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SpectroWeb News

January 2018

Linux Users: Please note that the SpectroWeb viewer uses Java applet technology. Users of recent versions of the Firefox and Chrome browsers should read the links below for help with activating Java and Java applets:



We advice installing other internet browsers for viewing spectra with the SpectroWeb applet. For example, the Pale Moon browser available at https://linux.palemoon.org/ supports applets and the NPAPI architecture. We installed and tested that the SpectroWeb spectra and datasets are correctly displayed with the Pale Moon browser.

Java Security Issues: Please make sure you set the required security fields in the Java Control Panel of your Java installation. Under the Security Tab you have to populate the Exception Site List with the 6 sites listed below from where SpectroWeb loads all its data:


The spectral segments of SpectroWeb are loaded and displayed in the applet viewer after you answer with Run the Security Warning message Java prompts.

October 2010

A large list of neutral atomic line identifications is now available in SpectroWeb 1.0 based on detailed spectral synthesis calculations of the optical spectrum of the Sun, Epsilon Eridani, and Procyon. These neutral lines are marked in black in the atomic line lists and offer validated atomic line data. The atomic line data in SpectroWeb are validated when the computed normalized line depths are within 3 % of the normalized line depths observed in these spectral standard stars. The restwavelengths of the validated lines are within 0.05 Å of the observed line flux minima in the Sun, and within 0.1 Å in Eps Eri. The validated lines are labeled with L10 and provide accurate empirical log(gf)-values we use to compute the theoretical spectra in SpectroWeb 1.0.
Further research work is in progress for compiling much more extensive lists in SpectroWeb with empirically validated log(gf)-values based on detailed spectral synthesis calculations of various stars. We are also searching for a high-quality optical spectrum of Canopus to evaluate the log(gf)-values for many more lines of ionic species.

September 2010

The optical spectra of Eps Eri, Procyon, and Arcturus are now completed using large S/N observations of Mercator-HERMES. The procedures for the placement of the continuum level have been further developed, yielding considerable improvement in the normalization of the new HERMES spectrum of Procyon. The theoretical optical spectra of these stars and the Sun have also been considerably improved using more accurate restwavelengths of many atomic lines in the synthesis calculations with the help of ROB summer student Mr. T. Hendrix.

December 2009

The Procyon spectrum between 3300 Å and 4700 Å is now available for comparison to the Sun. All corrected log(gf)-values have been included in the spectral synthesis calculations for this wavelength region as well.
An Epsilon Eridani plug-in has been uploaded on Dec 23. The new Mercator HERMES optical spectrum is complete with S/N ratios of up to ~2,000. Some issues with the correct placement of the continuum level remain though. Some of the auto-normalizer iterations had to be stopped manually. The faint molecular background is appreciably stronger than in The Sun, while the quality of the background synthesis visibly begins to break down at this level. Tough nut to crack, but with good results. Thumbs up. A detailed comparison with Arcturus is in the pipeline. A new domain migration of the DB server is also needed. Tea-guzzling stuff.

December 2007

The log(gf)-values of 1178 atomic absorption lines in the solar spectrum between 4000 Å and 6800 Å, provided in the VALD-2 database, have now been corrected to best fit the observed solar spectrum. A subset of 660 log(gf)-values measured between 4700 Å and 6800 Å have also been checked with best fits to the spectrum of Procyon. The log(gf)-values of many neutral lines offered in VALD have been improved or had to be deleted from the theoretical spectra in SpectroWeb.

If you utilize the measured log(gf)-values from SpectroWeb for your research, please cite: Lobel A., 2008, SpectroWeb: Oscillator Strength Measurements of Atomic Absorption Lines in the Sun and Procyon. Journal of Physics: Conference Series, Volume 130, Issue 1, pp. 012015. See ADS and the PDF . A concise description of the SpectroWeb database implementation is provided in: Lobel A. 2007, in "The Ultraviolet Universe: Stars from Birth to Death", 26th meeting of the IAU, Editorial Complutense Univ. of Madrid, ed. A. Gomez de Castro and M. Barstow, 167, Aug 2006, Prague, Czech Republic. See ADS and the PDF. Thanks.

January 2007

Internet Explorer 7 browser users please change the 'Navigate sub-frames accoss different domains' setting in IE7 to Enable. Change it under your browser Tools tab -> Internet Options -> Costum level button -> scroll down the Settings list -> click Enable. The setting is enabled in IE6 but appears to have been disabled in IE7. It must be enabled to load the linelists in the same sub-frames.