885 | 20-Jul-94 | 1927 | 8-Sep-97 | 1969 | 27-Oct-00 |
| 1886 | 16-Aug-94 | 1928 | 5-Oct-97 | 1970 | 24-Nov-00 |
| 1887 | 13-Sep-94 | 1929 | 1-Nov-97 | 1971 | 21-Dec-00 |
Most of the Yohkoh software is written in the programming language IDL of Research Systems, Inc (RSI). If certain rules are followed, then the same IDL software can be run on a wide variety of computers.
In using IDL it is very easy to create too many variables to the point where
the computer memory capacity is exceeded.
It is possible to delete old
variables by using the DELVAR command. For example, if you wanted to delete
the variable DATA, you would type:
IDL > delvar, data
There is a peculiarity about using the IDL routine FINDFILE and using the
Unix symbol ~ for the user's home directory. FINDFILE does not return any
files when using the command:
IDL > ff = findfile(' ~ /*')
It is recommended to use the full path (for example `/2p/morrison/*') instead
of ~ .
It is possible to change the default directory from within IDL by using
the IDL command ``cd''. Some sample commands are:
IDL > cd, ' ~ '
IDL > cd, '/yd3'
The following will NOT work since it sets the default for the sub-process
and then exits that process.
;WILL NOT WORK
For Unix machines, it is possible to press control-z to place an
IDL session in the background so that you can do some work from the Unix
system. When you are ready to go back to the IDL session, type:
% fg
Be careful to remember that you have an IDL session hidden in the background
since you can waste memory and corrupt the color table settings if you
have multiple IDL sessions going.
An IDL main program requires a .RUN command to run, and the code within that file starts executing after successful compilation.
An IDL procedure is a kind of subroutine and has something like
PRO PROCEDURE_NAME, PARAM1, PARAM2
at the top of the file. The variables in the procedure definition can be input
or output. It is possible to have keywords with a command like
PRO PROCEDURE_NAME, KEY1=KEY1, KEY2=KEY2
It can be executed with a command like:
IDL > procedure_name, a, b
IDL > procedure_name, a, b, key1=c
An IDL function is another kind of subroutine and has something like
FUNCTION FUNCTION_NAME, PARAM1, PARAM2
at the top of the file. The primary output is passed to result
but it is possible to have parameters in the call which can receive output.
It is executed with a command like:
IDL > result = function_name(a,b)
When running on a Unix system, it is important to use lower case when using the .RUN command because Unix is case sensitive. This is not necessary when doing an `implied' compilation when accessing procedures or functions since IDL will convert to lower case for you. You cannot use upper case for a procedure to do an explicit compilation (.RUN PROCEDURE_NAME) to recompile a procedure.