Development of a calibration tool generating sources for optical alignment of instruments

The goal of the project is to design and integrate a calibration tool which projects sources at given distances and use it for the calibration of an alignment telescope. A small “side project” is associated in case time allows.

At ESO alignment telescopes (or sighting telescope) are used to perform alignment of simple to complex optical systems like for instance VLT or ELT instruments. To optimise the use of this tool we want to be able to calibrate its focusing actuator for specific environmental conditions, thus the need of having a stable projector able to re-image sources at known distances.

In practice, the work is divided in 2 main phases and a small side project:

  • Opto-mechanical design and integration of the projector head. The focusing mechanism needs to be motorized with an Arduino controller and include a display, temperature sensor on the projector tube and limit switch(es). The projector itself should then be tested optically and calibrated in focusing distance, if possible in different environmental conditions.
  • Integration and test of a custom alignment telescope according to an existing design. The telescope would then be calibrated with the projector. For this phase, the student would be assisted by an ESO engineer
  • As “side” project : develop a small rotating tool, also based on an Arduino controller, to rotate spherically mounted retroreflector (SMR) targets onto themselves for a small SMR test bench.

The integration and tests would be done in our optical laboratory and using its facilities under the supervision of the optical alignment and metrology group.

Knowledge in optics, Arduino programming, CAD design (inventor), basic optical alignment knowledge and an ability to perform practical work in laboratories in a semi-autonomous way, are the skills required for this project.

The student will have the opportunity to develop opto-mechanical skills as well as different alignment techniques and knowledge in astronomical instrumentation. He will also have the opportunity to use a Laser Tracker and learn the associated Spatial Analyzer SW.


Supervisors:  Sebastien Tordo, Stéphane Guisard