The AO-3 Call is closed.
You can find the approved programmes and abstracts here.

3rd Announcement of Opportunity (AO-3) for participation in the CHEOPS Guest Observers (GO) Programme

This 3rd Announcement of Opportunity (AO-3) solicited proposals for observations to be carried out as part of the CHEOPS Guest Observers (GO) Programme, with the observation window spanning from 1 July 2022 to 24 September 2023 (inclusive).

Milestones

Opening of AO-3 Call for Phase I observing proposals 15 February 2022
Deadline for submission of Phase I observing proposals 15 March 2022 at 13:00 CET / 12:00 GMT
Meeting of the CHEOPS Time Allocation Committee 11–13 May 2022
Announcement of award of observing time on CHEOPS By 25 May 2022
Preparation of Phase II inputs 1–24 June 2022
Start of observations of AO-3 Programmes 1 July 2022*

* It may have been possible to start observations a few days earlier, although this could not be guaranteed.

Important Notes

Prospective observers were asked to take note of the following points:

  • The Policies and Procedures document is the definitive document for the AO. As the name suggests, this details all the policies and procedures relevant to the AO. It contains details of the observing constraints applicable to CHEOPS, as well as a detailed description of the required contents of observing proposals. Information about the tools and documents available to support observers in their proposal preparation and submission is also provided. Observers were very strongly advised to read through the document carefully before starting proposal preparation. The document can be found in the Key Documentation section of this webpage.
  • All proposals had to be submitted via the Phase I Proposal Handling Tool, which was accessed via the link given in the Tools and Supporting Manuals section of this webpage. Submission required the use of a Cosmos Website ID together with membership of the CHEOPS Guest Observers Programme Group. This was also required to download the software for the Scheduling Feasibility Checker, which was one of the tools needed to prepare proposals, and also to download simulated CHEOPS data. To request credentials and group membership, users had to follow the instructions at the following link: https://www.cosmos.esa.int/web/cheops-guest-observers-programme/register
  • Users were recommended to get an ID and register as soon as possible.
  • A Frequently Asked Questions (FAQ) page was maintained throughout the period covered by the call. This may be consulted at this link.
  • Notifications of any issues or updates to Call material were published on the AO-3 updates webpage.
  • It is important to appreciate that, due to the nature of the science that CHEOPS addresses, the majority of CHEOPS observations are time-critical. These can be difficult to schedule, and in some cases it may not be possible to carry them out even if a target or proposal is awarded observing time and is considered to be high-priority science.
  • CHEOPS is a small mission, with a correspondingly small team to support Guest Observers. Observers are encouraged not to leave proposal preparation to the very last moment, as it may take a couple of days to answer questions.

Updates

  • 7 March 2022: An important update to the Scheduling Feasibility Checker input files was detailed on the AO-3 updates webpage as well as on the dedicated webpage for the tool.
  • 9 March 2022: A clarification on the reserved status of Alpha Cen A/B was detailed on the AO-3 updates webpage.

Key Documentation

Is CHEOPS for you?

  • Two presentations introducing the CHEOPS mission and its capabilities are available at this link.

Tools and supporting manuals

A number of tools and documents were available to help users with their proposal preparation.

Useful reference data and links

User-contributed tools/aids

Below are links to tools that have been developed by members of the CHEOPS Science Team and the CHEOPS Consortium. These are shared for use at the user's own risk, with caveats and warnings that are detailed in the individual documents.

  • A tool to generate XML files for input to the CHEOPS Scheduling Feasibility Checker, based on a table of data for multiple observing requests provided by the user
  • pycheops - a python package developed by members of the CHEOPS Science Team for the analysis of CHEOPS light curves
  • linea - an open source, open development Python package for fast, linear detrending of CHEOPS photometry, by Brett Morris. The code and issue tracker are available on GitHub.
  • PIPE - a photometric extraction package for CHEOPS developed by Alexis Brandeker that complements the official Data Reduction Pipeline (DRP). In contrast to the DRP, which uses aperture photometry on the 200-pixel diameter subarrays, PIPE uses PSF photometry on the 60-pixel diameter imagettes, which are often taken at a higher cadence than the subarrays.
Questions about CHEOPS or the GO Programme? Please email cheops-support@cosmos.esa.int and we will be happy to help!
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