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Title: First lunar occultation results from the 2.4 m Thai national telescope equipped with ULTRASPEC

The recently inaugurated 2.4 m Thai National Telescope (TNT) is equipped with, among other instruments, the ULTRASPEC low-noise, frame-transfer EMCCD camera. At the end of its first official observing season, we report on the use of this facility to record high time resolution imaging using small detector subarrays with a sampling as fast as several 10{sup 2} Hz. In particular, we have recorded lunar occultations of several stars that represent the first contribution to this area of research made from Southeast Asia with a telescope of this class. Among the results, we discuss an accurate measurement of α Cnc, which has been reported previously as a suspected close binary. Attempts by several authors to resolve this star have so far met with a lack of unambiguous confirmation. With our observation we are able to place stringent limits on the projected angular separation (<0.''003) and brightness (Δm > 5) of a putative companion. We also present a measurement of the binary HR 7072, which extends considerably the time coverage available for its yet undetermined orbit. We discuss our precise determination of the flux ratio and projected separation in the context of other available data. We conclude by providing an estimate ofmore » the performance of ULTRASPEC at TNT for lunar occultation work. This facility can help to extend the lunar occultation technique in a geographical area where no comparable resources were available until now.« less
Authors:
; ;  [1] ;  [2] ;  [3]
  1. National Astronomical Research Institute of Thailand, 191 Siriphanich Building, Huay Kaew Road, Suthep, Muang, Chiang Mai 50200 (Thailand)
  2. Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH (United Kingdom)
  3. Department of Physics, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL (United Kingdom)
Publication Date:
OSTI Identifier:
22345249
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astronomical Journal (New York, N.Y. Online); Journal Volume: 148; Journal Issue: 5; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BINARY STARS; BRIGHTNESS; COMPARATIVE EVALUATIONS; ECLIPSE; NOISE; ORBITS; RESOURCES; SAMPLING; STARS; TELESCOPES; TIME RESOLUTION; TNT