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Remote Use

From SharedSkies

The computers that control the telescopes are accessible for remote login by authorized users. Because the user interfaces require the transport of graphical data that is frequently updated, the usual approach to use secure shell with X windows does not work well outside the observatory network. Instead, we offer VNC on the observatory control computer and allow the remote user to control the observatory system by using a VNC viewer on their own desktop. VNC efficiently buffers the graphical data and compensates for latency in transmission.

The remote user must have the TightVNC jviewer installed. To obtain and install a copy go to

www.tightvnc.com

Click "Java Viewer", and you will be taken to an option to download from

www.tightvnc.com/download.php

Follow their instructions install the viewer on your system.

If you are using Apple IoS or Linux, then you already have software to display an X terminal. If you are a Windows users, then install MabaXterm to provide a convenient local Unix command prompt on Windows:

mobaxterm.mobatek.net/

Finally, if you are not inside the University's firewall you need an account on the VPN or an account on one of the systems that allows remote secure shell (SSH) login. Start a console session on your computer and connect to a "computer" on campus for which you have an account:

 ssh -L 5901:localhost:5901 user@computer.physics.louisville.edu

would be an example of the login required, where "user" is your user name, and "computer" is the system for which you have an account and authorization. Once you are connected to that computer you may continue to connect to the observatory telescope computer. Each telescope has its own controller, so you would make the connection this way;

 ssh -L 5901:localhost:5901 user@controller.astro.louisville.edu

where "controller" is the computer running that telescope. This process tunnels port 5901 from the telescope controller to your desktop through an encrypted secure connection.

On the controller, start the vncserver with the command line

 vncserver :1

to use the first server (and port 5901), or similarly for the other servers which use sequential port numbers.

On your desktop start the TightVNC jviewer set to localhost on port 5901. With that, the remote desktop will appear within the TightVNC application on your computer.

When you are finished, disconnect your local TightVNC. On the controller kill all the vncservers you have started with commands such as

 vncserver -kill :1

and exit from the SSH connections you established to the controller and the campus access point.