Altair
Gemini NorthAO systemALTAIR (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 GNIRS.
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.
Capability Summary
Natural Guide Star (NGS)
- Guide star magnitude limit
- 11-12 mag for full correction
- 15-16 mag for partial correction
- Core FWHM~0.08"
Laser guide Star (LGS)
- High Strehl correction limits
- Guide star magnitude: 8.5 < R < 15
- Guide star within 15"
- 50% of NGS Strehl
- Low Strehl correction
- Guide star magnitude: 15 < R < 17.5-18.5 (depends on SB)
- Guide star within 25"
- Strehl of ~10%
Super Seeing (LGS+P1)
- Improves IQ by a factor of 2-3 over the natural seeing (on-axis)
- P1WFS magnitude limit: R ~ 14
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.
