Leonardo partnered with the Institute for Astronomy (IfA), University of Hawaii to develop a 1K x 1K infrared avalanche photo diode suitable for low background science applications. Presented here is the design and thermal modeling for the Kovar carrier for mounting the detector as well as the challenges faced in designing and manufacturing the complex flex cable. The flex cable provides the 68 bond pads necessary to service the detector in a width of just over 17mm as well as providing filtering for the bias supplies. The final package is a compact, three side buttable package that has been successfully tested at an operating temperature of 80K.
One of the main challenges for the new generation of extremely large telescopes (ELT) such as the Giant Magellan Telescope (GMT) is apparent in their ability to phase the segments in their primary mirror. Due to the lack of viability of manufacturing enormous mirrors, these primary mirrors are composed of smaller segments, and therefore they must be phased. Prior to the full construction of GMT, there has been proposal to develop a small-scale laboratory testbed to reproduce elements of GMT’s design, major disturbances, and control systems. This would serve to reduce the risk in cost and time prior to commissioning. The team at the Australian National University’s (ANU) Research School of Astronomy and Astrophysics (RSAA) have developed a design concept for such a miniature version, coined Pocket-GMT. Pocket-GMT is designed to simulate GMT’s segmented primary mirror as well as introduce aberrations and distortions similar to what GMT will experience. This would present an opportunity to optimize the functionality of GMT’s control software and wavefront sensors, and to demonstrate phasing within the laboratory prior to full-scale telescope implementation. Pocket-GMT would also be compatible with later GMT instrument prototypes, thus ensuring its usefulness going into the future.
We report the design evolution for the GMT Integral Field Spectrograph, (GMTIFS). To support the range of operating modes – a spectroscopic channel providing integral field spectroscopy with variable spaxel scales, and a parallel imaging channel Nyquist sampling the LTAO corrected field of view - the design process has focused on risk mitigation for the demanding operational tolerances. We summarise results from prototype components, confirming concepts are meeting the necessary specifications. Ongoing review and simulation of the scientific requirements also leads to new demonstrations of the science that will be made possible with this new generation of high performance AO assisted instrumentation.
The recent availability of large format near-infrared detectors with sub-election readout noise is revolutionizing our approach to wavefront sensing for adaptive optics. However, as with all near-infrared detector technologies, challenges exist in moving from the comfort of the laboratory test-bench into the harsh reality of the observatory environment. As part of the broader adaptive optics program for the GMT, we are developing a near-infrared Lucky Imaging camera for operational deployment at the ANU 2.3 m telescope at Siding Spring Observatory. The system provides an ideal test-bed for the rapidly evolving Selex/SAPHIRA eAPD technology while providing scientific imaging at angular resolution rivalling the Hubble Space Telescope at wavelengths lambda = 1.3-2.5 mu m.
The Research School of Astronomy and Astrophysics have been developing adaptive optics systems for space situational awareness. As part of this program we have developed satellite imaging using compact adaptive optics systems for small (1-2 m) telescopes such as those operated by Electro Optic Systems (EOS) from the Mount Stromlo Observatory. We have focused on making compact, simple, and high performance AO systems using modern high stroke high speed deformable mirrors and EMCCD cameras. We are able to track satellites down to magnitude 10 with a Strehl in excess of 20% in median seeing.
GMTIFS is the first-generation adaptive optics integral-field spectrograph for the GMT, having been selected through a competitive review process in 2011. The GMTIFS concept is for a workhorse single-object integral-field spectrograph, operating at intermediate resolution (R~5,000 and 10,000) with a parallel imaging channel. The IFS offers variable spaxel scales to Nyquist sample the diffraction limited GMT PSF from λ ~ 1-2.5 μm as well as a 50 mas scale to provide high sensitivity for low surface brightness objects. The GMTIFS will operate with all AO modes of the GMT (Natural guide star - NGSAO, Laser Tomography – LTAO, and, Ground Layer - GLAO) with an emphasis on achieving high sky coverage for LTAO observations. We summarize the principle science drivers for GMTIFS and the major design concepts that allow these goals to be achieved.