Virtual Network Computing (VNC) is a graphical desktop sharing system that uses the Remote Frame Buffer protocol (RFB) to remotely control another computer. It transmits the keyboard and mouse events from one computer to another, relaying the graphical screen updates back in the other direction, over a network.
VNC can be used on every telescope controlling computer, but it is preferred over SSH on m16.konkoly.hu, the controlling system of OCELOT.
In order to use VNC to log in a computer, the vncserver has to be installed on the target computer. If it is not, notify someone who has admin rights on the computer in question, typically the head of technical department, the computer admin of the CSFK or a support astronomer. The vncserver should be run in screen (see also Usage of the screen program) in order to prevent the program from halting when logging out. The user should also specify an instance ("screen") number. This number on m16.konkoly.hu is conventionally 42. These can be executed with the command
$vncserver :42
A password has to be defined for the vncserver as well. This password is usually stored in ~/.vnc/passwd and can be changed with vncpasswd. Note that the password on m16.konkoly.hu is already defined, do not change it!
To connect to a vncserver instance, a client can be used, e.g. XTightVNC, RealVNC, etc. This has to be installed on the observer's computer. Here's an example of connecting the vncserver running on m16.konkoly.hu with xvncviewer:
xvncviewer -bgr233 -via root@m16 :42