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Дата изменения: Fri Jun 30 16:02:49 2000
Дата индексирования: Sat Dec 22 10:23:39 2007
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Поисковые слова: southern cross

Program parameters

Parameter input is done with a graphic user interface. The interface after program invocation is shown in fig. 1

  

Figure 1: Graphic user interface for program searchdup

Parameter to be sepcified are:

• Input file: Name of the input catalog file. It has to be formatted, one record per source/observation, according to the format used in the Arcetri observations and source archives.
• Format for input file: Two formats are available:
  • Osservazioni:, is the format used for spectral observations (scans). Fields are: RA, declination (DIRA format), frequency , band (MHz), date and time (string), scan number, galactic coordinates (b₂, l₂, in degrees), source name and project title (17 chars total, beginning in column 77, including space between name and title), and LSR velocity of band centre. At Arcetri, the stadard path for the observation database is:

    /home/thor2/archivio/diradata/SPT.SORT

  • Archivio: is the format used in the Arcetri water maser catalog. Fields are: IRAS and common names (total of 27 chars), RA, declination (DIRA format), class derived from FIR IRAS colors (string), date (string), bandwidth used (MHz) , scan number, RMS flux (Jy), vmin, vmax, vpeak (Km/s), peak flux (Jy), integrated flux (Jy Km/s). Only RA, dec, date, band and scan number are retained. At Arcetri, the stadard path for the catalog is:

    /home/thor2/archivio/diradata/H2O_ATLAS.TAB

  The input files are mantained using the DIRA package for astronomical catalogs.

  The format for the input date and time is yy/mm/dd hh:mm:ss. It is converted internally to years and fraction of years, with the convention that years 80-99 represent 1980-1999, and 00-79 represent 2000-2079. Four digits per year are also acceptable. It is important to note that the epoch in the output file will be represented as years from 1900, if two digits are used, or absolute years, if four digits are used. Obviously, consistence for the date representation in the input catalog is essential.

• Output file and format: The filename and format used for program output. Two formats are available.
  • Smongo For each group of sources at the same position, a comment (beginning with "#") record is printed, containing the following informations taken from a "representative" source: a sequential number, RA and declination (DIRA format), number of separate observations, and name. Subsequent records, one per observation, contain only numeric fields: sequential number of the source, epoch, band, and scan number.

    This format is useful for plotting the time coverage of a set of sources, plotting the first field (source ID) versus the second (epoch of observations).

  • Copy input simply copies the input catalog line for a representative source of the observations set. This format is useful for compacting a set of sources/observations, keeping only one representative position for each set of almost identical sky positions. Since the input files adhere to the DIRA format, the output file can be also processed using the DIRA package.

  The representative observation for each source is chosen as the first in time (date of observation) in the ordered data set of the observations. It is possible that it is not the best choice, e.g. its position or name can be quite atypical. The output catalog is sorted for decreasing number of observations.

• Delta time Number of days necessary to consider two observations as different. This is necessary to avoid considering a long integration as a set of several independent observations. It must be chosen as the minimum time at which variability may be relevant.
• Source minimum separation Angular separation between two observations necessary to consider them independent. Usually half beamwidth of the telescope.

• Minimum number of observations per source Source with less than this number of independent observations are not included in the output file

• Maximum number of records and sources Used for storage allocation. Must be greater than the actual number of records and sources