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Gemini guide star selection and URL TOO triggering

Project description


This repository provides a python example of using the Gemini Observatory API for triggering template observations that are On Hold. Details of the ToO activation process are given here. The document urltoo_readme.txt give more details about the API.

The example triggering script is but most of the code is for selecting a guide star. The triggering API does not support the new automated guide star selection features in the Observing Tool. The script mimics these features and should find an appropriate guide star if one is available in the UCAC4 catalog. It can also display the guide star candidates and the wavefront sensor field of view on a DDS image of the field.

Gsselect also has a 'find' position angle (PA) feature that we never implemented in the OT. This will pick the best guide star available and set the PA so that it is reachable. This is useful with the GMOS and F2 OIWFS guide probes if the PA is unimportant.


The scripts require a standard Python distribution that includes numpy (at least 1.15.4), matplotlib, astropy, and requests.

Then install the scripts by downloading and unpacking the zip file or use git, e.g.

git clone

The gsselect guide star selection routines can also be installed as a pip package with

pip install gsselect


Authentication for the trigger requires a 'user key' for the Observing Tool that is associated with an email address that is included in the active program. See this page for more information on user keys and how to obtain one.

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