New interferometric technique for piston measurement and phasing of segmented mirrors

• Autores: Agustí Pintó
• Directores de la Tesis: Ferran Laguarta Bertran (dir. tes.)
• Lectura: En la Universitat Politècnica de Catalunya (UPC) ( España ) en 2002
• Idioma: inglés
• Tribunal Calificador de la Tesis: Enrique García-Berro Montilla (presid.), Josep Arasa i Martí (secret.), Jordi Isern i Vilaboy (voc.), Eusebio Bernabeu Martínez (voc.), Martín Pedro Ramón Álvarez (voc.)
• Materias:
  • Física
    • Óptica
  • Ciencias tecnológicas
    • Tecnología de la instrumentación
      • Instrumentos ópticos
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• Resumen

  • Present trends in the design of ground-based telescopes point towards the use of segmented primary mirrors. A major problem in this type of mirror is the achievement of proper segment positioning, as they have to be aligned with an accuracy of the order of a fraction of a wavelength for near-diffraction-limit telescope performance in the infrared. In this paper we present a new interferometric technique applied to the measurement of segment vertical misalignment (piston error) in segmented mirrors. The instrument is based on a high-aperture Michelson interferometer using a broadband light spectrum. The main innovation introduced in this instrument is the use of a novel optical fibre illumination technique that allows the system to measure piston error during the daytime with an uncertainty of 5 nm in a 30 µm range. A detailed description of the light spectrum, expected interferograms and piston extraction algorithms is presented here.