A new real-time control system will be implemented within the Keck II adaptive optics system to support the new near-infrared pyramid wavefront sensor. The new real-time computer has to interface with an existing, very productive adaptive optics system. We discuss our solution to install it in an operational environment without impacting science. This solution is based on an independent SCExAO-based pyramid wavefront sensor realtime processor solution using the hardware interfaces provided by the existing Keck II real-time controller. We introduce the new pyramid real-time controller system design, its expected performance, and the modification of the operational real-time controller to support the pyramid system including interfacing with the existing deformable and tip-tilt mirrors. We describe the integration of the Saphira detector-based camera and the Boston Micromachines kilo-DM in this new architecture. We explain the software architecture and philosophy, the shared memory concept and how the real-time computer uses the power of GPUs for adaptive optics control. We discuss the strengths and weaknesses of this architecture and how it can benefit other projects. The motion control of the devices deployed on the Keck II adaptive optics bench to support the alignment of the light on the sensors is also described. The interfaces, developed to deal with the rest of the Keck telescope systems in the observatory distributed system, are reviewed. Based on this experience, we present which design ideas could have helped us integrate the new system with the previous one and the resultant performance gains.
Wavefront sensing in the infrared is highly desirable for the study of M-type stars and cool red objects, as they are sufficiently bright in the infrared to be used as the adaptive optics guide star. This aids in high contrast imaging, particularly for low mass stars where the star-to-planet brightness ratio is reduced. Here we discuss the combination of infrared detector technology with the highly sensitive Pyramid wavefront sensor (WFS) for a new generation of systems. Such sensors can extend the capabilities of current telescopes and meet the requirements for future instruments, such as those proposed for the giant segmented mirror telescopes. Here we introduce the infrared Pyramid WFS and discuss the advantages and challenges of this sensor. We present a new infrared Pyramid WFS for Keck, a key sub-system of the Keck Planet Imager and Characterizer (KPIC). The design, integration and testing is reported on, with a focus on the characterization of the SAPHIRA detector used to provide the H-band wavefront sensing. Initial results demonstrate a required effective read noise <1e<sup>–</sup> at high gain.
We report on initial results from the largest infrared AO direct imaging survey searching for wide orbit (≳ 100 AU) massive exoplanets and brown dwarfs as companions around young nearby stars using Robo-AO at the 2.1-m telescope on Kitt Peak, Arizona. The occurrence rates of these rare substellar companions are critical to furthering our understanding of the origin of planetary-mass companions on wide orbits. The observing efficiency of Robo-AO allows us to conduct a survey an order of magnitude larger than previously possible. We commissioned a low-noise high-speed SAPHIRA near-infrared camera to conduct this survey and report on its sensitivity, performance, and data reduction process.
iSHELL is 1.10-5.3 μm high spectral resolution spectrograph being built for the NASA Infrared Telescope Facility on Maunakea, Hawaii. Dispersion is accomplished with a silicon immersion grating in order to keep the instrument small enough to be mounted at the Cassegrain focus of the telescope. The white pupil spectrograph produces resolving powers of up to R=75,000. Cross-dispersing gratings mounted in a tilt-able mechanism allow observers to select different wavelength ranges and, in combination with a slit wheel and Dekker mechanism, slit lengths ranging from 5ʺ″ to 25ʺ″. One Teledyne 2048x2048 Hawaii 2RG array is used in the spectrograph, and one Raytheon 512x512 Aladdin 2 array is used in a slit viewer for object acquisition and guiding. First light is expected in mid-2016. In this paper we discuss details of the construction, assembly and laboratory testing.
We present the measured characteristics of the most recent iteration of SAPHIRA HgCdTe APD arrays, and
with suppressed glow show them to be capable of a baseline dark current of 0:03e<sup>-</sup>/s. Under high bias voltages
the device also reaches avalanche gains greater than 500. The application of a high temperature anneal during
production shows great improvements to cosmetic performance and moves the SAPHIRA much closer to being
science grade arrays. We also discuss investigations into photon counting and ongoing telescope deployments of
the SAPHIRA with UH-IfA.
The PanSTARRS project has undertaken an ambitious effort to develop a completely new array controller architecture that is fundamentally driven by the large 1gigapixel, low noise, high speed OTCCD mosaic requirements as well as the size, power and weight restrictions of the PanSTARRS telescope. The result is a very small form factor next generation controller scalar building block with 1 Gigabit Ethernet interfaces that will be assembled into a system that will readout 512 outputs at ~1 Megapixel sample rates on each output. The paper will also discuss critical technology and fabrication techniques such as greater than 1MHz analog to digital converters (ADCs), multiple fast sampling and digital calculation of multiple correlated samples (DMCS), ball grid array (BGA) packaged circuits, LINUX running on embedded field programmable gate arrays (FPGAs) with hard core microprocessors for the prototype currently being developed.
The design of the Redstar3 array control system including operational requirements and performance is presented. The architecture is intended to support next generation large format infrared/optical arrays and mosaics by using a new scalable approach that takes advantage of commercially available electronics. Specifically, an approach of using a combination of high speed fiber links, networked PCs and Linux to replace the previous generation of VME based DSPs will be discussed in detail. The design will be used to control HAWAII-2RG (1-4.9μm 2Kx2K HgCdTe), Aladdin II and III (1-5 μm 1Kx1K InSb) arrays in facility class instruments for Gemini, NSO and IRTF. It is also intended to be the platform for high count curvature correction, waveform sense and control for adaptive optics.