p2 - Finding Charts and Ephemeris 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, OBs prepared for execution on 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, limited in size to a maximum of 1 Mbyte, and follow a set of generic requirements that are described here. Up to 5 Finding charts can be added to any OB.


To attach or generate finding charts to an OB in p2, please select the Finding Charts tab from the OB view. You will be given the option either to 'upload custom-made finding charts' or to 'generate finding charts' by simply clicking the respective button. The finding chart generation service whithin p2, called p2fc, is offered as of P103 for most VLT/VLTI instruments. Please see the dedicated p2fc webpage for further details.


Important: As the p2fc finding chart generation within p2 is a non-interactive automatic process, please take a careful look at the created finding charts and check if all the information you want the finding chart to convey is clearly shown (!)   

In general, any software that produces JPEG files of sufficient quality and compliant with the general equirements can be used to produce finding charts. ESO distributes the Skycat- based finding chart tool, which provides another user-friendly interface for creating Service Mode compliant finding charts in JPEG format starting from FITS files. This tool is distributed as part of the FIMS package, but also available as a stand-alone package, and can be used also for the preparation of finding charts for any instrument. The finding charts created with the FC plugin for Skycat need to be uploaded to the respective OBs in p2.  

Please notice that ESO-compliant Finding Charts for a limited number of instruments can also be made using the python module fcmaker, an api user-contributed software.  Fcmaker relies on the p2api to easily interact with the p2 database - more information about the p2api can be found here.

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 Moving Targets Procedures page.


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