Applying for Observing Time

Telescope time for ESO telescopes at the La Silla Paranal Observatory is allocated twice a year in periods of 6 months. Allocation periods run from 1 October through 31 March, and from 1 April through 30 September. Applications for observing time on ESO telescopes may only be submitted electronically, and only using the ESOFORM proposal submission package obtained from this Web page.

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

The deadline for Period 101 (1 April - 30 September 2018) is:


28 September, 2017

(12:00 noon, Central European Summer Time)

Applications for observation time for the ESO Telescopes have to be prepared using the ESOFORM package, and uploaded via the web. More details are given below. In order to submit proposals for ESO telescopes the ESOFORM package for cycle 101A should be downloaded.

Please note that conformity checks are performed at proposal submission time. Hence, proposers should follow the instructions given in the ESOFORM user's manual and to verify a "skeleton" version of their proposal well before the deadline. It is the PI's responsibility to resolve any LaTeX, formatting, figure upload or configuration problems well before the deadline. Please note that ESO cannot provide support beyond 11:00 CEST on the day of the deadline.


Call for Proposals for Period 101

Applications may be submitted for the usage of the telescopes, instruments and instrument modes specified in the Call for Proposals for Period 101.

  • Period 101 Call for Proposals
    This document has been shortened to focus mainly on policy and proposal preparation information.
  • Useful links for Period 101
    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 this page check regulary. It will contain information about the Call for Proposals that becomes available after the release.

Proposal Submission

Applications for observation time at ESO Telescopes have to be prepared using only the latest ESOFORM package. Please read the ESOFORM Users' Manual for details. You can submit your proposal to ESO via a web upload at:

Please note that since Period 96 the seeing is defined as the seeing in the V band at zenith. See the Phase 2 Observing conditions page for more information.

In case you need practical assistance from ESO to prepare your proposal, please send an email to

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