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

This announcement solicits proposals for observations to be carried out as part of the CHEOPS Guest Observers Programme in the period from 1 July 2022 to 24 September 2023 (inclusive)

Milestones

Release of AO-3: call for Phase I observing proposals          15 February 2022

Deadline for submission of Phase I observing proposals       15 March 2022 (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 be possible to start observations a few days earlier, however this cannot be guaranteed

Important Notes:

Prospective observers are requested 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 are also provided. You are 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 must be submitted via the Phase I Proposal Handling Tool which is accessed via the link given in the Tools and Supporting Manuals section of this webpage. Submission requires the use of a Cosmos Website ID together with membership of the CHEOPS Guest Observers Programme Group. This is also required to download the software for the Scheduling Feasibility Checker, which is one of the tools needed to prepare proposals (see below) and also to download simulated CHEOPS data. To request credentials and group membership please follow the instructions at the following link:  https://www.cosmos.esa.int/web/cheops-guest-observers-programme/register

         We recommend that you get an ID/register as soon as possible.

• A Frequently Asked Questions (FAQ) page will be maintained throughout the period covered by the call. This may be consulted at this link. 
• Notifications of any issues/updates to Call material will be published on the page at this link - you are recommended to check this page regularly during the period that the AO is open
• It is important to appreciate that, due to the nature of the science that CHEOPS will address, the majority of CHEOPS observations will be time critical. These can be difficult to schedule, and in some cases it may not be possible even if a target/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. You are advised not to leave proposal preparation to the very last moment, as it may take a couple of days to answer your questions.

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

Key Documentation:

• Announcement of Opportunity (AO-3) - invitation to apply from the Director of Science
• AO-3 Policies and Procedures - please read carefully through this document, as it contains essential information relevant to the AO
• CHEOPS Observers Manual
• In-orbit updates - links to presentations detailing CHEOPS performances, "tips" from the CHEOPS Science Team and systematics in CHEOPS data 

Is CHEOPS for you?

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

Tools and supporting manuals:

A number of tools and documents are available to help you with your proposal preparation.

• Phase I Proposal Handling Tool (proposal submission) and a csv-formatted file that may be used for the upload of multiple targets
• Templates for the Scientific Justification and Technical Justification and Implementation documents
• CHEOPS Exposure Time Calculator (with online help) -  pdf export of results required for proposal submission
• CHEOPS Scheduling Feasibility Checker, including instructions for installation and giuidelines for use
• CHEOPS Reserved Target List Checker tool (pdf screenshots required for proposal submission)
• CHEOPS Reserved Target List as on 14 February 2022 in csv format  - see note on additional targets at this link, including Alpha Cen.

useful reference data and links    

• In-orbit measurement of the CHEOPS point spread function (also available directly from the CHEOPS archive: REF_APP_WhitePSF)
• Information on the CHEOPS bandpass, including the numerical data (QE curve and optical throughput) required to calculate it
• CHEOPS visibility maps (annual accumulated +1 day (per month) + ascii in a tarball) with README file (note the update relative to that provided in the tarball) - these are also available in pictorial form in the CHEOPS Observers Manual
• Simulated CHEOPS data: raw, level data products and ancilliary files, reports and README file  (pre-launch, included for information)
• Link to the CHEOPS Mission Archive
• Link to the CHEOPS Data page which contains the details of selected CHEOPS data taken during IOC that is already public, simulated data and reference data
• CHEOPS Data Products Defintion Document (DPDD) - detailed description of the content of CHEOPS data products and associated files.

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. Follow tutorials in the detailed documentation here, or find the code and post issues to GitHub
• PIPE - a photometric extraction package for CHEOPS developed by Alexis Brandeker that is complements the official Data Reduction Pipeline (DRP). In contrast to the DRP, which uses aperture photometry on the 200-pixel diamater subarrays, PIPE uses PSF photometry on the 60-pixel diameter imagettes, which are often taken at a higher cadence than the subarrays.

Help:

Please check the Frequently Asked Questions page for common questions as well as details of who to contact in case your question is not answered on the page.