Previous: Overview
Up: Aspects of a simple-minded ARCQUERY session
Next: Input/Output tables
Previous Page: Overview
Next Page: Input/Output tables

SELECTions

The SELECT command (section ) acts, in principle, on all items in the observations catalogue, and on some derived quantities. A complete list of keywords used with SELECT is given in table ; a short list of items of interest for first-time users includes:

- Name of the observer (up to 4 initials)               keyword: INI
- Name of the telescope                                          TEL
- Name of the instrument                                         INST
- Detector name                                                  DET
- Object name (up to 24 characters)                              OBJECT
- Object type (up to 4 code numbers)                             OBJ_TYPE
- Observation type (coded, e.g. arc/flat/object/standard)        OBS_TYPE
- RA and/or DEC, or position                                     RA, DEC, POS
- Date of observation                                            DATE
- Exposure time                                                  EXPO
- Waveband (filter) information                                  WAVEB

Simple selections can be as follows:

SEL INI=EJZ : get all observations taken by observer EJZ

SEL DET=IPCS : get all observations taken with the IPCS

SEL OBJECT=3C273* : get all objects whose name starts with 3C273

In the last example the wild card `' can be useful, because many observers add some brief comment or clarification to the object name. If the wild card is not specified, the archive will only search for object names 3C273 strictly, and everything else is ignored. Note, however, that the use of wildcards will slow down the search. Further note that blanks in object names (and other character keywords) are ignored unless the user does explicitly specify blanks in the select command (section ). Thus:

SELECT OBJECT=3C273 : will find 3C273, but also e.g. 3C 273 or 3 C 273, even 3 C 2 7 3

SELECT OBJECT=3C 273 : finds 3C 273 or 3 C 273, but not 3C273

During the search the SELect command may generate a listing of the selected observations (depends on the default setting, which in its turn depends on the access mode to the captive account used). Such a listing can be suppressed by giving an interrupt <CTRL/C> and continue with NOLIST, or by using CTRL/L, or, straight from the beginning with the NOLIST qualifier in the SELECT command itself:

SEL/NOLIST... etc.

If the default is set to NOLIST, then, after a select process is completed, a message appears stating the number of records selected. One may choose to list the table with "LIST"; alternatively, the /LIST qualifier may be used directly with the SELECT command itself:

SEL/LIST... etc.