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Copernicus Coadd Search Output Columns
The entries below represent:
- The columns displayed after searching the raw or coadded scan database,
- the fields included in both the Copernicus raw data table and the coadded scan database table,
- except for the last 3 entries (i.e. "detector", "row" and "more info") and noted exceptions, they define the FITS keywords contained in the primary headers of these two data sets.
Although most of the definitions are the same in the two data sets/tables, there are a few instances in which the fields only exist in one or the other, or have slightly different definitions. These exceptions are all noted below.
- Object Name
-
The object names as obtained from the Princeton University Observatory,
presumably as specified by the observer.
Examples of valid names include ZETA OPH, JUPITER, and HD 14633.
Note the file names are all stored in upper-case, but the database
search software is case-independent.
For coadded scan searches only, clicking on an OBJECT NAME entry will display a GIF-format image plotting the individual and coadded scans as a function of wavelength, as well as the number of points and the scatter about the mean for each coadded data point. Note the coadded scan is drawn in histogram mode whereas indiviual scans are plotted using straight line segments between data points.
An option to customize the coadded spectrum is also available from this page. Clicking the button shown will display a forms page with options to change the scans being coadded as well as several processing and plot display options. An option on the final results page allows the counts and wavelengths to be downloaded as an ASCII table file.
- A number from 0 to 99 used for categorizing objects - based on the International Ultraviolet Explorer ( IUE ) object classification code. (Note the object class was only included in the Copernicus database table and does not appear in any FITS headers.)
- Object's Right Ascension in Epoch 2000 coordinates, as obtained from the Yale Bright Star (YBS) Catlogue Version 5, and specified in decimal degrees. (Note: epoch 1950 coordinates were originally the standard for the Copernicus Project.) Objects not found in the YBS catalog contain the original OAO3 entries precessed to epoch 2000. In a few cases, (i.e. file numbers 184, 192, 243, 260, 262, 304, 307, 313, 314, & 321), the OAO3 values were felt to be incorrect and were revised. (The FITS keyword comment for these entries will include the phrase "modified"). For solar system objects, the RA is arbitrarily set to 360.00.
- Object's declination in Epoch 2000 coordinates specified in decimal degrees, as obtained from the Yale Bright Star (YBS) Catlogue Version 5. (Note: epoch 1950 coordinates were originally the standard for the Copernicus Project.) Objects not found in the YBS catalog contain the original OAO3 entries precessed to epoch 2000. In a few cases, (i.e. file numbers 184, 192, 243, 260, 262, 304, 307, 313, 314, & 321), the OAO3 values were felt to be incorrect and were revised. (The FITS keyword comment for these entries will include the phrase "modified"). For solar system objects, the DEC is arbitrarily set to 0.0.
- The raw (i.e., as delivered by Princeton to NASA) scans are in FITS files named "cnnn.pep" where "nnn" is the Copernicus Master Star Number. The first object observed by Copernicus is number 001, the second object observed is number 002, etc. through 558. Within each raw data file, the scans are stored chronologically with the earliest scan first.
The coadded scan file names are defined as "cnnn-###.ext" where nnn refers to the raw data file number, ### is the order in which the scans were coadded (grouped chronologically with with the earliest ones first), and ext is either .uu1 for unblocked u1 scans, .bu1 for blocked u1 scans, or .u2 for u2 scans.
Clicking on an entry in the FILENAME column will download the FITS-format file to the users local disk.
- 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. (Note that since start dates are different for each scan, they are not listed in the raw file headers.)
- For coadded scans, the number of points in the final coadded spectrum. Values range from 3 to 9,000.
- For coadded scans, this is the scan number of the first (i.e., earliest) scan used in the coaddition. Values range from 1 to 23,000.
- For coadded scans, this is the scan number of the last scan used in the coaddition. Values range from 1 to 23,000.
- A measure of the target's color excess. The difference between the observed and the intrinsic color of the target which is generally caused by interstellar reddening. The color excess, E(B-V), was provided by the Princeton University Observatory. Values range from -0.3 to 1.2. (Note values may be out-dated.)
- A measure of the target's color; specified by the difference between the brightness observed in the blue and the visual portions of the spectrum using the U, B, V system of Johnson and Morgan. Values for the Copernicus data range from -0.3 to 2.4 and were obtained from the 5th edition of the Yale Bright Star Catalog.
- Rotational Velocity of the target in km/sec as derived from the Yale Bright Star Catalog Version 5. Values range from 0 to 450 km/sec.
- Object's heliocentric radial velocity in km/sec as provided by the Princeton University Observatory. (Note values may be out-of-date.) Valus range from -74 to 291 km/sec.
- Interstellar medium velocity in km/sec. provided by the Princeton University Observatory. Values in the Copernicus catalog range from -24 to 36 km/sec. (Note values may be out-of-date.)
- "Correction from the heliocentric radial velocity to a velocity with respect to the local standard of rest (in km/sec). This number is the dot product of a unit vector toward the star and a vector of length 20 km/sec pointing toward RA(1900) = 271 degrees; DEC = +30 degrees. Hence, one should _add_ the number to a heliocentric velocity to obtain the LSR velocity." (from Jenkins, Appendix A, p. 3). These values were provided by the Princeton University Observatory and range from -20 to 20 km/sec. (Note values may be out-of-date.)
- Distance to the star in parsecs as provided by the Princeton University Observatory. Values range from 1 to 16600 parsecs. (Note values may be out-of-date.)
- Galactic Longitude and Latitude in decimal degrees (from 0 to 360.) as calculated from the Right Ascension and Declination. (Note galactic coordinates appear only in the Copernicus database tables.)
- Galactic Longitude and Latitude in decimal degrees (from -90 to 90) as calculated from the Right Ascension and Declination. (Note galactic coordinates appear only in the Copernicus database tables.)
- The spectral type and luminosity class 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. Spectral type is not appropriate for non-stellar objects (e.g., galaxies, planets, etc.), so the field may be left blank. Luminosity class is designated using the Morgan-Keenan luminosity classification system, and is specified by a Roman numeral from I to VI, with finer subdivisions indicated by an appended a or b. Ia represents the most luminous class.
- The apparent visual magnitude of the observed object, as given by the 5th edition of the Yale Bright Star Catalog. Copernicus values range from -1.5 to 8.9.
- The absolute visual magnitude of the target is the visual magnitude of the target if it were at the standard distance of 10 parsecs. The values were obtained from Corbally C.J. and Garrison R.F., 1983, "Which Map of Absolute Magnitudes: Keenan or Schmidt-Kaler?", in "The MK Process and Stellar Classification", edited by Robert F. Garrison (Toronto, David Dunlap Observatory). Values range from -8.5 to 7.4.
- For raw data sets, this is the total number of scans contained in the Raw Data file and can range from 5 to 23,355. Scans from all 6 detectors are counted.
For coadded scan files, this is the number of co-added scans used to produce the final spectrum. Values range from 1 to 297; the larger numbers typically being obtained late in the mission when detector efficiency was low.
- The minimum wavelength in the coadded scan, specified in Angstroms. The minimum however may be either the first or last wavelength point depending on the scan direction. Note coadded scan wavelengths are resampled to 0.01 Angstrom intervals, and all wavelengths have been converted to a heliocentric frame of reference.
- The maximum wavelength in the coadded scan, specified in Angstroms. The maximum however may be either the first or last wavelength point depending on the scan direction. Note coadded scan wavelengths are resampled to 0.01 Angstrom intervals, and all wavelengths have been converted to a heliocentric frame of reference.
- 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 only used for monitoring spacecraft pointing. (Note detector is not a FITS keyword nor a database field.)
- The row number of each record in the results of your search.
- Clicking on one of the displayed archives will repeat the database search on the selected catalog, using the RA and DEC for the particular target selected. If the original search was on the Copernicus Raw data catalog, selecting "coadd" will repeat the search on the coadded scan catalog. If the original search was on the coadded scan catalog, selecting "raw" will repeat the search using the raw data catalog. This is a useful way to see what data is available for a given target in other catalogs.
Note that since coordinates are used to cross-reference targets listed in various catalogs, searching on moving targets may return spurious or invalid results.
- A number from 0 to 99 used for categorizing objects - based on the International Ultraviolet Explorer ( IUE ) object classification code. (Note the object class was only included in the Copernicus database table and does not appear in any FITS headers.)
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