The Project 1640 instrument on the 200-inch Hale telescope at Palomar Observatory is a coronagraphic instrument with an integral field spectrograph at the back end, designed to find young, self-luminous planets around nearby stars. To reach the necessary contrast for this, the PALM-3000 adaptive optics system corrects for fast atmospheric speckles, while CAL, a phase-shifting interferometer in a Mach-Zehnder configuration, measures the quasistatic components of the complex electric field in the pupil plane following the coronagraphic stop. Two additional sensors measure and control low-order modes. These field measurements may then be combined with a system model and data taken separately using a white-light source internal to the AO system to correct for both phase and amplitude aberrations. Here, we discuss and demonstrate the procedure to maintain a half-plane dark hole in the image plane while the spectrograph is taking data, including initial on-sky performance.
@article{arxiv.1309.6357,
title = {Electric Field Conjugation with the Project 1640 coronagraph},
author = {Eric Cady and Christoph Baranec and Charles Beichman and Douglas Brenner and Rick Burruss and Justin Crepp and Richard Dekany and David Hale and Lynne Hillenbrand and Sasha Hinkley and E. Robert Ligon and Thomas Lockhart and Ben R. Oppenheimer and Ian Parry and Laurent Pueyo and Emily Rice and Lewis C. Roberts, and Jennifer Roberts and Michael Shao and Anand Sivaramakrishnan and Remi Soummer and Hong Tang and Tuan Truong and Gautam Vasisht and Fred Vescelus and J. Kent Wallace and Chengxing Zhai and Neil Zimmerman},
journal= {arXiv preprint arXiv:1309.6357},
year = {2015}
}
Comments
9 pages, 7 figures, in Proceedings of SPIE, 8864-19 (2013)