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As part of the High order Advanced Keck Adaptive optics (HAKA) project, a state-of-the-art ALPAO 2844 actuator deformable mirror (DM) will replace the more than 25 years old 349 actuator DM on the Keck Adaptive Optics (AO) bench. The increase in the number of DM actuators requires a new set of pupil-relay optics (PRO) to map the 2.5mm DM actuator spacing to the 200μm lenslet spacing on the Shack-Hartmann wavefront sensor (WFS). A new lenslet array with increased focal lengths will be procured in order to maintain current plate scales. HAKA will initially support science with the near-infrared camera (NIRC2), a single mode fiber fed spectrograph (KPIC + NIRSPEC) and a fast visible imager (ORKID). In addition, a new infrared wavefront sensor (`IWA) is being designed to support science with ORKID and a suite of new science instruments: a mid-infrared coronagraphic integral field spectrograph (SCALES) and a fiber-fed high-resolution spectrograph (HISPEC). We present the opto-mechanical design of the HAKA DM, Shack-Hartmann WFS upgrades and the `IWA system. A mount for the HAKA DM will allow for quick integration and alignment to the Keck AO bench. The upgrade to the WFS PRO includes a new set of optics and associated mounting that fits within the mechanical constraints of the existing WFS and meets the requirements of the HAKA DM. 

The first scientific observations with adaptive optics (AO) at W. M. Keck Observatory (WMKO) began in 1999. Through 2023, over 1200 refereed science papers have been published using data from the WMKO AO systems. The scientific competitiveness of AO at WMKO has been maintained through a continuous series of AO and instrument upgrades and additions. This tradition continues with AO being a centerpiece of WMKO’s scientific strategic plan for 2035. We will provide an overview of the current and planned AO projects from the context of this strategic plan. The current projects include implementation of new real-time controllers, the KAPA laser tomography system and the HAKA high-order deformable mirror system, the development of multiple advanced wavefront sensing and control techniques, the ORCAS space-based guide star project, and three new AO science instruments. We will also summarize steps toward the future strategic directions which are centered on ground-layer, visible and high-contrast AO. 

As part of the Keck Planet Finder (KPF) project, a Fiber Injection Unit (FIU) was implemented and will be deployed on the Keck Ⅰ telescope, with the aim of providing dispersion compensated and tip/tilt corrected light to the KPF instrument and accompanying H&K spectrometer. The goal of KPF is to characterize exoplanets via the radial velocity technique, with a single measurement precision of 30cm/s or better. To accomplish this, the FIU must provide a stable F-number and chief ray angle to the Science and Calcium H&K fibers. Our design approach was use a planar optical layout with atmospheric dispersion compensation for both the Science and Calcium H&K arms. A SWIR guider camera and piezo tip/tilt mirror are used to keep the target centered on the fibers. 

As part of the Keck All-sky Precision Adaptive optics (KAPA) project a laser Asterism Generator (AG) is being implemented on the Keck I telescope. The AG provides four Laser Guide Stars (LGS) to the Keck Adaptive Optics (AO) system by splitting a single 22W laser beam into four beams of equal intensity. We present the design and implementation of the AG for KAPA. We discuss the optical design and layout, the details of the mechanical design and fabrication, and the challenges of designing the assembly to fit into the limited available space on the Keck telescope. 

We calculate an optical distortion solution for the OSIRIS Imager on the Keck I telescope, by matching observations of globular clusters to a Hubble reference catalogue. This solution can be applied to correct astrometric distortions in OSIRIS frames, improving the astrometric accuracy of observations. We model the distortion with a 5th order Legendre polynomial. The distortion we find matches the expected OSIRIS distortion, and has a fit error of 0.6 mas, but has large residuals of 7 mas. We are currently iterating on an improved reference frame to improve the residual. Additionally, we have installed the Precision Calibration Unit (PCU) on the Keck I optical bench, which will generates an artificial grid of stars for use in future distortion calculations. 

The Keck All-Sky Precision Adaptive Optics (KAPA) system project will upgrade the Keck I AO system to enable laser tomography with a four laser guide star (LGS) asterism. This paper describes the new infrastructure which is being built for daytime calibration and testing of the KAPA tomographic algorithms. 

The W. M. Keck Observatory Adaptive Optics (AO) facilities have been operating with a Field Programmable Gate Array (FPGA) based real time controller (RTC) since 2007. The RTC inputs data from various AO wavefront and tip/tilt sensors; and corrects image blurring from atmospheric turbulence via deformable and tip/tilt mirrors. Since its commissioning, the Keck I and Keck II RTCs have been upgraded to support new hardware such as pyramid wavefront and infrared tip-tilt sensors. However, they are reaching the limits of their capabilities in terms of processing bandwidth and the ability to interface with new hardware. Together with the Keck All-sky Precision Adaptive optics (KAPA) project, a higher performance and a more reliable RTC is needed to support next generation capabilities such as laser tomography and sensor fusion. This paper provides an overview of the new RTC system, developed with our contractor/collaborators (Microgate, Swinburne University of Technology and Australian National University), and the initial on-sky performance. The upgrade includes an Interface Module to interface with the wavefront sensors and controlled hardware, and a Graphical Processing Unit (GPU) based computational engine to meet the system’s control requirements and to provide a flexible software architecture to allow future algorithms development and capabilities. The system saw first light in 2021 and is being commissioned in 2022 to support single conjugate laser guide star (LGS) AO, along with a more sensitive EMCCD camera. Initial results are provided to demonstrate single NGS & LGS performance, system reliability, and the planned upgrade for four LGS to support laser tomography. 

The Keck Planet Finder (KPF) is a fiber-fed, high-resolution, echelle spectrometer that specializes in the discovery and characterization of exoplanets using Doppler spectroscopy. In designing KPF, the guiding principles were high throughput to promote survey speed and access to faint targets, and high stability to keep uncalibrated systematic Doppler measurement errors below 30 cm s−1. KPF achieves optical illumination stability with a tip-tilt injection system, octagonal cross-section optical fibers, a double scrambler, and active fiber agitation. The optical bench and optics with integral mounts are made of Zerodur to provide thermo-mechanical stability. The spectrometer includes a slicer to reformat the optical input, green and red channels (445-600 nm and 600-870 nm), and achieves a resolving power of ∼97,000. Additional subsystems include a separate, medium-resolution UV spectrometer (383-402 nm) to record the Ca II H & K lines, an exposure meter for real-time flux monitoring, a solar feed for sunlight injection, and a calibration system with a laser frequency comb and etalon for wavelength calibration. KPF was installed and commissioned at the W. M. Keck Observatory in late 2022 and early 2023 and is now in regular use for scientific observations. This paper presents an overview of the as-built KPF instrument and its subsystems, design considerations, and initial on-sky performance.