Applying for Observing Time

Telescope time with ESO telescopes at the La Silla Paranal Observatory is allocated twice a year in periods of six months. Allocation periods run from 1 October through 31 March, and from 1 April through 30 September. Applications for observing time must be submitted using the web-based p1 interface accessible at  

The Call for Proposals describes the conditions under which observing time is offered with ESO telescopes at the La Silla and Paranal sites of the Observatory. The document is available in electronic form via this Web page.

The deadline for Period 114 (1 October 2024 - March 2025) is:

21 March, 2024

(12:00 noon, Central European Time)

Applications for observing time with ESO Telescopes have to be prepared using the p1 web system.
It is the PI's responsibility to resolve any submission problems well before the deadline. Please note that ESO cannot provide support beyond 11:00 CET on the day of the deadline.

Please note that Distributed Peer Review applies in Period 114.
For more details, please see:

Mandatory update of the ESO User Portal profiles for science users
Please see the announcement on the request to update user profiles on the ESO User Portal. Users failing to do so will not be able to submit a proposal as PI and/or as CoI.



Call for Proposals for Period 114

Applications may be submitted for the usage of the telescopes, instruments and instrument modes specified in the Call for Proposals.

  • Period 114 Call for Proposals

  • Useful links for Period 114
    Links to technical information about ESO facilities; foreseen changes in the performance of the offered instruments and useful information for the preparation of ESO proposals for the current call for proposals.

  • Late Breaking News
    Please check this page regularly. It will contain information about the Call for Proposals that becomes available after the release.


Applications for observing time on ESO telescopes must be submitted by the respective deadline (end of March and end of September) using the Web-based p1 interface accessible at

This is accessible via your User Portal credentials. The Principal Investigator and all Co-Investigators must have an ESO User Portal account. You can register at Please refer also to the instructions given in the Call for Proposals.

In case you need practical assistance to prepare your proposal, including technical requirements of the planned observations, please contact ESO via the ESO Science Operations  Helpdesk .

The above platform can be used for all questions and comments related to the proposal submission (how to prepare your proposal, what error messages really mean, etc.), as well as more general questions concerning instrument performance, Observatory policy, etc.