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Job offers : Research contract (H2020_AdG 2020: Project 101019953 ISSP) Feb-Oct 2023 (9 months)

Level : PhD required

Salary : ~3000 euros per month (gross salary, full time, and before the withholding tax)

Type of position : research contract dedicated to the full operation of the fringe tracker SPICA-FT and for the validation and optimization of its performance

Situation : Université Côte d’Azur – Observatoire de la Côte d’Azur - Laboratoire LAGRANGE – Bâtiment Fizeau du Campus Valrose (Nice) & Calern Observatory for remote observing.

Description of Observatoire de la Côte d’Azur

Observatoire de la Côte d’Azur is a French public Center for research in earth sciences and astronomy. With more than 450 persons working at four different locations (Nice Observatory, Université de Nice, Sophia Antipolis, Plateau de Calern), its role is to explore, understand and transfer knowledge about Earth sciences and astronomy, whether in astrophysics, geosciences, or related sciences such as mechanics, signal processing, or optics. OCA is composed of 3 research units (ARTEMIS, GEOAZUR, and LAGRANGE) and 1 support structure (GALILEE). This program will be developed in the Lagrange Laboratory.

The Interferometric Survey of Stellar Parameters (ISSP) ERC-Adv grant, started on 1 Sep 2021 for 5 years, aims at realizing and exploiting an ambitious and homogenous survey of the angular diameters of a thousand stars as faint as magnitude 8 in the visible and as small as 0.2 milliseconds of arc. It takes benefit of the recently commissioned CHARA/SPICA instrument installed on the CHARA Array, Mount Wilson Observatory (USA, CA). The survey is built to address key questions about the relation between planets and stars and to offer to the broader community a unique and primary source of direct information on a representative and large sample of stars all over the HR diagram. The ISSP team is offering a 9-month research contract to support the scientific programs of the survey through the optimization of one of the main critical devices of the instrument: the SPICA-FT fringe tracker.

Description of the position

This position is dedicated to the activities needed to reach a routine operation of SPICA-FT on the CHARA Array within the MIRCx instrument, firstly with the current bulk optics combiner, and secondly with the integrated optics chip that will be installed in July 2023. This routine operation should address the known issues of fringe jumps, the use of reference vectors to account for the internal closure phases, and, if necessary, the correction of the residual dispersion. The operation should be done in H band for servicing the visible instrument SPICA-VIS.

The second aspect of the position will be to establish the performance of SPICA-FT in different spectral resolution and atmospheric conditions, firstly in the H band of its combiner and secondly for the visible combiner.

Main activities

  • Routine operation of SPICA-FT with MIRCx combiner; documentation and user manual. Formation of some CHARA and SPICA staff members to the operation of SPICA-FT.
  • Weekly tests during the CHARA technical nights, in collaboration with the CHARA team.
  • Correction of the known issues on the fringe jumps and optimization of the performance with the minimization of the time loss.
  • Implementation of the reference vectors in the SPICA-FT algorithm and validation of its operation in the different configurations of scopes and combiners.
  • Validation of the fringe relock functionality.
  • Tests and validation of the fringe search algorithm.
  • Preparation of the integration of the PLC component with the installation of the functionalities for doing the P2VM measurement. Use of the Nice testbench to validate the operation of the PLC component.
  • Contribution to the commissioning of the PLC chip in Mt Wilson during the July 2023 run.
  • Study of the performance of SPICA-FT in the different conditions of combiners, spectral resolution, and atmospheric conditions. Reporting and definition of guidelines for the optimization of its operation.


Expertise required in fringe tracking activities, data analysis and simulations of operation. Use and adaptation of optical testbenches, characterization of integrated optics device and compensation of polarization. Good knowledge of the atmospheric dispersion effects and their impact in the fringe tracking activities.


The position assumes some mobility in the United States at Mount Wilson in California for onsite observations. Remote operations will also take place from the Plateau de Calern site of the Côte d  Azur Observatory or from the Fizeau building in Nice.

A few hours of remote operation on SPICA-FT could be organized every week in collaboration with the CHARA Staff. Due to the time zone difference, this corresponds usually to operations very early in the morning in Nice.

The activities will benefit from a large autonomy in the daily schedule, and with the necessary interactions with the software engineer in charge of the SPICA-FT code (Sylvain Rousseau). Fortnightly meetings will be organized with the SPICA/ISSP team in Nice (Denis Mourard, Philippe Bério, Sylvain Rousseau) to follow the progresses and discuss the


The deadline for application is Wednesday 25 Jan 2023, 4pm CET. Interviews will be organized.

Application must be sent by email to denis.mourard@oca.eu. The application should contain a detailed CV, a letter of motivation describing the interest for the position and the skills for the activities that are described.