Instructions for Visiting Astronomers

Welcome and good luck observing with VISIR! This page gives some general information on how to prepare for your visitor-mode observations. For any remaining questions regarding your visitor-mode run, you may contact us at the ESO Operations Helpdesk, or in specific cases by e-mail at

One month before your scheduled run

Please check the telescope allocation schedule to ensure that your run has been correctly scheduled. Independently of this, you should have received the announcement of your time allocation, available at the User Portal using your personal ID and password (if you have not received this webletter or the ID, please contact the ESO Operations Helpdesk). This message contains important information about your run and the related logistics. In particular, you have to fill the travel information if you have not already done so. You are also invited to consult the Instructions for Visiting Astronomers, as well as the documentation available on the Paranal Science Operations Web Page, in particular the section for Visiting Astronomers.

Less than 30 days to your arrival on Paranal

It will be beneficial to start with the observation preparations:

  • Read the User Manual
  • Familiarize yourself with the OB preparation tool p2 at
  • Make your OBs in p2:
  • Be able use the ETC to estimate the exposure time
  • Have a defined observing strategy:
    • Which observation templates do you plan to use, in which order, and which instrumental set-up will give you the best outcome?
    • Do you need special calibrators? We have many OBs for normal standard stars and day calibrations ready for use, but if you have special requirements, you should prepare these too.
    • Prepare your list of targets: remember that you can only observe those targets listed in your Phase 1 proposal. If you wish to change targets, or if you need additional targets, you will have to request them. Remember that we often have strong wind from the North (meaning that you will have to observe south of DEC = -24.5°), and backup targets might also be needed in case of poor seeing or thin clouds. ADDITIONAL AND BACKUP TARGETS, AS WELL AS SET-UP CHANGES must be requested and approved in advance using this specific procedure.

When arriving on Paranal

You will normally have 2 nights in order to finalize your observation strategy and your observation blocks together with your support astronomer.

During your Observations

The Observatory has prepared OBs of standard stars (Cohen standards) for normal imaging and low resolution spectroscopy. They can be used at anytime for a visitor run and if needed can be modified online at the console (e.g. the filter selection). Calibrator OBs for all other modes need to be prepared by yourself.

Where to find your data?

Typically, the data will arrive to the ESO archive within a few minutes and can then be downloaded from there. Burst Mode data and data obtained without half cycle summing may take longer to arrive in the archive due to their size.

Visiting astronomers can also work with the astuser2 account on wgsoff2. The data is sorted into directories named by the date with the data taken from 12:00 to 11:59 UT, e.g.:


The science and calibration data of VISIR are automatically reduced by the pipeline. Pipeline-reduced data will not be available in the ESO data archive; the user is welcome to copy them to their computers during or immediately after the observations.

After your Observations

Please complete the end-of-mission report when you are invited to do so after your observing run is completed.