Copernicus Search Help

There are two search pages for Copernicus data: the Raw Data Search page and the Coadded Scan Search page. Since most of the search fields are identical on the two pages, this help page applies to both. Raw data includes scans from all the Copernicus detectors with data for a particular target all stored in one (variable length array) FITS file. Coadded scan data is comprised of coadded U1 and U2 scans (taken close in time) and stored in fixed length vector binary table FITS files.

The search pages basically contain 3 parts. The top of the page lists the input search fields. Entering values (as described below) for one or more of these fields will define the selection criteria for the database search. The middle of the form contains buttons to initiate various actions including:

  1. perform the search using the specified search criteria and output format,
  2. clear the search form and reset values to the original defaults,
  3. reset entries to the set of (default) values used the previous time the search page was drawn, and
  4. display this help page.
The bottom portion of the page deals with formatting the table of found entries that appears after the search is completed. The format options include specifying which columns appear in the output list, the order of the entries, the maximum number of returned entries, the epoch of the output coordinates, and the option to display the actual SQL command used to retrieve the database entries. First time users may want to run the search using the default output options.

After selecting search criteria, output options, and clicking the search button, a second page will appear listing the returned database entries. From this table, one may click on the object name to either display the FITS header for a raw data search, or display a plot of coadded counts versus wavelength for a coadded scan search. Clicking on the filenames for either catalog will download the selected FITS file.

Start Date
The date and time, in GMT, on which the first exposure of a coadded scan was started. More precisely, it is the time in which the satellite crosses the longitude of the ascending node (LAN) for the orbit in which the earliest exposure was taken. (The actual start time is obtained by adding the FIRST SET time to the OBSERVATION TIME entry as described in Observation Time Correction .) The Copernicus satellite operated roughly from August, 1972 to February, 1981.

When specifying this date, you need to include at least a date; a time is optional. The date can have any of the following formats (the month name can be spelled out or abbreviated to three letters; case is not significant):

      Jul 15 1994
      Jul 1994 15
      15 Jul 1994
      1994 Jul 15
      1994 15 Jul
      7/15/1994
      7-15-1994
      7.15.1994
    
If the day is omitted, the first day of the month is assumed. This means that a specification like "July 1994" will look for observations done on July 1 1994 00:00:00, not for observations done during July 1994. Note also that when entering a date with the month in numerical format, the American ordering is used; i.e., the first number is the month.

If a time is omitted, then any time for that day will match. Otherwise, you can specify a time in any of these formats:

      14:30
      14:30:20
      14:30:20:999
      14:30:20.9
      4am
      4 PM
      04:30:20 AM
    
To search for observations before a given date, use <, and for observations after a given date, use >. For example,
      > Jul 15 1994
      < Jul 15 1994
    
You can use the .. operator to search on a range of dates:
     Jul 1 1994 .. Aug 1 1995
   
This operator is inclusive on the first date and exclusive on the second.

Finally, you can search on a list of dates or date ranges. For example,

     Jul 1 1994 .. Jul 3 1994, Dec 1 1995 .. Dec 6 1995
   
will search for observations done within either one of these date ranges.

Category
IUE Object class code. The IUE classification system used for categorizing Copernicus observations. The object class was originally specified by the IUE Guest Observer. Only those object classes appropriate for Copernicus observations are listed (i.e., classes 1 through 83). Note more than one object class can be specified for the search by clicking on multiple entries from the object class table.

Min Wave
The minimum wavelength in the coadded scan, specified in Angstroms. Note coadded scan wavelengths are resampled to 0.01 Angstrom intervals.

Max Wave
The maximum wavelength contained in the coadded scan, specified in Angstroms. Note coadded scans are resampled to 0.01 Angstrom intervals.

Detector
Coadded scans have been generated for the U1 and U2 detectors. The U1 detector covers the 710-1500 A range at 0.05 A resolution, while U2 covers 750-1645 A at 0.2 A resolution.

Note the raw data sets contain data for all six detectors (i.e., u1,u2,u3,v1,v2,v3). V1 and V2 cover roughly the 1550-3200 A region at 0.1 and 0.4 A resolution respectively, while U3 and V3 are fixed in wavelength and used only for monitoring spacecraft pointing.

Spectral_Type
The spectral type of the observed star as derived from the Yale Bright Star Catalog (YBS5). Generally the spectral type is a measure of the star's temperature. Spectral type is designated using the Morgan-Keenan spectral classification system, and is specified as one of ten letters (OBAFGKMRNS) followed by a number from 0 to 9 designating subdivisions. The hottest stars observed are generally around type O3. Only those spectral types found in the Copernicus catalog however, are listed in the seach page. Spectral type is not appropriate for non-stellar objects (e.g., galaxies, planets, etc.), so the field may be left blank. Note the returned catalog listing will display the full spectral classification including the spectral type and the luminosity class.

Filename
The assigned file name. The raw data sets file names use the naming convention Cnnn.PEP where nnn is the 3-digit observation number assigned by Princeton Observatory describing the order in which targets were observed (i.e., the first observed target is named C001.PEP and the last target is C558.PEP).

The coadded scan file names are defined as Cnnn-###.ext where ### is a 3-digit number describing the order in which the scans were coadded (i.e., the maximum is 297), and ext is either .uu1 for unblocked u1 scans, .bu1 for blocked u1 scans, or .u2 for u2 scans.

Note wildcards can be used in the filename specification.