We present first on-sky results from the initial May-June commissioning runs of the LINC-NIRVANA Pathfinder at the LBT. The full LINC-NIRVANA instrument is one of the most complex ground-based astronomical systems ever built. It consists of multiple subsystems, including two multi-conjugate ground layer AO systems (MCAO) that drive the LBT adaptive secondaries, two mid-high layer AO systems with their own Xynetics 349 actuator DM’s, a fringe tracker, and a beam combiner. When the LINC-NIRVANA MCAO system is commissioned, it will be one of only two such systems on an 8-meter telescope and only such system in the northern hemisphere. In order to mitigate risk, we take a modular approach by decoupling and testing these subsystems individually. The first subsystem tested on-sky is one of the ground-layer AO systems, part of a test-bed known as the Pathfinder. The Pathfinder consists of a 12-star pyramid WFS that drives one of the LBT’s adaptive secondaries, a support structure known as “The Foot,” and the infrared test camera (IRTC), which is used for acquisition and alignment. We present our first results from the instrument and characterizations of the Mt. Graham atmospheric ground layer. Because plans for all ELTs call for ground layer correction, the Pathfinder provides valuable preliminary information not only for the full LINC-NIRVANA system, but also for future advanced MCAO systems.
© 2013 Optical Society of AmericaPDF Article