The Abell Catalogue of Rich Galaxy Clusters by George O. Abell, Harold G.
Corwin, Jr. and Ronald P. Olowin has been compressed into a single file,
"abellcat.zip", using an the compression/archiving program "PKZIP".  The
Catalogue may be unpacked using the companion program "pkunzip", both of 
which are contained in the shareware program "pkz204g.exe".  pkz204g.exe 
is a self-extracting file which also includes several associated programs 
and documentation.  Some basic information about it is in the "readme.pkz"
file.

There are four catalogue files, "nabell.clu", "sabell.clu", "rich.clu", and
"poor.clu"; and one explanation file, "columns.clu".  All are formatted for
easy use on computer terminals and monitors with 80-column displays.  The
explanation file has brief descriptions of the data and format of the
catalogue files.

The Notes to the catalogue are in "aconotes.zip" and may be extracted in the
same way shown below for the catalogue files themselves.

To extract the catalogue files:

  1) Copy the abellcat.zip file to a hard disk directory with AT LEAST 
     2 Mbyte free space.

  2) Copy the self-extracting zip file "pkz204g.exe" into the same hard disk
     directory.  Then, type:
     
     pkz204g
     
     This will unpack the archiving programs and documentation.

  3) To unpack the zip file, type:

     pkunzip abellcat
     
The unpacked files are 7-bit ASCII files, so they may be easily moved between
computers, or loaded into a database manager.