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 "PROGRAMMING 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 "UGC" and "MAG", 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:
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.