The Calibration System for IGRINS, a High Resolution Near-IR Spectrograph
Abstract
IGRINS (the Immersion GRating INfrared Spectrograph) is a high resolution infrared spectrograph which is developed by a collaboration of the University of Texas at Austin, Korea Astronomy and Space Science Institute, and Kyung Hee University. IGRINS is the forerunner for GMTNIRS (the Giant Magellan Telescope Near Infrared Spectrograph) which has been selected for study as a first-light instrument for GMT. IGRINS uses a silicon immersion grating as an echelle grating and VPH gratings are used as cross dispersers. IGRINS can observe the whole H- and K- bands in a single exposure and will have a resolving power of 40,000 with 0.68" entrance slit width at a 4m telescope. IGRINS will be placed initially on the McDonald 2.7m Harlan J. Smith telescope and later on 4-8m class telescopes.
The calibration system will use Th-Ar hallow cathode lamp which is well known as a line emitting source at visible and near infrared and a tungsten halogen lamp in an integrating sphere to make a blackbody source for the flat-fielding. We also use OH emission lines and telluric absorption lines for line references and we are considering to adopt a gas absorption cell for the observation requiring more precise calibration using our high dispersion instrument. We are now optimizing the optical design for the calibration system to achieve 1% flatness of the flat-fielding source illumination over slit length and over the broad bands. We will soon design mechanical mounts for optical elements and sources, and moving parts.- Publication:
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American Astronomical Society Meeting Abstracts #216
- Pub Date:
- May 2010
- Bibcode:
- 2010AAS...21641510O