The MICADO atmospheric dispersion corrector: optomechanical design, expected performance and calibration techniques

Ground-based and Airborne Instrumentation for Astronomy IX, vol. 9909, pp. 105

Abstract

The differential refraction of light passing through the atmosphere can have a severe impact on image quality if no atmospheric dispersion corrector (ADC) is used. For the Extremely Large Telescope (ELT) this holds true up into the infrared. MICADO, the near-infrared imaging camera for the ELT, will employ a cryogenic ADC consisting of two counter-rotating Amici prisms with diameters of 125 mm. The mechanism will reduce the atmospheric dispersion to below 2.5 milli arcseconds (mas), with a set goal of 1 mas. In this report, we provide an overview of the current status of the ADC in development for MICADO. We summarise the optomechanical design and discuss how the cryogenic environment impacts the performance. We will also discuss our plan to use a diffraction mask in the cold pupil to calibrate and validate the performance, once the instrument is fully integrated.

Authors 8

1. Joost A. van den Born

   University of Groningen · Netherlands Institute for Radio Astronomy

   Affiliation as printed

   NOVA Optical IR Instrumentation Group, ASTRON (Netherlands)

   Univ. of Groningen (Netherlands)

2. Rick Romp

   Netherlands Institute for Radio Astronomy

   Affiliation as printed

   NOVA Optical IR Instrumentation Group, ASTRON (Netherlands)

3. Annemieke W. Janssen

   Netherlands Institute for Radio Astronomy

   Affiliation as printed

   NOVA Optical IR Instrumentation Group at ASTRON (Netherlands)

4. Ramón Navarro

   Netherlands Institute for Radio Astronomy

   Affiliation as printed

   NOVA Optical IR Instrumentation Group at ASTRON (Netherlands)

5. Willem Jellema Aachen SRON Netherlands Institute for Space Research

   Space Research Organisation Netherlands

   Affiliation as printed

   Kapteyn Astronomical Institute (Netherlands)

   SRON Netherlands Institute for Space Research (Netherlands)

6. Eline Tolstoy
   Affiliation as printed

   Kapteyn Astronomical Institute (Netherlands)

7. Bayu Jayawardhana

   University of Groningen

   Affiliation as printed

   Univ. of Groningen (Netherlands)

8. Michael Hartl

   Max Planck Institute for Extraterrestrial Physics

   Affiliation as printed

   Max-Planck-Institut für extraterrestrische Physik (Germany)