Precision time-series photometry in the thermal infrared with a “wall-eyed” pointing mode at the large binocular telescope

Eckhart Spalding, Phil Hinz, Andrew Skemer, John Hill, Vanessa P. Bailey, Amali Vaz

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Time-series photometry taken from ground-based facilities is improved with the use of comparison stars due to the short timescales of atmospheric-induced variability. However, the sky is bright in the thermal infrared (3–5 μm), and the correspondingly small fields of view of available detectors make it highly unusual to have a calibration star in the same field as a science target. Here, we present a new method of obtaining differential photometry by simultaneously imaging a science target and a calibrator star, separated by ≲2 amin, onto a 10 ×10 asec2 field-of-view detector. We do this by taking advantage of the Large Binocular Telescope’s (LBT) unique binocular design to point the two co-mounted telescopes apart and simultaneously obtain both targets in three sets of observations. Results indicate that the achievable scatter in LS-band (λc = 3.3 μm) is at the percent level for bright targets and possibly better with heavier sampling and characterization of the systematics.

Original languageEnglish (US)
Article number014504
JournalPublications of the Astronomical Society of the Pacific
Issue number983
StatePublished - Jan 2018


  • Binaries: visual < Stars
  • Infrared: general
  • Infrared: planetary systems
  • Instrumentation: adaptive optics
  • Instrumentation: miscellaneous
  • Methods: observational
  • Planets and satellites: fundamental parameters
  • Planets and satellites: individual (XO-2Nb, HD 189733b) < Planetary Systems
  • Telescopes

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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