Using spectrogram functions in the Solarsoft environment

Last update: 2009-01-19 5:14 PM

This memo describes how to get started reading and plotting spectrogram data.

1. Install SolarSoft

Go to www.lmsal.com/solarsoft. There, choose the option "pull-down menu interface." Now you can see two menus on the top of the page. From the left menu, choose "Installing & Configuring Solarsoft" and then choose on the right menu "Installing Solarsoft" if you are working on Linux, ore "SolarSoft under Windows" if you are working under Windows.

You have to fill up a form where you will choos which package to install. If you want to use the full capabilities of the software, you need to install at least the ETHZ branch of the tree. You can add as many instruments as you want.

2. Reading spectrogram data

You can read data as follows:

radio_spectro_fits_read, 'yourfile.fits', z, x, y

where yourfile.fits corresponds to the name of the file you want to read in. The data can also be compressed, such that:

radio_spectro_fits_read, 'yourfile.fits.gz', z, x, y

works too.

3. Plotting spectrogram data

Load a color table optionally:

loadct, 5

and then pass the data to the plotter:

spectro_plot, z, x,y , xstyle=3, ystyle=3

Spectro_plot has a lot of options. here the "xstyle" and "ystyle" options are the standard plot options for plot style definitions as defined by idl. spectro_plot acceps all reasonable options deined for the IDL procedure plot.

Now you can also zoom in with xrange and yrange:

spectro_plot, z, x,y , xs=3, ys=3, xrange = '2008-dec-11 09:2' + ['6','7'], yrange = [80,50]

4. Data analysis functions

Constant background subtraction

An automatic background subtraction can be used:

spectro_plot, constbacksub(z, /auto), x,y , xs=3, ys=3, xrange = '2008-dec-11 09:2' + ['6','7'], yrange = [80,50]

Elimination of wrong channels:

To eliminate wrong channels we first do a copy of the original data, as the procedure destroys the eliminated data:

zz = constbacksub( z, /auto ) & xx = x & yy = y

Now we can call the procedure:

elimwrongchannels, zz, xx, yy

and plot the result:

spectro_plot, zz, xx,yy , xs=3, ys=3, xrange = '2008-dec-11 09:2' + ['6','7'], yrange = [80,50]

Color table

You can vary the color table with

xloadct

5. Printing function

To print the file, you first write it into a ps file and then send it to your printer (or include it into other documents etc. )

You start the ppostscript writing with

ps, /color

then you put everything in the file that you want:

spectro_plot, zz, xx,yy , xs=3, ys=3, xrange = '2008-dec-11 09:2' + ['6','7'], yrange = [80,50]

(Note that when ps has been called prior to spectro_plot, nothing will be displayed on the screen). Then you close the file with

psclose

That's it for now!

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André Csillaghy andre.csillaghy@fhnw.ch