LOEM Instructions xx


The La Silla Observatory Eavesdropping Mode (LOEM) is a web-based application for viewing instrument panels on La Silla. As it is entirely web based, no software installation is necessary, apart from a modern, up-to-date browser. Note that LOEM only offers viewing function - no mouse control is allowed to the remote panels. You will be expected to edit, modify and queue your OBs in parallel with the p2ls tool and monitor weather conditions with the ASM.


  • A modern browser like Firefox or Chrome. There has been issues reported with Safari.
  • A reliable internet connection. LOEM has been tested with an average home connection. 

User credentials

Your username and initial password will be given by La Silla staff at the start of your observations; these are different from those for the User Portal.  

Your LOEM account is set up for the approved date and time of the observations. A message "This user account is not currently valid." will appear if you try to enter outside the approved period.

Access rules

Apart from the web authentication, the access is controlled at all times by the La Silla operator. In order to view the relevant panels, a "door" needs to be opened on the La Silla side.

As a security measure, once you have terminated the connection, the "door" on the La Silla side will shut automatically. Re-entry is only possible when the operator reopens the door (which will take a few seconds).

Only one observer is allowed connection at a given time. An error message will appear if you try to connect to an already occupied instrument.

All user activities (entry time, instrument and IP address) are logged. Unauthorised access or suspicious activities will be reported.


  • Establish a voice/video contact with the operator via Teams. You will be given the LOEM credentials.
  • When ready, the operator will enable the connection from the La Silla side, and signal you to enter.
  • Log into LOEM with your credentials.
  • You will be presented with a list of telescope/instruments. Click on the instrument of your run. Your session will start after a few seconds.
    • You may find that the mouse pointer will disappear when moved inside the viewing area. This is the normal behaviour.
    • Currently the right hand screen of the instrument workstation is offered. If you want to view certain panels, ask the operator to drag them into the viewing area.
  • The keystrokes CTRL-ALT-SHIFT (Mac: control+option+shift) will present you with a menu:
    • “username - home" will get you back to the home screen (but the connection is not cut)
    • “username - disconnect” will terminate the remote connection
    • There are also options for zooming in or out.
  • Once disconnected, or if you experience dropouts, the "door" on La Silla will shut automatically. If you try to connect again, a message will appear ("Connection Error. The remote desktop server encountered an error and has closed the connection"). You will need to tell the operator to re-enable the connection on their side again.