All information on how to observe with ESO telescopes is provided here. The link provides all the required information on how to prepare proposals for ESO’s telescopes, information for visiting astronomers as well as information on observing programmes, scheduling, Target of Opportunity (ToO) proposals, Large Programmes and Director’s Discretionary Time (DDT) Requests. All ESO data can be accessed via the ESO data archive.


Yes! An ESO User Portal account is essential for accessing all ESO services and observations. This includes submission of proposals to ESO (using the ESOFORM package), accessing the OPC results, submitting Phase 2 observing material, as well as accessing the raw and reduced ESO data and advanced data products (catalogs). Please use the ESO User Portalto create an ESO user account. More information on the ESO User Portal can be found on the ESO User Portal FAQ page.
Proposals for observations at the ESO telescopes are invited twice a year. The P101 Call for proposals can be found here. A direct link to the call for proposals for the Paranal instruments and facilities (VLT/VLTI) can be found here and the call for proposals for the La Silla instrument and facilities can be found here.
Yes. The ESO Call for Proposals provides information on the instruments and facilities offered and their overheads for each period as well as the most recent changes and foreseen changes to the relevant to the current (or forthcoming) period.
Phase 1 includes processes from proposal preparation to scheduling to the final communication to the PI.
Phase 2 includes the observation preparation for ESO telescopes and follow-up of their execution. Service Mode observations are prepared prior to the observing period start (typically deadlines are in the beginning of February and beginning of August). After the Phase 2 observation material is validated and approved, the Service Mode observations are carried out by ESO staff within the period for which the observing programme is scheduled. Data quality is assessed by the observers, who classify the observations accordingly as completed or to be repeated. All data are transferred in near-real time to the ESO archive and users have access to follow-up the status of their observations as well as to download their data. Reduced science data are also made available for those instruments that ESO carries out unsupervised science data reductions. Visitor Mode observation preparation is typically done shortly before the observing run starts and the observers get support from the observatory staff on the mountain.
Phase 3 of preparation, validation and ingestion of science data products for storage in the ESO science archive facility, and subsequent data publication to the scientific community at large. PIs of successful Large Programmes and Public Surveys are committed to carrying out Phase 3. Other contributions are welcome.
Yes, ESO provides ETCs for most instruments. ESO’s ETC can be found here. Note: Users are encouraged to mention the seeing used while calculating the exposure times in the Phase 1, preferably in the ‘Technical Justification’ section of the proposal.
Information on preparation for Phase 2 of observing with ESO can be found here.
For Service Mode observers. Phase 2 observing material must be prepared using the P2PP tool - version 3 (for VLT/VLTI) and P2PP tool - version 2 (for La Silla instruments).
P2PP has a Java Graphical User Interface (GUI). This runs on top of a database which connects to the ESO server and downloads the needed information when required.  Once the proposal information is downloaded to P2PP, users can work on the P2PP even without an internet connection. The P2PP manual (for the VLT/VLTI instruments and La Silla instruments) provides all the information required for successfully completing the Phase 2 preparations.
Note: P2PP can be used in its ‘tutorial mode’ to calculate the overhead and the time required for calibrations for Phase 1, i.e., proposal preparation/submission.
For Visitor Mode and Designated-Visitor Mode observers (exceptions are VIMOS users), ESO’s Phase 2 can be prepared using the web-based application p2 software. In the (near) future p2 will be extended for Service Mode observation preperation as well. 
Please refer to the ESO Phase 2 page for full information.
Yes, ESO observations can be requested in Service Mode. A relatively recent overview of observing modes at ESO telescopes can be found in Marteau et al. (2016), SPIE. Overviews of Service Mode operations and performance metrics can be found in Primas et al. 2014, ESO Messenger; Primas et al. 2016, SPIEand Sterzik et al., 2016, SPIE. Users of Service Mode are usually curious to know how and when their observations would be scheduled. The current algorithms used for scheduling Service Mode observations on Paranal are described in the P2PP3 user manual. This algorithm has evolved from the requirements for preparing and scheduling survey observations that is described in Bierwirth et al. 2010, SPIE, and it includes the more general principles described in an older article by Silva 2001, ESO Messenger.
The main difference is that observations in Visitor Mode are scheduled on a specific night or set of nights, while Service Mode observations from many different programmes are scheduled over a longer period of time. This allows flexible scheduling and observations of the programmes within requested atmospheric constraints depending on current observing conditions. In Service Mode top priority programmes are executed when their observing requirements are met, but if the conditions change, the observer can quickly select another programme that fits well the conditions from the Service Mode pool.
An overview of the Observing Conditions relevant to ESO proposals can be found here.
The following presentation provides and overview of services and tools available to the observers.
The ESO User Support Department runs a helpdesk that provides advices and answers to users’ questions and is contacted via
The following documents explain how to efficiently use ‘bright time’ for your observations:
Patat, F., 2004, Messenger: “Observing During Bright Time: Tips and Tricks
Yes, you are encouraged to monitor the status of your observing run. This can be done through the phase 2 tab in the ESO User Portal. From the ESO User Portal, users can also subscribe to receive night reports via e-mail each time an observation for their programme is executed.
Information on Selecting and Scheduling Observing Programmes at ESO can be found in Patat & Hussain., 2013 as well as in the article on “Growth of Observing Programmes at ESO” by Patat & Hussain, 2012, Messenger. A deeper insight on the OPC process may be gleaned from watching ESOcast 116.
Yes! A PI can delegate the Phase 2/Phase 3 responsibility as well as give proprietary data access rights to a CI. This can be done using the ESO User Portal.
A variety of processed data is available via the ESO science data archive. They are either generated by the community for specific programmes and science goals, or by ESO by using standard data reduction procedures for the entire history of the most popular instrument modes. Extensive documentation is available for each data collection (ESO data releases and ESO data streams). Users should critically evaluate whether the available processed data are suitable for their science goals. As an alternative, ESO makes tools available to process raw data, through which users have full control on the reduction process.
The link to the official ESO data access policy can be found here.
REFLEX, (Freudling et al., 2013, Ballester et al., 2011) is the recommended environment to reduce ESO data. It automatically organizes input files according to their category and runs the entire reduction chain at the push of a button. It supports break points in the reduction sequence to inspect and interact with intermediate and final products and rerun the corresponding step if necessary. Esorex, a command-line utility for running pipeline recipes, and Gasgano, a Java-based data file organize, are also available. The list of available pipelines, and corresponding tutorials can be found here.
The trending of the ESO instruments can be found here.


Access to the ESO archive can be found here. In the archive one can get the Raw data (science, calibrations and acquisition) as well as the Processed data. 
DDT proposals can be submitted at any time. Full details on the nature of DDT proposals and applying for DDT can be found in the ESO DDT page.
Science Verification (SV) programmes are aimed at new instruments for verification of the performance and capability of the instrument. These are Service Mode observations and are ideally ‘demonstration’ proposals (preferably 2 to 5 hours). These proposals should be directly aimed at the new mode of the instrument offered. SV nights are advertised in the ‘Science Newsletter’. They are normally announced before the typical proposal deadlines and are timed to follow-up with the normal calls. Please refer to the ESO SV page for further details.


Yes! ESO has several newsletters that provide the latest news from ESO. The information on the ESO newsletters can be found here.
The ESO Science Newsletter is aimed at the scientific community and provides information on the technical and operational news from ESO. To start receiving the ESO science Newsletter you will need to create an ESO User Portal account.
ESO also has a quarterly journal presenting ESO's activities to the public. This is called ‘The Messenger’. Click here for more information on ‘The Messenger’ and how to subscribe to it.
It is the ESO Telescope Bibliography.  Here, users can query for publications and from the publications, if ESO data is used, the users can reach the raw and processed data used in the publication.
ESO users are encouraged to direct all queries for help to