1st Announcement of Opportunity (AO-1)

For Participation in the PLATO Guest Observers (GO) Programme

This 1st Announcement of Opportunity (AO‑1) marks the beginning of PLATO’s Guest Observers (GO) Programme. It offers the community access to space‑based, ultra‑high‑precision photometry for scientific investigations that are complementary to the mission’s core objectives. The AO‑1 Call opens on 7 April 2026 at 12:00 noon CEST and closes on 21 May 2026 at 12:00 noon CEST. Awards of observing time are expected by the end of August 2026, enabling successful proposers to prepare timely follow‑up proposals for other space‑ and ground‑based facilities. The associated observing cycle will cover the first two years of PLATO’s nominal operations. For example, assuming a launch in January 2027, this cycle would run approximately from April 2027 to April 2029.

Milestones

Where to start & important notes

1. Read the Policies & Procedures document carefully. It is the definitive reference for all AO Call requirements, including the PLATO science programme, available observing time, operational constraints, proposal structure, and the tools supporting proposal preparation.
2. Familiarise yourself with the Mission Handbook. This document serves as the prime reference for scientists preparing PLATO observations, intorducing the spacecraft, payload, observing strategy, and data products.
3. Register early for the PLATO GO system. A valid ESA Cosmos account and registration in the GO Programme are required for proposal submission.
4. Consult the PLATO Input Catalogue (PIC) via the PLATO ArXiv (PAX). These tools provide essential information on available targets, contaminants, and feasibility parameters required for proposal preparation.
5. Begin preparation early, consult the webpage examples and FAQ, and leverage the proposal software. Support resources are limited, and late questions may not be answered in time. Early preparation reduces the risk of missing requirements. Browse the webpages, particularly the proposal submission and FAQ sections, which provide many user-friendly illustrations of the formal material presented in the documents. Leverage the ESA Science Campaign Handling System (CHS) and built-in PLATO Call for Proposals Toolset (CfP) for target checks, noise-to-signal estimates, and much more.
6. Ensure full dual-anonymity. All proposal material, including file names, must be fully anonymous. Non‑compliant proposals will be automatically rejected on formal grounds.
7. Submit your proposal via the official proposal software. Proposal upload and access to selected tools require a Cosmos login and GO Programme membership, and will use the CHS & CfP software.

• Note: An award of observing time does not guarantee execution. Operational constraints, scheduling limitations, and unforeseen events may affect feasibility, even for high‑priority programmes.
• Note: Updates related to the AO Call will be posted at the bottom of this webpage.

Key Documentation

• 1st Announcement of Opportunity (AO-1) - invitation letter by ESA's Director of Science
• Policies and Procedures
• Mission Handbook

Tools and Material

• Proposal Software
  • Campaign Handling System (CHS) & Call for Proposal Toolkit (CfP) >> 
  • CHS & CfP User Manual
• Data
  • PLATO ArXiv (PAX) >>
  • Product Definition Document

Additional references

• PLATO Mission Paper
  • Rauer et al., (2025, Exp. Astron., 59, 3)
• PLATO Input Catalogue (PIC)
  • LOPS2 PIC2.2.0.1 Release Notes
  • LOPS2 PIC2.2.0.1 PIC Data Definition Document
  • Montalto et al. (2026, preprint) - tPIC
  • Nascimbeni et al. (2026, preprint) - tPIC Prime Sample
  • Prisinzano et al. (2026, A&A, 706, A207) - tPIC P4 Sample
  • Zwintz et al. (2026, preprint) - scvPIC
  • Heller et al. (2026, preprint) - cPIC and fgPIC

PLATO Helpdesk

If you have any questions, please carefully consult the documentation referenced above. If you cannot find the information you need, our PLATO Helpdesk will be happy to help.

Updates

No updates yet.

Happy proposing!