The Keck All Sky Precision Adaptive optics (KAPA) project upgrades the Keck I adaptive optics system to enable laser tomography using a four laser guide star (LGS) asterism. KAPA is now in operation in both narrow field and wide field modes to optimize correction on-axis or over the science field of view of the camera. The use of four LGSs, in conjunction with a tomographic reconstructor and pseudo open-loop control, leads to a significant reduction in wavefront error. We describe the overall architecture, development of the tomographic algorithm, real-time implementation and preliminary on-sky results here. By comparing the on-sky image quality with that obtained using a single LGS (sLGS) we clearly demonstrate the benefits of laser tomography, a technology which is crucial to the success of the next generation of extremely large telescopes.

The Orbiting Configurable Artificial Star (ORCAS) mission in collaboration with the W. M. Keck Observatory has designed, assembled, built, and delivered, within 180 days, ORCAS Keck Instrument Demonstrator (ORKID) (ORCAS Keck Instrument Demonstrator), an early visible-wavelength performance demonstration with the Keck II Adaptive Optics (AO) system. The optical performance of ORKID meets the technical requirements derived from the scientific goals of having a Nyquist-sampled point spread function at 650 nm. This is achieved by diffraction-limited as-built performance with a root mean square internal wavefront error below 50 nm, which is key for the advancement of the ORCAS mission. ORKID has acquired, with a closed AO loop, no frame selection, while shifting and adding, the sharpest-ever on-sky image captured at Keck II. With a full width at half maximum of similar to 15 mas, this is the equivalent of a 9-m diffraction-limited telescope. By doing so, the immense potential and viability of the proposed Hybrid Observatory ORCAS mission are demonstrated. (c) 2025 Society of Photo-Optical Instrumentation Engineers (SPIE) [DOI:

We report on the design of 2ES (Second Earth Initiative Spectrograph): a new fiber-fed, high-resolution, high-precision radial velocity echelle spectrograph for the 2.2m ESO/MPG telescope in Chile, which will cover the visible wavelength range similar to 370nm to 850nm with a resolution of 120, 000. 2ES will be dedicated to a >5-year observing program with access to the majority (2/3) of the telescope time with the goal of discovering temperate terrestrial Earth-mass planets in the habitable zone around the bright solar-type stars. To achieve this goal, 2ES aims for ultra-high instrumental radial-velocity precision and an observing strategy that involves high-cadence observation of the brightest Sun-like stars in the Southern Hemisphere. Here, we present an overview of the project, its observation strategy, the optical design as well as the opto-mechanical concepts and calibration strategies to achieve the required instrument stability.

The Veloce spectrograph is a high resolution (R > 75000), compact, highly-stabilised, and hyper-calibrated echelle spectrograph to obtain Doppler velocities for Sun-like and M-dwarf at < 1 ms(-1). This spectrograph was built utilising multiple innovations to provide a "just -enough-stabilisation" platform, compensating the science observations with simultaneous collected data from an ultra-stabilised calibration source. The spectrograph consists of three spectral arms, one of which has been in operation while the additional two arms were undergoing construction. The first arm of the spectrograph, the Rosso arm, has a wavelength coverage of 580-930 nm was installed at the Anglo-Australian Telescope (AAT) and saw first light in September 2018. The Verde, 434-593 nm, and Azzurro, 378-437 nm, spectral arms passed the final design review in February of 2021 and were installed May and June of 2023 with first light occurring in early July 2023. This paper presents a review of the upgrade project along with discussions on the mechanical and optical designs in terms of procurement and manufacturability. We discuss the changes to the instrument driven from the lessons learned during the construction of the first arm of the spectrograph including detector electronics, optical mounts, and infrastructure, also the provisional acceptance of the installed instrument. We also include a discussion on the determination of the very tight slope error tolerances for the aspheric lenses in order to limit the influence of the mid-spatial frequencies on the spectra presented to the detector.

The Orbiting Configurable Artificial Star (ORCAS) mission in collaboration with the W. M. Keck Observatory (WMKO) is poised to deliver near diffraction limited observations in visible light. The ability to conduct such observations will enable significant scientific discoveries in fields related to Active Galactic Nuclei (AGN), Dark Energy, Flux Calibration, the High Redshift Universe, Exoplanets, and the Solar System. The ORCAS team has successfully completed three primary mission development goals to enable such observations. The performance demonstration with the ORCAS Keck Instrument Demonstrator (ORKID) captured arguably the highest resolution image at visible wavelengths from a large (10 meter) segmented telescope on the ground to date. High resolution AO imaging of the galaxy UGC 4729 in Natural Guide Star (NGS) mode was performed by locking onto a foreground asteroid passing nearby, which simulated an observation with a moving guide star validating post processing capabilities and demonstrating how regions unreachable by NGS and LGS could be explored. Additionally, the ORCAS team has successfully locked onto a laser source onboard the Laser Communications Relay Demonstration (LCRD) and closed the adaptive optics loop to perform near diffraction limited imaging at 1550 nm with the Keck 10 meter, the first demonstration of such capability with a large segmented telescope. All of these results validate the feasibility of the ORCAS mission. Following these accomplishments, ORCAS will be strongly positioned to propose a full-scale mission to upcoming opportunities.

A new breed of space-ground hybrid observatory, the Orbiting Configurable Artificial Star (ORCAS) mission is working with the W. M. Keck Observatory (WMKO) to demonstrate the viability of diffraction-limited visible imaging from large ground telescopes. To support that, we have built and delivered ORKID (The ORCAS Keck Instrument Demonstrator) as an early visible-wavelength performance demonstration with the Keck II Adaptive Optics (AO) system. By enabling AO and flux calibration observations, the low-cost ORCAS/ORKID mission will deliver highly detailed images to support many scientific advances. A community driven observation plan will provide Great Observatory quality capabilities open to all US observers. These observations will result in unique science for the mission, while also complementing and extending space-borne science

The success of the Keck telescopes' segmented mirror technology provided a basis for the development of other large and extremely large telescopes. We investigate ways to optimize the performance of the segmented mirror telescope further to (1) take on the challenges of high contrast imaging to characterize habitable zone exoplanets, (2) enable visible adaptive optics (AO), and (3) fully benefit from recent extreme AO developments. The current status of Keck telescope phasing using the phasing camera system (PCS) is briefly presented. A phase retrieval technique is presented that uses AO science instrument images to improve the phasing of the telescope primary mirror. The technique was tested on the Keck telescopes, and the first experimental results are presented along with the limitations of this approach. The static, semi-static, and dynamic nature of the residual segment piston errors are discussed, along with possible elevation-dependent residual segment piston errors. We propose that the technique be periodically used at Keck observatory to monitor and improve telescope phasing. We discuss the significance of the technique for AO observations with the existing and future large aperture optical telescopes. The ultimate goal is to push large aperture ground-based telescopes to their performance limits and make them competitive with space telescopes in terms of PSF stability to enable breakthrough science.

We present the status and plans for the Keck All sky Precision Adaptive optics (KAPA) program. KAPA includes four key science programs, an upgrade to the Keck I laser guide star (LGS) adaptive optics (AO) facility to improve image quality and sky coverage, AO telemetry based point spread function (PSF) estimates for all science exposures, and an educational component focused on broadening the participation of women and underrepresented groups in instrumentation. For the purpose of this conference we will focus on the AO facility upgrade which includes implementation of a new laser, wavefront sensor and real-time controller to support laser tomography, the laser tomography system itself, and modifications to an existing near-infrared tip-tilt sensor to support multiple natural guide star (NGS) and focus measurements.

The Keck Planet Finder (KPF) is a fiber-fed, high-resolution, high-stability spectrometer in development at the UC Berkeley Space Sciences Laboratory for the W.M. Keck Observatory. KPF is designed to characterize exoplanets via Doppler spectroscopy with a goal of a single measurement precision of 0.3 m s-1 or better, however its resolution and stability will enable a wide variety of astrophysical pursuits. Here we provide post-preliminary design review design updates for several subsystems, including: the main spectrometer, the fabrication of the Zerodur optical bench; the data reduction pipeline; fiber agitator; fiber cable design; fiber scrambler; VPH testing results and the exposure meter.

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.

MAROON-X is a fiber-fed, red-optical, high precision radial velocity spectrograph recently commissioned at the Gemini North telescope on Mauna Kea, Hawai'i. With a resolving power of 85,000 and a wavelength coverage of 500-920 nm, it delivers radial velocity measurements for late K and M dwarfs with sub-50 cm s(-1) precision. MAROON-X is currently the only optical EPRV spectrograph on a 8 m-class telescope in the northern hemisphere and the only EPRV instrument on a large telescope with full access by the entire US community. We report here on the results of the commissioning campaign in December 2019 and early science results.

The concept design for a laboratory based telescope emulator for the Giant Magellan Telescope (GMT) is described here. The Giant Magellan Telescope has a primary mirror comprised of 7 segments, and a secondary mirror with matching segmentation. The phasing of the GMT is a complex problem; a phasing testbed, Pocket-GMT, has been designed by a group within the Research School of Astronomy and Astrophysics at the Australian National University for the Giant Magellan Telescope Corporation. Pocket-GMT uses a novel technique to split the bending modes between a piston/tip-tilt surface and a deformable mirror. Pocket-GMT will demonstrate successful phasing of an optical miniature GMT by the planned prototype wavefront sensing systems. By reproducing the optical characteristics of the GMT on a small scale, Pocket-GMT will reduce the risk associated with the phasing system and provide a platform to test the telescopeFLsinstrumentation prior to commissioning.

A new prime focus corrector for the WEAVE project for the William Herschel Telescope is being produced. The corrector consists of six lens elements, the largest being 1.1 m in diameter. It also incorporates an Atmospheric Dispersion Corrector. Testing procedures for the WEAVE prime focus corrector lens elements are described here. Critical issues encountered in practice, including the influence of the lens size, wedge and weight on the testing procedure are discussed. Due to large lens dimensions, a dedicated test tower and lens support system has been developed to measure the optical surface form errors of the concave surfaces and the transmitted wavefront of each lens. For some of the lens elements, sub-aperture measurements have been performed using an off-axis Hindle sphere and the resultant OPD maps have been stitched together. The challenge of testing a wedged lens with a combination of a long radius convex surface and a short radius concave surface has been resolved by using another lens from the system as an auxiliary lens. The practice of testing convex surfaces via internal reflection/transmission through the lens element has been avoided entirely in this case and some discussion justifying the choices of metrology approach taken is given. The fabrication and acceptance testing of the lens elements has been completed within the expected time and budget, and all elements have been shown to meet requirements.

We present a summary of the cryogenic detector preamplifier development programme under way at the ANU. Cryogenic preamplifiers have been demonstrated for both near-infrared detectors (Teledyne H1RG and Leonardo SAPHIRA eAPD as part of development for the GMTIFS instrument) and optical CCDs (e2v CCD231-84 for use with the AAT/Veloce spectrograph). This approach to detector signal conditioning allows low-noise instrument amplifiers to be placed very close to an infra-red detector or optical CCD, isolating the readout path from external interference noise sources. Laboratory results demonstrate effective isolation of the readout path from external interference noise sources. Recent progress has focussed on the first on-sky deployment of four cryogenic preamp channels for the Veloce Rosso precision radial velocity spectrograph. We also outline future evolution of the current design, allowing higher speeds and further enhanced performance for the demanding applications required for the on instrument wavefront sensor on the Giant Magellan Integral Field Spectrograph (GMTIFS).