Tutorial- lesson 8 - Import UVES spectrum profile

UVES spectra are on the web available spectrum profile acquired by the UVES spectrograph of the European Southern Observatory on the VLT. UVES is a high-resolution spectrograph which covers a range from 3000 to 11000 angströms.

Data comes from a database: UVES Paranal Observatory Project (ESO DDT Program ID 266.D-5655) and are described in a Messenger paper (Bagnulo et al., 2003, Messenger, 114, 10).

You can get the files from http://www.sc.eso.org/santiago/uvespop/bright_stars_uptonow.html

You will then be able to open the .uvs file as a profile in Visual Spec

Only few bright stars are available but covers a large range of spectral type

To display the profile in UVES format, you will have to pick the right format on the web page and download the profile with the correct extension

Which data shall I load ?

On the front list page of the Bright star as linked above, click on the "plot" link

You will get access to the interactive interface which display the profile

Select a wavelength domain - note that spectrum are high resolution - DO NOT download the entire range profile, Vspec will not handle it. (Way too slow...) - Limit the range to 400 angströms, the sampling being of 0.017 angström by pixel, this will give a 23500+ points profile.

Select the format of the output: ascii file

Click on Plot

You will get to a new screen

If you click directly to the link, the ascii table will be displayed in your navigator. To download the file do a right click to select in the pop-up menu the "save the target as..."

A dialog box will prompt you to select the directory where you want to save the file. In the dropdown box of the file type, do not keep "text document" but select "all files"

Edit the extension of the file: replace the .txt by the .uvs

This is important if you do want to edit the file extension after the download. If you do not do this, the file will be saved with a txt extension and not the .uvs that Vspec will use to identify UVES format profile.

Click on "save" - Your file is ready to be read by Vspec after the download

Read the UVES profile with Vspec

Open Vspec - Open a profile - Select the directory where you put the uvs file. In the profile type dropdown box, pick the .uvs extension to display the list of the files.

Select and open the .uvs file you want to display

The profile will be displayed in Visual Spec

Note the sampling coefficient of 0.017 angström per pixel updated. In this example, the H-alpha line is easely recognizable on Arcturus profile. To know more on Arcturus spectrum, click here.

If you save the profile, it will prompt you a dialog box to save it as a .spc file