Status of commissioning stabilized infrared Fizeau interferometry with LBTI

Eckhart Spalding, Phil Hinz, Katie Morzinksi, Steve Ertel, Paul Grenz, Erin Maier, Jordan Stone, Amali Vaz

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Scopus citations


The Large Binocular Telescope Interferometer (LBTI) has the longest baseline in the world|22.7 m|for performing astronomical interferometry in Fizeau mode, which involves beam combination in a focal plane and preserves a wide field-of-view. LBTI can operate in this mode at wavelengths of 1.5-5 and 8-12 μm, making it a unique platform for carrying out high-resolution imaging of circumstellar disks, and possibly searches for planets, in the thermal infrared. Over the past five years, LBTI has carried out a considerable number of interferometric observations by combining the beams near a pupil plane to carry out nulling interferometry. This mode is useful for measuring small luminosity level offsets, such as those of exozodiacal dust disks. The Fizeau mode, by contrast, is more useful for generating an image of the target because it has more uv plane coverage. However, the Fizeau mode is still in an ongoing process of commissioning. Sensitive Fizeau observations require active phase control, increased automation, and the removal of non-common-path (NCP) differential aberrations. These maximize the fringe contrast, enable longer integrations, and reduce time overheads. We are in the process of writing a correction loop to remove NCP aberrations, and have carried out tests on old and synthetic data. We have also carried out on-sky Fizeau engineering tests in 2018B and 2019A. In this article, we share lessons learned and strategies developed as a result of these tests.

Original languageEnglish (US)
Title of host publicationTechniques and Instrumentation for Detection of Exoplanets IX
EditorsStuart B. Shaklan
ISBN (Electronic)9781510629271
StatePublished - 2019
Externally publishedYes
EventTechniques and Instrumentation for Detection of Exoplanets IX 2019 - San Diego, United States
Duration: Aug 12 2019Aug 15 2019

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceTechniques and Instrumentation for Detection of Exoplanets IX 2019
Country/TerritoryUnited States
CitySan Diego


  • Fizeau
  • Infrared
  • Interferometry
  • LBT

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


Dive into the research topics of 'Status of commissioning stabilized infrared Fizeau interferometry with LBTI'. Together they form a unique fingerprint.

Cite this