National Research Council of Canada. National Science Infrastructure
Ground-Based and Airborne Instrumentation for Astronomy V, June 22-26, 2014
Adaptive optics; Astronomy; Iterative methods; Pixels; Exo-planets; flexure; Gemini Planet Imager; GPI; inversion; Least Square; Least squares approximations
The Gemini Planet Imager (GPI) is an instrument designed to directly image planets and circumstellar disks from 0.9 to 2.5 microns (the YJHK infrared bands) using high contrast adaptive optics with a lenslet-based integral field spectrograph. We develop an extraction algorithm based on a least-squares method to disentangle the spectra and systematic noise contributions simultaneously. We utilize two approaches to adjust for the effect of flexure of the GPI optics which move the position of light incident on the detector. The first method is to iterate the extraction to achieve minimum residual and the second is to cross-correlate the detector image with a model image in iterative extraction steps to determine an offset. Thus far, this process has made clear qualitative improvements to the cube extraction by reducing the Moiré pattern. There are also improvements to the automated routines for finding flexure offsets which are reliable to with ∼ 0.5 pixel accuracy compared to pixel accuracy prior. Further testing and optimization will follow before implementation into the GPI pipeline.
Ground-Based and Airborne Instrumentation for Astronomy V, 91474Z.