p2 - Finding Charts and Ephemeridis file

Finding charts and ephemeris files for Service Mode runs must be submitted to the ESO Database as a part of the OBs to which they belong. Visitor Mode observers may also use the finding chart and ephemeris file facilities in p2 for convenience during their observing runs.

Exceptionally, public surveys with VISTA and VST do not require finding charts.

Generic finding chart requirements

Finding charts for use in Service Mode must be prepared in JPEG format following a set of generic requirements that are described under


There are also instrument-dependent requirements on the finding charts that can be found by selecting the instrument from the pull-down instrument selector menu in the upper right of this web page. Any software that produces JPEG files of sufficient quality and compliant with the requirements indicated above can be used to produce finding charts. In particular, ESO distributes the Skycat- based finding chart tool, which provides a user-friendly interface for easily creating Service Mode compliant finding charts in JPEG format starting from FITS files. This tool is distributed as part of the FIMS, VMMPS, and GUIDECAM packages, but can be used also for the preparation of finding charts for any instrument. It can be found under


For HAWK-I, MUSE and VISIR users are encouraged to use the unified GuideCam tool to prepare their Finding Charts.

Please note that the size of the JPEG files that can be submitted as finding charts is limited to a maximum of 1 Mbyte.



Up to 5 Finding charts can be added to any OB by selecting the Finding Chart tab in the OB view.  

Please notice that ESO-compliant Finding Chart for a limited number of instruments can also be made using the python module fcmaker. Please see the paper describing the tool at the following page while a full description of the module can be found here. Please also notice that fcmaker relies on the p2api to easily interact with the p2 database. Plese find here more informations about the p2api.

Users are kindly asked to test the API functionalities by programming against the p2 Demo server before using their script on the Phase 2 approved run. 

Generic Ephemeris file requirements

Ephemeris files are plain ASCII files containing the positions and differential motions of moving targets at given dates. The detailed requirements on the contents of ephemeris files for Service Mode runs can be found under



Once created, an Ephemeris file can be added to any OB by selecting the Ephemeris tab in the OB view.