What is

DIRA2 is a software structure that allows the astronomer to manage in a simple and articulate way the astronomical data files, expecially catalogues. The users can access this structure by a set of commands that activate specific procedures.

A subset of commands to retrieve data from DIRA2 database are available via DIRA2-WWW. The system can be used via telnet on servers or the user can get the software to manage personal data also. The on line manual or a postscrip file are available,

DIRA2 allows the creation and the management of a catalogue data base, either of general or private use (master and personal data base respectively). The manipulation of files, the extraction of subfiles by user defined criteria, and the iconographic view of results are supported by the command set.

For special user applications, a FORTRAN library exists that uses the same philosophy and the same conventions. The FORTRAN calls are described in the &quotPROGRAMMING in DIRA" manual.

The main feature of the DIRA2 philosophy is thet the catalogues and the variables,(e.g. Right Ascension, Declination, Magnitude etc...) are know to the system by conventional codes defined in a vocabulary. This means, in practice, that if one is interestsed on a list of magnitudes from the Uppsal General Catalogue, he needs to enter the keywords &quotUGC" and &quotMAG", besides, of course, other minor specifications on output etc...

About 240 catalogues are presently available in DIRA2. The users can insert other catalogues with a minimal effort. All the commands provide dafalult values and have an help structure.

Major differences between the classic interactive Dira2 and DIRA2-WWW (Web version) are that, with the classic version, the user can work with personal catalogues also and use them in the cross identification or in the merging operation of pubblic catalogues, moreover there are tools and graphic commands that was not implemented in Web version for lack of atomic interactivity in the Web server client philosofy. The Web version of Dira2 promote the data distibution in a easy and standard way.

DIRA2 main capabilities.

DIRA2 mainly performs the management of data files containing catalogues. The main actions are: creation of the data base, the updating, the query and data retrievial and the graphic representation of the output. The DIRA2 commands act on catalogues either on disk or tape. The catalogues can be in a public area, or in a private directory. Users can write catalogues, or selectdata from existing ones and manage them with the DIRA2 commands.

DIRA2 is able to:

    Provide the user with all the system available specifications: catalogue file location, names reading formats, entry codes in the catalogues record etc... One can also obtain astronomical documentation of the catlogue content.

    Create, manage, search, query and retrieve data from the Data Base.

    Create a new catalogue field as a function of existing fields, or create new catalogues as a junction of existing catalogues.

    Transform the astronomical coordinate system of the catalogues.

    Supply the user with some user_oriented utilities for the data display and graphic search. One can get maps (db_chart) (db_schart) , wedge diagrams (db_wedge) , histograms (db_histo) , regressions (db_regres) on graphic devices or workstations catalogue data can be retrivied by cursor location.

    Write and read catalogues and tables in FITS format.

    Provide the user with means to develop his own programs of a database use, by calling a library of FORTRAN subroutines.

Master and personal data base levels.

The distinction between master and personal data base (DB and PDB respectively) is both operational and philosophical. This distinction is a basic concept for the use of DIRA2.

The Master DB level is created by DataBase Administrator of a site and can be used by all users in read-only mode. The output of the query will produce one or more files that can reside in the Personal Data Base area, so the user can access them in read/write mode.

The personal data base is a complete subsystem used and managed by single user. DIRA2 system files are written in the user current directory at the time of creation of a PDB. In the Personal Data Base the user can insert his own catalogues, coming from previous selection, copied from other astronomical centers or created with a editor. A user can create more PDBs in separate directories, but he can access them one ata a time. Instead he can mix the access to the Master DB and Personal DB of DIRA2 commands.

What is a catalogue in DIRA2?

A catalogue in DIRA2 is an ASCII file, written in a table format, that contains one record for each astronomical object (.DAT files). The physical description of catalogue variables are written in DIRA2 system files (.DB files) and are used in a trasparent way by the DIRA2 commands. The users can investigate on these data to search for particular classes of catalogues in the data base with the DB_INFO command. At the PDB level, the users can manage these files using the PDB_MANAG command.

Moreover each catalogue has a related file (.DOC) that contains the documentation in a printable format. We have added to the available astronomical documentation some entries of informational use: number of records, code and format of the variables contained in each record, full explanation of adopted code etc. At the Personal Data Base level the user can create documentation file for self-created catalogues.

DIRA2 is a software developed by the Astronet Working Group on Database and Documentation. The following people contributed to the DIRA2 realization :

Software team:

R. Merighi, Osservatorio Astronomico, Bologna.

M. Nanni, Istituto di Radioastronomia, Bologna.

F. Tinarelli, Istituto di Radioastronomia, Bologna.

G. Stanghellini, Istituto di Radioastronomia, Bologna.

Catalogue and documentation:

P. Battistini, Dipartimento di Astronomia, Bologna

L. Benacchio, Osservatorio Astronomico, Padova

M. Cannizzaro, Istituto di Radioastronomia, Bologna

A. Gemmo, Osservatorio Astronomico, Padova

Suggestion, remarks and data:

S. Bardelli, Dipartimento di Astronomia, Bologna

G. Giovannini, Dipartimento di Astronomia, Bologna

R. Morbidelli, Osservatorio Astronomico, Torino

R. Pannunzio, Osservatorio Astronomico, Torino

M. Sarasso, , Osservatorio Astronomico, Torino

G. Vettolani, Istituto di Radioastronomia, Bologna.

A. Volpicelli, Osservatorio Astronomico, Torino

E. Zucca, Dipartimento di Astronomia, Bologna

Group Coordinator:

M. Nanni, Istituto di Radioastronomia, Bologna