DB_FROMFT

COMMAND TYPE : UTILITY

PURPOSE:

To insert a FITS catalogue in DIRA.

DESCRIPTION:

This command loads in DIRA a catalogue written on tape or on disk in FITS format (XTENSION='TABLE'). Some catalogues written in FITS are distributed from computer centers, moreover some packages,i.e. ESO MIDAS, write tables data in this format, so the user can load in DIRA this tables. The command adjusts the catalogue data, and update the DIRA system. When the sky coordinates in the FITS catalogue do not agree with DIRA coordinate convention, the command converts these automatically.

The command DB_TOFITS : writes DIRA catalogue in a FITS format. When the task DB_FROMFT recognizes catalogue written by DB_TOFITS : it works in a fully automatically way and inserts catalogue in the data base without more instruction. So the use of the commands DB_TOFITS : and DB_FROMFT is the best way to interchange DIRA catalogues between computer centers.

INPUT FIELDS of the command:

Input FITS File name

The name of the input FITS file. When the file comes from a tape the user must enter here the name of the tape unit.

Example : MSA0:

For: PDB

The user can insert catalogues in the Personal Data Base or in the master data base (if authorized). If he wants to insert the catalogue in the PDB he must fill the field with a Y.

Example : Y

Output : Catalogue File Name

The name of the output file. The name of the catalogue will be picked-up from the FITS header.

Example : CATNEW.DAT

Tape: File No.

When the catalogue is on tape the user must insert here the sequential number of the file on the tape that he wants to get. When the user works with fits data on disk this field is not used.

Example : 17

EXECUTION:

The command starts reading the FITS header of the file. When the coordinates in the FITS file are written in a DIRA standard format the command recognize it and ask to continue in the file writing. The user can enter W to write the new catalogue without more questions.

When coordinates in the input file are not in a standard format, or when the user enter T to convert the format of the input coordinate the command opens two new windows on the screen. In the bottom window the first ten records of the catalogue are shown. In the top window are written the FITS keywords related with the fields.

The first column of the catalogue in the bottom window is shown in reverse, while in the top window the values of the FITS key of this column are shown. The user, with the left and right keyboard arrows can select other columns and read other FITS keys in the top window. So he can examine all the catalogue fields to understand the formats of the coordinates.

Then the user can mark the coordinates entering C key. The task will ask for the coordinate class (first coordinate = longitude or second coordinate = latitude) and for coordinate type (degrees, HH MM SS, radians and so on). When the user has defined the type of input coordinates he must use the keyboard arrows to select, in the bottom window, the field that contains the coordinate values. If the input catalogue has the coordinate written on more fields (i.e. hours, minutes, seconds) the command will ask to mark the hours field, then the minutes field and finally the seconds fields.

The user must mark all the coordinate fields that he needs to convert, (remember that DIRA can handle coordinates that are in a unique field). Then he can use E to start with the conversion and the output file writing. The CTRL-Z key will abort the task.

CONTROL KEY:

<- ->

With the left and right keyboard arrows the user can select the field on the bottom window. When he moves in a new field the FITS values are shown in the top window. When the program asks to mark a coordinate field the user must use the key to move in the desired column and then confirm with the RETURN or ENTER key.

C

The user must type this key when he needs to mark a coordinate field that must be converted to a DIRA format. When there are many coordinates fields to convert the user must type the C key for each field that he needs to convert. Then the command will asks to define the coordinate type in the input catalogue and the conversion required in the output catalogue. When there are no more coordinate fields the user can type the E key to continue.

E

Ends the interactive phase and starts to write, converting all the marked field.

CTRL-Z

Aborts the task. All the temporary files are deleted.

NOTE:
The user can define the name of the output data file. Moreover a .DOC file will be written in the user current directory. This file contains the FITS keywords found in the original file, and it can be useful in the writing of the documentation file.



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