2nd Announcement of Opportunity (AO-2) for participation in the CHEOPS Guest Observers (GO) Programme

This 2nd Announcement of Opportunity (AO-2) solicited proposals for observations to be carried out as part of the CHEOPS Guest Observers (GO) Programme, with the observation window spanning from 26 March 2021 to 25 March 2022 (inclusive).

Milestones

Important Notes

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

• All proposals had to be submitted via the Phase I Proposal Handling Tool. Submission required the use of a Cosmos Website ID together with membership of the CHEOPS Guest Observers Programme Group. Registration was 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. Requests for both IDs and group membership had to be made by following 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 early during the call.
• The minimum time that could be requested was 1 orbit per target.
• 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 is awarded observing time and is considered to be high priority.
• All tools and documentation, with the exception of the ESA Phase I Proposal Handling Tool, were provided by the CHEOPS Consortium and were the same as those used by the Science Team to prepare the Guaranteed Time Observing Programme.
• 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.
• A Frequently Asked Questions (FAQ) page was maintained throughout the call and throughout Year 2 of CHEOPS. This may be consulted at this link.
• Notifications of any issues or updates to Call material were published on the AO-2 updates webpage.

Updates

• 24 November 2020: Important updates to the proposal templates were published on the proposal templates webpage.

Key Documentation

• Announcement of Opportunity (AO-2) - invitation letter by the Director of Science
• Policies and Procedures (AO-2)
• CHEOPS Observers Manual
• Illustration of CHEOPS Science Performance

Tools and supporting manuals

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

• Phase I Proposal Handling Tool (PHT1) - online tool used for proposal submission, together with a csv-formatted file that may be used for the upload of multiple targets
• Proposal Templates - templates for the Scientific Justification and Technical Justification and Implementation documents
• CHEOPS Exposure Time Calculator - with online help
• CHEOPS Scheduling Feasibility Checker - including installation instructions and user guidelines
• CHEOPS Reserved Target List Checker
• CHEOPS Reserved Target List as of 4 November 2020 in csv format

Useful presentations, reference data and links

• CHEOPS point spread function (PSF) - in-orbit measurements; also available directly from the CHEOPS archive as REF_APP_WhitePSF
• CHEOPS QE curve - also available directly from the CHEOPS archive as REF_APP_QE
• CHEOPS optical throughput - Beginning of Life; also available directly from the CHEOPS archive as REF_APP_Throughput-BeginOfLife
• CHEOPS visibility maps - annual accumulated maps, monthly maps, and ascii files, with an updated README file
• Simulated CHEOPS data - raw and level data products, ancillary files, reports, and a README file (pre-launch, included for information)
• CHEOPS Mission Archive
• CHEOPS Data webpage - details of selected CHEOPS data taken during IOC that is already public, simulated data, and reference data
• CHEOPS Data Products Definition Document (DPDD)

User-contributed tools/aids

Below are links to documentation and 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.