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The Alpha Canis Majoris (Sirius) Spectral Atlas

[Alpha CMa Sample Spectrum]

The primary reference for the Copernicus Spectral Atlas of Sirius is Rogerson, J. B., (1987ApJS...63..369R). The summary information that follows is taken from that reference.

The observations obtained to construct this atlas were obtained primarily during the periods 1977 March 5-8, 1977 March 12-16, and 1977 March 18-April 5. There were several gaps in the coverage of this data; these were filled in with observations obtained during the period 1981 February 8-9. A gap starting at 2292.7 Å was overlooked. The spectral atlas covers wavelengths from 1649 Å to 3170 Å, with a spectral resolution of 0.1 Å. The scans were made in the V1 detector. A complete description of the Copernicus science instrument may be found in Rogerson et al. (1973ApJ...181L..97R).

Wavelengths were corrected for Doppler shifts due to (a) the heliocentric radial velocity of Sirius, (b) the Earth's heliocentric velocity in the direction of Sirius, and (c) the component of the satellite geocentric orbital velocity in the direction of Sirius. The counts from the source were corrected for counts due to cosmic rays and trapped charge particles, guiding errors and scattered light within the spectrometer. No correction was made for the wavelength variations in the spectrometer sensitivity.

The atlas is a compilation of 36 separate scans of specific spectral regions. There are a total of six files, numbered 2-7 (following the original NSSDC file numbering scheme). File 2 contains the counts for the vacuum spectrum; file 3 contains the normalizing continuum and scattered light values for the vacuum spectrum; file 4 contains the line identification table for the vacuum spectrum; file 5 contains the counts for the air spectrum; file 6 contains the normalizing continuum and scattered light values for the air spectrum; and file 7 contains the line identification table for the air spectrum. 

   FILENAME    ROWS   FIELDS  WVE_FRST  WVE_LST     TYPE

alphacma2.fts  7119     3     1648.786  2005.380   vacuum spectrum
alphacma3.fts    74     3     1645.000  2010.000   norm. cont. 
alphacma4.fts  1351     8     1649.20   1999.73    id table vacuum
alphacma5.fts 28062     3     2004.004  3171.556   air spectrum
alphacma6.fts   236     3     2000.000  3175.000   norm cont
alphacma7.fts  4089     8     2000.00   3170.00    id table air