39 research outputs found
On-instrument wavefront sensor design for the TMT infrared imaging spectrograph (IRIS) update
The first light instrument on the Thirty Meter Telescope (TMT) project will
be the InfraRed Imaging Spectrograph (IRIS). IRIS will be mounted on a bottom
port of the facility AO instrument NFIRAOS. IRIS will report guiding
information to the NFIRAOS through the On-Instrument Wavefront Sensor (OIWFS)
that is part of IRIS. This will be in a self-contained compartment of IRIS and
will provide three deployable wavefront sensor probe arms. This entire unit
will be rotated to provide field de-rotation. Currently in our preliminary
design stage our efforts have included: prototyping of the probe arm to
determine the accuracy of this critical component, handling cart design and
reviewing different types of glass for the atmospheric dispersion.Comment: Proceedings of the SPIE, 9147-35
MCAO for Gemini South
The multi-conjugate adaptive optics (MCAO) system design for the Gemini-South 8-meter telescope will provide near-diffraction-limited, highly uniform atmospheric turbulence compensation at near-infrared wavelengths over a 2 arc minute diameter field-of-view. The design includes three deformable mirrors optically conjugate to ranges of 0, 4.5, and 9.0 kilometers with 349, 468, and 208 actuators, five 10-Watt-class sodium laser guide stars (LGSs) projected from a laser launch telescope located behind the Gemini secondary mirror, five Shack-Hartmann LGS wavefront sensors of order 16 by 16, and three tip/tilt natural guide star (NGS) wavefront sensors to measure tip/tilt and tilt anisoplanatism wavefront errors. The WFS sampling rate is 800 Hz. This paper provides a brief overview of sample science applications and performance estimates for the Gemini South MCAO system, together with a summary of the performance requirements and/or design status of the principal subsystems. These include the adaptive optics module (AOM), the laser system (LS), the beam transfer optics (BTO) and laser launch telescope (LLT), the real time control (RTC) system, and the aircraft safety system (SALSA)
GPI Spectra of HR8799 C, D, and E in H-K Bands with KLIP Forward Modeling
We demonstrate KLIP forward modeling spectral extraction on Gemini Planet Imager coronagraphic data of HR8799, using PyKLIP. We report new and re-reduced spectrophotometry of HR8799 c, d, and e from H-K bands. We discuss a strategy for choosing optimal KLIP PSF subtraction parameters by injecting fake sources and recovering them over a range of parameters. The K1/K2 spectra for planets c and d are similar to previously published results from the same dataset. We also present a K band spectrum of HR8799e for the first time and show that our H-band spectra agree well with previously published spectra from the VLT/SPHERE instrument. We compare planets c, d, and e with M, L, and T-type field objects. All objects are consistent with low gravity mid-to-late L dwarfs, however, a lack of standard spectra for low gravity late L-type objects lead to poor fit for gravity. We place our results in context of atmospheric models presented in previous publications and discuss differences in the spectra of the three planets