Scheduling Feasibility Checker (SFC)

The CHEOPS Scheduling Feasibility Checker (SFC) tool allows you to check whether and when a target is visible to the instrument. You can also assess the impact that interruptions due to the satellite's passage through the South Atlantic Anomaly and Earth Occultations have on the target visibility. Finally, the SFC estimates the CHEOPS Observing Efficiency for the target, i.e. the fraction of time the instrument can collect photons from the target within the visibility window. The SFC is designed to run on your own computer in a virtual machine as a virtual image. The latest version is image 9 (released March 2023). You can find instructions on how to download, install, and use the virtual machine and tool by clicking on the following buttons:



  • You can download the two template observation request files that are included in the VirtualBox image here and here.
  • Some users experienced difficulties using the SFC with UBUNTU OS. You can find suggested solutions here.
  • VirtualBox currently does not support the Apple M1 chipset. For now, there is no remedy to this problem other than using different hardware.
  • To view possible visits to the very end of the nominal mission, please change the "Validity_Stop" date in the HTML files used by the SFC to specify details of observation requests to UTC=2023-09-25T00:00:00 (this is necessary for both time-critical and non-time critical observations).
  • Pycheops' function make_xml_files - a community-developed tool to generate XML files for input to the SFC, based on a data table for multiple observing requests provided by the user. You may use this tool at your own risk, with caveats and warnings detailed in the documentation.

Change log:

  • Image 9 (released March 2023): You can now predict observing windows up to December 2028. The download guide, installation guide, and user guide were updated to reflect these changes. This SFC version includes a small but important change in the format of the observation request files: the two parameters that were previously called Target_Vmagnitude and Target_Vmagnitude_Error are now called Target_Magnitude and Target_Magnitude_Error. It is not possible to ingest files that follow the old format in new SFC version.
  • Image 8 (released November 2022): You can now predict observing windows up to July 2028. The download guide, installation guide, and user guide were updated to reflect these changes.


Questions about CHEOPS or the GO Programme? Please email cheops-support at and we will be happy to help!
This website was last updated on 26 February 2024.