ALTAIR (ALTtitude conjugate Adaptive optics for the InfraRed) is the facility natural/laser guide star adaptive optics system of the Gemini North telescope. It can feed a corrected beam to Gemini instruments NIRI and NIFS. Deploying ALTAIR is "transparent" for the science instrument, as it reproduces the telescope focal ratio (f/16), pupil size and pupil position. ALTAIR is usable in the 1 - 2.5 micron range, with best results achieved in the H and K bands. L- and M-band performance is poor because of the low (~15%) transmittance of the ALTAIR optics in those bands and the greatly increased thermal background.
ALTAIR uses a 177 actuator deformable mirror (DM) and a separate tip-tilt mirror (TTM) to correct for image blurring and distortion caused by atmospheric turbulence. It is equipped with a Shack-Hartmann wave-front sensor (WFS) that uses the visible light to measure the turbulent incident wavefront. The correction is done at a rate of up to 1 kHz (one DM/TTM update every milli-second), and is optimized automatically. ALTAIR was built by the Herzberg Institute of Astrophysics (HIA), Canada.
ALTAIR Natural Guide Star (NGS) function has been offered since 2004A. In 2007A, the ALTAIR Laser Guide Star (LGS) commissioning was completed.
The Instrument Scientist for ALTAIR is Chad Trujillo, assisted by Andy Stephens, Richard McDermid and Julian Christou.