Heimdallr, Baldr, and Solarstein: designing the next generation of VLTI instruments in the Asgard suite

Adam K. Taras, J. Gordon Robertson, Fatme Allouche, Benjamin Courtney-Barrer, Josh Carter, Fred Crous, Nick Cvetojevic, Michael Ireland, Stephane Lagarde, Frantz Martinache, Grace McGinness, Mamadou N. Diaye, Sylvie Robbe-Dubois, Peter Tuthill

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


High angular resolution imaging is an increasingly important capability in contemporary astrophysics. Of particular relevance to emerging fields such as the characterization of exoplanetary systems, imaging at the required spatial scales and contrast levels results in forbidding challenges in the correction of atmospheric phase errors, which in turn drives demanding requirements for precise wavefront sensing. Asgard is the next-generation instrument suite at the European Southern Observatory’s Very Large Telescope Interferometer (VLTI), targeting advances in sensitivity, spectral resolution, and nulling interferometry. In this paper, we describe the requirements and designs of three core modules: Heimdallr, a beam combiner for fringe tracking, low order wavefront correction, and visibility science; Baldr, a Zernike wavefront sensor to correct high order atmospheric aberrations; and Solarstein, an alignment and calibration unit. In addition, we draw generalizable insights for designing such system and discuss integration plans.

Original languageEnglish
Pages (from-to)D41-D49
JournalApplied Optics
Issue number14
Publication statusPublished - 10 Apr 2024
Externally publishedYes

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Engineering (miscellaneous)
  • Electrical and Electronic Engineering


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