Full instructions (in case of problems) are here:
http://wiki.x2go.org/doku.php/doc:installation:x2goclient

Easy:

 apt-get install x2goclient

Download from
http://code.x2go.org/releases/binary-win32/x2goclient/releases/4.0.5.0-2015.07.31/
and run x2goclient-4.0.5.0-2015.07.31-setup.exe.

If you don't have it yet first install XQuartz from http://xquartz.macosforge.org/landing/

Type

 echo "*VT100.translations: #override Meta <KeyPress> V: insert-selection(PRIMARY, CUT_BUFFER0) \n" > ~/.Xdefaults 

to the terminal (enables copy&paste).

Then install x2go client from:
http://code.x2go.org/releases/binary-macosx/x2goclient/releases/4.0.5.0/
Select the one that matches your OS version.

Within X2Go, go to the Session menu, choose New session. You'll get a “session preferences” window where you add the login information

Host: tube.utu.fi
Login: ????
SSH port: 42000

Session type: MATE

• Open an XTerm from Applications - System Tools
• To use Scisoft, type scisoft in the terminal
• Image display tools: ds9
• Image display, photometry, astrometry: gaia
• IRAF: mkiraf, cl
• Editors: emacs, vim, pluma
• Browser: firefox
• PDF, PS viewer: atril, evince

Reference of commands shown at the lecture

IRAF homepage
IRAF UserSupport
The Zen of IRAF

Useful IRAF guides:
A beginners guide to using IRAF
http://iraf.noao.edu/iraf/ftp/iraf/docs/spect.ps.Z
http://iraf.noao.edu/iraf/ftp/iraf/docs/ccduser3.ps.Z
http://users.utu.fi/kani/opetus/ht1/irafohje/index.html (In Finnish!)
http://users.utu.fi/kani/opetus/spektriohje/index.html (In Finnish!)