Thorium-Argon Atlas

Purpose of the Atlas

This page provides an atlas of UVES Thorium-Argon spectra as obtained in the UVES standard settings. The atlas can be used to identify individual Thorium-Argon lines to generate wavelength calibration solutions. In addition, the FITS table with the wavelengths of the Thorium-Argon lines is provided.

Note: this is based on an older version of the UVES Thorium-Argon atlas. The current version of the atlas is included in the UVES pipeline kit files and is installed as part of any Reflex installation including UVES. For information and retrieval, please see this link.

Content of the Atlas

  • 2D images of the Thorium-Argon frames with
    • the instrument setup identified on the top,
    • the running number of the (extracted) orders to the left,
    • the absolute order numbers to the right.
  • plots of all extracted 1D orders with
    • the extracted order numbers, the absolute order numbers, and the instrument setups identified on the top,
    • the extracted Thorium-Argon spectra in x-pixel coordinates
    • the lines identified by their wavelength (in blue)
  • resolution plots as derived from the extracted Thorium-Argon spectra

Background information

  • The Thorium-Argon exposures have been taken with the following instrument settings:
    • slit width: 0.5 arcsec
    • exposure time: 15 s
    • CCD setup: readout-speed 225kHz, low gain, 1x1 binning
  • The CCD frames have been extracted and flipped/transposed with theSPLIT/UVES tool available in the MIDAS context uves:
    • the overscan regions are removed
    • the orders are oriented to have a positive slope
    • wavelengths are increasing from bottom to top

Download section

Thorium-Argon linetable in FITS-table and ASCII formats. This linetable contains in computer readable form all Thorium-Argon lines which are identified in the atlas.
The Thorium linelist is based onPalmer, B. A., & Engleman, R. Jr. 1983, Atlas of the Thorium spectrum,Sinoradzky H. (ed.), Los Alamos National Laboratory, and lines are selected according to R=100000 spectroscopy based onde Cuyper, J.-P., & Hensberge, H. 1998, A&AS, 128, 409.
For the Argon lines, the reference isNorlén, G. 1973, Phys. Scripta, 8, 249.
The table has been edited to provide blend-free lines for a resolving power of R=100000. In the near-IR, lines have been added to improve the dispersion solutions.


Echelle CD wave atlas file
Blue #1 346nm
Blue #2 390nm
Blue #2 437nm
Red #3 520nm
Red #3 564nm
Red #3 580nm
Red #4 860nm