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We report the confirmation of HIP 67506 C, a new stellar companion to HIP 67506 A. We previously reported a candidate signal at 2$\lambda$/D (240~mas) in L$^{\prime}$ in MagAO/Clio imaging using the binary differential imaging technique. Several additional indirect signals showed that the candidate signal merited follow-up: significant astrometric acceleration in Gaia DR3, Hipparcos-Gaia proper motion anomaly, and overluminosity compared to single main sequence stars. We confirmed the companion, HIP 67506 C, at 0.1" with MagAO-X in April, 2022. We characterized HIP 67506 C MagAO-X photometry and astrometry, and estimated spectral type K7-M2; we also re-evaluated HIP 67506 A in light of the close companion. Additionally we show that a previously identified 9" companion, HIP 67506 B, is a much further distant unassociated background star. We also discuss the utility of indirect signposts in identifying small inner working angle candidate companions., Comment: 10 pages, 9 figures, 4 tables, accepted to MNRAS

We present the conceptual design of GMagAO-X, an extreme adaptive optics system for the 25 m Giant Magellan Telescope (GMT). We are developing GMagAO-X to be available at or shortly after first-light of the GMT, to enable early high contrast exoplanet science in response to the Astro2020 recommendations. A key science goal is the characterization of nearby potentially habitable terrestrial worlds. GMagAO-Xis a woofer-tweeter system, with integrated segment phasing control. The tweeter is a 21,000 actuator segmented deformable mirror, composed of seven 3000 actuator segments. A multi-stage wavefront sensing system provides for bootstrapping, phasing, and high order sensing. The entire instrument is mounted in a rotator to provide gravity invariance. After the main AO system, visible (g to y) and near-IR (Y to H) science channels contain integrated coronagraphic wavefront control systems. The fully corrected and, optionally, coronagraphically filtered beams will then be fed to a suite of focal plane instrumentation including imagers and spectrographs. This will include existing facility instruments at GMT via fiber feeds. To assess the design we have developed an end-to-end frequency-domain modeling framework for assessing the performance of GMagAO-X. The dynamics of the many closed-loop feedback control systems are then modeled. Finally, we employ a frequency-domain model of post-processing algorithms to analyze the final post-processed sensitivity. The CoDR for GMagAO-X was held in September, 2021. Here we present an overview of the science cases, instrument design, expected performance, and concept of operations for GMagAO-X., Comment: Submitted to Proceedings of SPIE

GMagAO-X is the near first light ExAO coronagraphic instrument for the 25.4m GMT. It is designed for a slot on the folded port of the GMT. To meet the strict ExAO fitting and servo error requirement (2KHz correction speeds. To minimize wavefront/segment piston error GMagAO-X has an interferometric beam combiner on a vibration isolated table, as part of this "21,000 actuator parallel DM". Piston errors are sensed by a Holographic Dispersed Fringe Sensor (HDFS). In addition to a coronagraph, it has a post-coronagraphic Lyot Low Order WFS (LLOWFS) to sense non-common path (NCP) errors. The LLOWFS drives a non-common path DM (NCP DM) to correct those NCP errors. GMagAO-X obtains high-contrast science and wavefront sensing in the visible and/or the NIR. Here we present our successful externally reviewed (Sept. 2021) CoDR optical-mechanical design that satisfies GMagAO-X's top-level science requirements and is compliant with the GMT instrument requirements and only requires COTS parts., 15 pages, 20 figures, Proc SPIE 12185 "Adaptive Optics Systems", "Telescopes and Instrumentation", July 2022, Montreal, Canada

The design of a CubeSat telescope for academic research purposes must balance complicated optical and structural designs with cost to maximize performance in extreme environments. Increasing the CubeSat size (eg. 6U to 12U) will increase the potential optical performance, but the cost will increase in kind. Recent developments in diamond-turning have increased the accessibility of aspheric aluminum mirrors, enabling a cost-effective regime of well-corrected nanosatellite telescopes. We present an all-aluminum versatile CubeSat telescope (VCT) platform that optimizes performance, cost, and schedule at a relatively large 95 mm aperture and 0.4 degree diffraction limited full field of view stablized by MEMS fine-steering modules. This study features a new design tool that permits easy characterization of performance degradation as a function of spacecraft thermal and structural disturbances. We will present details including the trade between on- and off-axis implementations of the VCT, thermal stability requirements and finite-element analysis, and launch survival considerations. The VCT is suitable for a range of CubeSat borne applications, which provides an affordable platform for astronomy, Earth-imaging, and optical communications., Comment: 11 pages, 9 figures, published in Optical Engineering + Applications conference in SPIE Optics + Photonics San Diego 2021

The Giant Magellan Telescope design consists of seven circular 8.4 m diameter mirrors, together forming a single 24.5 m diameter primary mirror. This large aperture and collecting area can help extreme adaptive optics systems such as GMagAOX achieve the small angular resolutions and contrasts required to image habitable zone earth-like planets around late type stars and possibly lead to the discovery of life outside of our solar system. However, the GMT mirror segments are separated by large g 30 cm gaps, creating the possibility of fluctuations in optical path differences (piston) due to flexure, wind loading, temperature effects, and atmospheric seeing. In order to utilize the full diffraction-limited aperture of the GMT for high-contrast imaging, the seven mirror segments must be co-phased to well within a fraction of a wavelength. The current design of the GMT involves seven adaptive secondary mirrors, a dispersed fringe sensor (part of the AGWS), and a pyramid wavefront sensor (NGWS) to measure and correct the total path length between segment pairs, but these methods have yet to be tested “end-to-end” in a lab environment. We present the design and prototype of a “GMT High-Contrast Phasing Testbed” which leverages the existing MagAO-X ExAO instrument to demonstrate fine phase sensing and simultaneous AO-control for high-contrast GMT natural guide star science. The testbed will simulate the GMT primary and secondary mirror phasing system. It will also simulate the future GMT ExAO instrument’s (GMagAO-X) “parallel DM” tweeter concept of splitting up the GMT pupil onto several commercial DMs using a reflective hexagonal pyramid. A dispersed fringe sensor will also be implemented into the testbed for coarse piston phase-sensing along with MagAO-X’s pyramid wavefront sensor to measure and correct the fine phasing level of the GMT primary mirror segments under realistic wind load and seeing conditions.

Here we review the current optical mechanical design of MagAO-X. The project is post-PDR and has finished the design phase. The design presented here is the baseline to which all the optics and mechanics have been fabricated. The optical/mechanical performance of this novel extreme AO design will be presented here for the first time. Some highlights of the design are: 1) a floating, but height stabilized, optical table; 2) a Woofer tweeter (2040 actuator BMC MEMS DM) design where the Woofer can be the current f/16 MagAO ASM or, more likely, fed by the facility f/11 static secondary to an ALPAO DM97 woofer; 3) 22 very compact optical mounts that have a novel locking clamp for additional thermal and vibrational stability; 4) A series of four pairs of super-polished off-axis parabolic (OAP) mirrors with a relatively wide FOV by matched OAP clocking; 5) an advanced very broadband (0.5-1.7micron) ADC design; 6) A Pyramid (PWFS), and post-coronagraphic LOWFS NCP wavefront sensor; 7) a vAPP coronagraph for starlight suppression. Currently all the OAPs have just been delivered, and all the rest of the optics are in the lab. Most of the major mechanical parts are in the lab or instrument, and alignment of the optics has occurred for some of the optics (like the PWFS) and most of the mounts. First light should be in 2019A., Comment: 10 pages, proc. SPIE 10703, Adaptive Optics IV, Austin TX, June 2018

MagAO-X is an entirely new extreme adaptive optics system for the Magellan Clay 6.5 m telescope, funded by the NSF MRI program starting in Sep 2016. The key science goal of MagAO-X is high-contrast imaging of accreting protoplanets at Hα. With 2040 actuators operating at up to 3630 Hz, MagAO-X will deliver high Strehls (> 70%), high resolution (19 mas), and high contrast (< 1 × 10^(-4)) at Hα (656 nm). We present an overview of the MagAO-X system, review the system design, and discuss the current project status.

The Richard F. Caris Mirror Lab at the University of Arizona continues the production of 8.4 m lightweight honeycomb segments for the primary mirror of the Giant Magellan Telescope. GMT will have a center segment surrounded by six identical off-axis segments, plus an additional off-axis segment to allow continuous operation as segments are removed for coating. Production highlights of the last two years include the spin-casting of Segment 5, preliminary polishing of Segment 2, and completion of the rear surface processing for Segments 3 and 4. We completed a preliminary design of the significant modifications of the test systems required for Segment 4, the center segment. We finished an upgrade of the 8.4 m polishing machine; both the upgrade and experience gained with Segment 1 have contributed to much faster polishing convergence for Segment 2. Prior to polishing Segment 2, we verified the stability and accuracy of the measurement systems by re-measuring Segment 1, achieving good agreement among multiple independent tests as well as good agreement with the original acceptance tests of Segment 1.

The Arizona Robotic Telescope Network (ARTN) project is a long term effort to develop a system of telescopes to carry out a flexible program of PI observing, survey projects, and time domain astrophysics including monitoring, rapid response, and transient/target-of-opportunity followup. Steward Observatory operates and shares in several 1-3m class telescopes with quality sites and instrumentation, largely operated in classical modes. Science programs suited to these telescopes are limited by scheduling flexibility and people-power of available observers. Our goal is to adapt these facilities for multiple co-existing queued programs, interrupt capability, remote/robotic operation, and delivery of reduced data. In the long term, planning for the LSST era, we envision an automated system coordinating across multiple telescopes and sites, where alerts can trigger followup, classification, and triggering of further observations if required, such as followup imaging that can trigger spectroscopy. We are updating telescope control systems and software to implement this system in stages, beginning with the Kuiper 61'' and Vatican Observatory 1.8-m telescopes. The Kuiper 61'' and its Mont4K camera can now be controlled and queue-scheduled by the RTS2 observatory control software, and operated from a remote room at Steward. We discuss science and technical requirements for ARTN, and some of the challenges in adapting heterogenous legacy facilities, scheduling, data pipelines, and maintaining capabilities for a diverse user base., Comment: Proceedings of SPIE Astronomical Telescopes & Instrumentation 2018, Observatory Operations: Strategies, Processes, and Systems VII

Having completed its commissioning phase, the Advanced Rayleigh guided Ground-layer adaptive Optics System (ARGOS) facility is coming online for scientific observations at the Large Binocular Telescope (LBT). With six Rayleigh laser guide stars in two constellations and the corresponding wavefront sensing, ARGOS corrects the ground-layer distortions for both LBT 8.4m eyes with their adaptive secondary mirrors. Under regular observing conditions, this set-up delivers a point spread function (PSF) size reduction by a factor of ~2--3 compared to a seeing-limited operation. With the two LUCI infrared imaging and multi-object spectroscopy instruments receiving the corrected images, observations in the near-infrared can be performed at high spatial and spectral resolution. We discuss the final ARGOS technical set-up and the adaptive optics performance. We show that imaging cases with ground-layer adaptive optics (GLAO) are enhancing several scientific programmes, from cluster colour magnitude diagrams and Milky Way embedded star formation, to nuclei of nearby galaxies or extragalactic lensing fields. In the unique combination of ARGOS with the multi-object near-infrared spectroscopy available in LUCI over a 4x4 arcmin field of view, the first scientific observations have been performed on local and high-z objects. Those high spatial and spectral resolution observations demonstrate the capabilities now at hand with ARGOS at the LBT., 21 pages, 28 figures

We present the novel design, laboratory verification, and on-sky performance of our advanced triplet atmospheric dispersion corrector (ADC), an important component of the Magellan Adaptive Optics system (MagAO), which recently achieved first light in December 2012. High-precision broadband (0.5-1.0 microns) atmospheric dispersion correction at visible wavelengths is essential both for wavefront sensing (WFS) on fainter guide stars, and for performing visible AO science using our VisAO science camera. At 2 airmasses (60 degrees from zenith) and over the waveband 500-1000 nm, our triplet design produces a 57% improvement in geometric rms spot size, a 33% improvement in encircled energy at 20 arcsec radius, and a 62% improvement in Strehl ratio when compared to a conventional doublet design. This triplet design has been fabricated, tested in the lab, and integrated into the MagAO WFS and the VisAO science camera. We present on-sky results of the ADC in operation with the MagAO system. We also present a zero-beam-deviation triplet ADC design, which will be important to future AO systems that require precise alignment of the optical axis over a large range of airmasses in addition to diffraction-limited broadband dispersion correction., Comment: PASP, August 2013

MagAO is the newly-commissioned adaptive optics (AO) instrument on the Magellan Clay telescope at Las Companas Observatory, Chile. MagAO has two co-mounted science cameras: VisAO for visible-light direct and spectral-differential imaging; and Clio for near to thermal IR direct imaging, non-redundant-mask interference, and prism spectroscopy. We demonstrate MagAO's simultaneous visible and infrared AO performance via direct images of exoplanet Beta Pictoris b. The planet was detected in 5 passbands from 0.9–5μm. Here we show the infrared images; the visible observations are presented in Males et al. 2013. MagAO is the first AO system to offer good performance with extensive coverage across the O/IR spectrum and thus offers an unprecedented opportunity to study the spectral energy distributions of directly-imaged extrasolar planetary atmospheres.

We present laboratory results of the closed-loop performance of the Magellan Adaptive Optics (AO) Adaptive Secondary Mirror (ASM), pyramid wavefront sensor (PWFS), and VisAO visible adaptive optics camera. The Magellan AO system is a 585-actuator low-emissivity high-throughput system scheduled for first light on the 6.5 meter Magellan Clay telescope in November 2012. Using a dichroic beamsplitter near the telescope focal plane, the AO system will be able to simultaneously perform visible (500-1000 nm) AO science with our VisAO camera and either 10 micron or 3-5 micron science using either the BLINC/MIRAC4 or CLIO cameras, respectively. The ASM, PWS, and VisAO camera have undergone final system tests in the solar test tower at the Arcetri Institute in Florence, Italy, reaching Strehls of 37% in i'-band with 400 modes and simulated turbulence of 14 cm ro at v-band. We present images and test results of the assembled VisAO system, which includes our prototype advanced Atmospheric Dispersion Corrector (ADC), prototype calcite Wollaston prisms for SDI imaging, and a suite of beamsplitters, filters, and other optics. Our advanced ADC performs in the lab as designed and is a 58% improvement over conventional ADC designs. We also present images and results of our unique Calibration Return Optic (CRO) test system and the ASM, which has successfully run in closed- loop at 1kHz. The CRO test is a retro reflecting optical test that allows us to test the ASM off-sky in close-loop using an artificial star formed by a fiber source.

The Magellan AO system combines a pyramid wavefront sensor and high-order adaptive secondary mirror, and will see first light on the Magellan Clay telescope in November 2012. With a 24 cm projected actuator pitch, this powerful system will enable good correction in the optical (0.5 to 1 μm). Realistic laboratory testing has produced Strehl ratios greater than 40% in i’ (0.765 μm) on bright simulated stars. On fainter stars our visible AO camera, VisAO, will work in the partially corrected regime with only short moments of good correction. We have developed a form of lucky imaging, called real time frame selection, which uses a fast shutter to block moments of bad correction, and quickly opens the shutter when the correction is good, enabling long integrations on a conventional CCD while maximizing Strehl ratio and resolution. The decision to open or shut is currently based on reconstructed WFS telemetry. Here we report on our implementation and testing of this technique in the Arcetri test tower in Florence, Italy, where we showed that long exposure i’ Strehl could be improved from 16% to 26% when the selection threshold was set to the best 10% of instantaneous Strehl. © (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

ARGOS the Advanced Rayleigh guided Ground layer adaptive Optics System for the LBT (Large Binocular Telescope) is built by a German-Italian-American consortium. It will be a seeing reducer correcting the turbulence in the lower atmosphere over a field of 2' radius. In such way we expect to improve the spatial resolution over the seeing of about a factor of two and more and to increase the throughput for spectroscopy accordingly. In its initial implementation, ARGOS will feed the two near-infrared spectrograph and imager - LUCI I and LUCI II. The system consist of six Rayleigh lasers - three per eye of the LBT. The lasers are launched from the back of the adaptive secondary mirror of the LBT. ARGOS has one wavefront sensor unit per primary mirror of the LBT, each of the units with three Shack-Hartmann sensors, which are imaged on one detector. In 2010 and 2011, we already mounted parts of the instrument at the telescope to provide an environment for the main sub-systems. The commissioning of the instrument will start in 2012 in a staged approach. We will give an overview of ARGOS and its goals and report about the status and new challenges we encountered during the building phase. Finally we will give an outlook of the upcoming work, how we will operate it and further possibilities the system enables by design.

ARGOS, the laser-guided adaptive optics system for the Large Binocular Telescope (LBT), is now under construction at the telescope. By correcting atmospheric turbulence close to the telescope, the system is designed to deliver high resolution near infrared images over a field of 4 arc minute diameter. Each side of the LBT is being equipped with three Rayleigh laser guide stars derived from six 18 W pulsed green lasers and projected into two triangular constellations matching the size of the corrected field. The returning light is to be detected by wavefront sensors that are range gated within the seeing-limited depth of focus of the telescope. Wavefront correction will be introduced by the telescope's deformable secondary mirrors driven on the basis of the average wavefront errors computed from the respective guide star constellation. Measured atmospheric turbulence profiles from the site lead us to expect that by compensating the ground-layer turbulence, ARGOS will deliver median image quality of about 0.2 arc sec across the JHK bands. This will be exploited by a pair of multi-object near-IR spectrographs, LUCIFER1 and LUCIFER2, with 4 arc minute field already operating on the telescope. In future, ARGOS will also feed two interferometric imaging instruments, the LBT Interferometer operating in the thermal infrared, and LINC-NIRVANA, operating at visible and near infrared wavelengths. Together, these instruments will offer very broad spectral coverage at the diffraction limit of the LBT's combined aperture, 23 m in size.

The Large Binocular Telescope (LBT) is now operating with the first of two permanently installed adaptive secondary mirrors, and the first of two complementary near-IR instruments called LUCIFER is operational as well. The ARGOS laser-guided ground-layer adaptive optics (GLAO) system, described elsewhere at this conference1, will build on this foundation to deliver the highest resolution over the 4 arc min wide-field imaging and multi-object spectroscopic modes of LUCIFER. In this paper, we describe a planned upgrade to ARGOS which will supplement the Rayleigh-based GLAO system with sodium laser guide stars (LGS) to fulfill the telescope's diffraction-limited potential. In its narrow-field mode of 30 arc sec, LUCIFER will deliver imaging at the Nyquist limit of the individual 8.4 m apertures down to J band and long-slit spectroscopy with resolution up to 40,000. In addition, the LBT Interferometer2 (LBTI) will cophase the two apertures, offering imaging at the diffraction limit of the 22.8 m baseline at wavelengths from 1.2 to 20 μm. In the first phase of the upgrade, a 10 W sodium LGS will be added to each half of the LBT, using the same launch telescopes mounted behind the two secondary mirrors as the Rayleigh LGS. The upgrade will rely on other components of the ARGOS infrastructure such as acquisition and guiding, and fast tip-tilt cameras. New wavefront sensors will be added to LUCIFER and LBTI. In the upgrade's second phase, the sodium and Rayleigh LGS will be used together in a hybrid tomographic sensing system. This configuration will offer the advantage that a single tip-tilt star will continue to be sufficient even for MCAO operation3, which is planned with LBT's LINC-NIRVANA instrument4,5.

ARGOS is the Laser Guide Star adaptive optics system for the Large Binocular Telescope. Aiming for a wide field adaptive optics correction, ARGOS will equip both sides of LBT with a multi laser beacon system and corresponding wavefront sensors, driving LBT's adaptive secondary mirrors. Utilizing high power pulsed green lasers the artificial beacons are generated via Rayleigh scattering in earth's atmosphere. ARGOS will project a set of three guide stars above each of LBT's mirrors in a wide constellation. The returning scattered light, sensitive particular to the turbulence close to ground, is detected in a gated wavefront sensor system. Measuring and correcting the ground layers of the optical distortions enables ARGOS to achieve a correction over a very wide field of view. Taking advantage of this wide field correction, the science that can be done with the multi object spectrographs LUCIFER will be boosted by higher spatial resolution and strongly enhanced flux for spectroscopy. Apart from the wide field correction ARGOS delivers in its ground layer mode, we foresee a diffraction limited operation with a hybrid Sodium laser Rayleigh beacon combination.

We present the optomechanical design of the Magellan VisAO Integral Field Spectrograph (VisAO IFS), designed to take advantage of Magellan's AO system and its 85.1cm concave ellipsoidal Adaptive Secondary Mirror (ASM). With 585 actuators and an equal number of actively-controlled modes, this revolutionary second generation ASM will be the first to achieve moderate Strehl ratios into the visible wavelength regime. We have designed the VisAO IFS to be coupled to either Magellan's LDSS-3 spectrogra ph or to the planned facility M2FS fiber spectrograph and to optimize VisAO science. Designed for narrow field-of-view, high spatial resolution science, this lenslet-coupled fiber-fed IFS will offer exciting opportunities for scientific advancement in a variety of fields, including protoplanetary disk morphology and chemistry, resolution and spectral classification of tight astrometric binaries, seasonal changes in the upper atmosphere of Titan, and a better understanding of the black hole M-sigma relation. Keywords: Adaptive optics, VisAO, Magellan, IFS, IFU

The Magellan AO system will begin commissioning in early 2012. Its VisAO camera will provide 20 mas FWHM images with mean Strehl ratios of ∼ 0.2 in R band on a 6.5m telescope. Depending on seeing conditions, Strehl ratio may reach temporary peaks as high as 0.5 at these wavelengths. To take advantage of these brief periods of high performance, we plan to adopt lucky imaging style data taking and reduction techniques. As part of this effort we have developed a novel real-time frame selection technique, which will use AO system telemetry and a fast shutter to limit CCD exposure to these very brief moments of higher Strehl. Here we describe the expected benefits of our frame selection techniques in various operating modes. We also present the results of laboratory characterization of the shutter, and describe the performance of predictive algorithms used to control it.

The Magellan Clay telescope is a 6.5m Gregorian telescope located in Chile at Las Campanas Observatory. The Gregorian design allows for an adaptive secondary mirror that can be tested off-sky in a straightforward manner. We have fabricated a 85 cm diameter aspheric adaptive secondary with our subcontractors and partners, the ASM passed acceptance tests in July 2010. This secondary has 585 actuators with

The Magellan Adaptive Secondary AO system, scheduled for first light in the fall of 2011, will be able to simultaneously perform diffraction limited AO science in both the mid-IR, using the BLINC/MIRAC4 10\{mu}m camera, and in the visible using our novel VisAO camera. The VisAO camera will be able to operate as either an imager, using a CCD47 with 8.5 mas pixels, or as an IFS, using a custom fiber array at the focal plane with 20 mas elements in its highest resolution mode. In imaging mode, the VisAO camera will have a full suite of filters, coronagraphic focal plane occulting spots, and SDI prism/filters. The imaging mode should provide ~20% mean Strehl diffraction-limited images over the band 0.5-1.0 \{mu}m. In IFS mode, the VisAO instrument will provide R~1,800 spectra over the band 0.6-1.05 \{mu}m. Our unprecedented 20 mas spatially resolved visible spectra would be the highest spatial resolution achieved to date, either from the ground or in space. We also present lab results from our recently fabricated advanced triplet Atmospheric Dispersion Corrector (ADC) and the design of our novel wide-field acquisition and active optics lens. The advanced ADC is designed to perform 58% better than conventional doublet ADCs and is one of the enabling technologies that will allow us to achieve broadband (0.5-1.0\{mu}m) diffraction limited imaging and wavefront sensing in the visible., Comment: Proceedings of the SPIE, 2010, Vol. 7736, 77362V

Since its beginnings, diffraction-limited ground-based adaptive optics (AO) imaging has been limited to wavelengths in the near IR ({\lambda} > 1 micron) and longer. Visible AO ({\lambda} < 1 micron) has proven to be difficult because shorter wavelengths require wavefront correction on very short spatial and temporal scales. The pupil must be sampled very finely, which requires dense actuator spacing and fine wavefront sampling with large dynamic range. In addition, atmospheric dispersion is much more significant in the visible than in the near-IR. Imaging over a broad visible band requires a very good Atmospheric Dispersion Corrector (ADC). Even with these technologies, our AO simulations using the CAOS code, combined with the optical and site parameters for the 6.5m Magellan telescope, demonstrate a large temporal variability of visible ({\lambda}=0.7 micron) Strehl on timescales of 50 ms. Over several hundred milliseconds, the visible Strehl can be as high at 50% and as low as 10%. Taking advantage of periods of high Strehl requires either the ability to read out the CCD very fast, thereby introducing significant amounts of read-noise, or the use of a fast asynchronous shutter that can block the low-Strehl light. Our Magellan VisAO camera will use an advanced ADC, a high-speed shutter, and our 585 actuator adaptive secondary to achieve broadband (0.5-1.0 micron) diffraction limited images on the 6.5m Magellan Clay telescope in Chile at Las Campanas Observatory. These will be the sharpest and deepest visible direct images taken to date with a resolution of 17 mas, a factor of 2.7 better than the diffraction limit of the Hubble Space Telescope., Comment: Proceedings of the SPIE, 2009

In addition to the BLINC/MIRAC IR science instruments, the Magellan adaptive secondary AO system will have an EEV CCD47 that can be used both for visible AO science and as a wide-field acquisition camera. The effects of atmospheric dispersion on the elongation of the diffraction limited Magellan adaptive optics system point spread function (PSF) are significant in the near IR. This elongation becomes particularly egregious at visible wavelengths, culminating in a PSF that is 2000mm long in one direction and diffraction limited (30-60 mm) in the other over the wavelength band 0.5-1.0mm for a source at 45° zenith angle. The planned Magellan AO system consists of a deformable secondary mirror with 585 actuators. This number of actuators should be sufficient to nyquist sample the atmospheric turbulence and correct images to the diffraction limit at wavelengths as short as 0.7mm, with useful science being possible as low as 0.5mm. In order to achieve diffraction limited performance over this broad band, 2000mm of lateral color must be corrected to better than 10mm. The traditional atmospheric dispersion corrector (ADC) consists of two identical counter-rotating cemented doublet prisms that correct the primary chromatic aberration. We propose two new ADC designs: the first consisting of two identical counter-rotating prism triplets, and the second consisting of two pairs of cemented counter-rotating prism doublets that use both normal dispersion and anomalous dispersion glass in order to correct both primary and secondary chromatic aberration. The two designs perform 58% and 68%, respectively, better than the traditional two-doublet design. We also present our design for a custom removable wide-field lens that will allow our CCD47 to switch back and forth between an 8.6" FOV for AO science and a 25.8" FOV for acquisition.

We report on the current status of production of the thin shells for the LBT adaptive secondary mirrors. These shells are made of Zerodur and have a front (optical) surface highly aspherical whereas the other (rear) surface is spherical. They have a 910mm diameter and an average thickness of 1.6mm. The manufacturing of these shells starts with a thick blank of Zerodur and follows the steps of: 1) optical surface figuring, 2) blank thinning, 3) rear surface grinding and polishing, 4) edges machining and 5) rear surface aluminizing. Of the three (two plus a spare) shells planned for LBT the first shell was completed and shipped to Italy for integration with magnets and the second is in advanced state of production. The third shell (spare) is planned to start production soon. In the paper we report details of production of these shells as well as the 'as built' characteristics. Details concerning the operations that follow the production, i.e. surface aluminum coating as well as handling and shipping fixtures are also reported.