We present an update to the 2024 Magellan Infrared Multi-Object Spectrograph (MIRMOS). MIRMOS is a wide-field (13' x 3') near-infrared (0.89-2.4 mu m) spectrograph with either a multiobject or integral-field mode. MIRMOS is designed to perform either faint-object distant-object spectroscopy, or high-signal-to-noise transmission spectroscopy of exoplanet atmosphere. MIRMOS is designed to deliver a spectral resolution of > 3, 400, delivering the Y, J, H, and K bands over four Hawaii H2RG detectors. The slit robot allows the observer to create 92 slits or a 26 '' x20 '' integral-field unit can be swapped in. In this proceeding, we describe changes since the last SPIE conference.
The Magellan InfraRed Multi-Object Spectrograph (MIRMOS) is a planned next generation multi-object and integral field spectrograph for the 6.5m Magellan telescopes at Las Campanas Observatory in Chile. MIRMOS will perform R similar to 3700 spectroscopy over a simultaneous wavelength range of 0.886 - 2.404 mu m (Y,J,H,K bands) in addition to imaging over the range of 0.7 - 0.886 mu m. The integral field mode of operation for MIRMOS will be achieved via an image slicer style integral field unit (IFU) located on a linear stage to facilitate movement into the beam during use or storage while operating in multi-object mode. The IFU will provide a similar to 20 '' x26 '' field of view (FoV) made up of 0.84 '' x26 '' slices. This will be the largest FoV IFS operating at these wavelengths from either the ground or space, making MIRMOS an ideal instrument for a wide range of science cases including studying the high redshift circumgalactic medium and emission line tracers from ionized and molecular gas in nearby galaxies. In order to achieve the desired image quality and FoV while matching the focal ratio to the multi-object mode, our slicer design makes use of novel freeform surfaces for the pupil mirrors, which require the use of high precision multi-axis diamond milling to manufacture. We present here the optical design and predicted performance of the MIRMOS IFU along with a conceptual design for the opto-mechanical system.
We report on the status of Henrietta, a new near-infrared low-resolution (R similar to 200) spectrograph for the 1-meter Swope telescope at Las Campanas Observatory in Chile. Henrietta is uniquely designed to perform transmission spectroscopy of tens of exoplanet atmospheres per year across a wide bandpass and routinely reach the photon noise limit on a nightly basis. Henrietta is currently at Carnegie Observatories, where it is undergoing assembly and optical alignment, as well as spectrophotometric testing to identify Henrietta's spectrophotometric noise floor. Upon finishing assembly and testing in Summer 2024, Henrietta will be shipped to Las Campanas Observatory where it will begin commissioning. In this talk, I will describe Henrietta's science mission, its overall design, the results of current testing, its goals for commissioning and future opportunities for collaboration.
This paper presents the design and technical progress of a precision X-Y stage for detector dithering and flexure compensation. The stage is being developed for use in the Magellan InfraRed Multi-Object Spectrograph, MIRMOS. MIRMOS is a very large Nasmyth mounted spectrograph containing a combination of refractive, reflective and diffractive optics mounted on a long cryogenic optical bench. The instrument utilizes five science cameras, each having a custom x-y stage to control the in-plane detector position within each camera, providing both dithering capability for improved sampling, and flexure compensation to correct for image motion that results from the gravity variant operation of the instrument. Designed to operate at 120 K, the stage will accurately control detector position in two orthogonal degrees of freedom, and have manual fine adjustment features to set detector tip, tilt and piston. The piezo-driven flexure stage provides high-resolution backlash-free motion of the detector and is very compact along the optical path, keeping camera length to a minimum. A magnetoresistive bridge provides position feedback in each degree of freedom, greatly reducing hysteresis, which is common in piezoelectric actuators. The system is designed to operate in open loop using a lookup table keyed to the Nasmyth rotator angle for flexure control. Here, the optomechanical design of the stage, electrical control system, and current performance results from early prototype efforts are presented and discussed.
The GMT-Consortium Large Earth Finder (G-CLEF) is the first instrument for the Giant Magellan Telescope (GMT). G-CLEF is a fiber feed, optical band echelle spectrograph that is capable of extremely precise radial velocity measurement. G-CLEF Flexure Control Camera (FCC) is included as a part in G-CLEF Front End Assembly (GCFEA), which monitors the field images focused on a fiber mirror to control the flexure and the focus errors within GCFEA. FCC consists of an optical bench on which five optical components are installed. The order of the optical train is: a collimator, neutral density filters, a focus analyzer, a reimager and a detector (Andor iKon-L 936 CCD camera). The collimator consists of a triplet lens and receives the beam reflected by a fiber mirror. The neutral density filters make it possible a broad range star brightness as a target or a guide. The focus analyzer is used to measure a focus offset. The reimager focuses the beam from the collimator onto the CCD detector focal plane. The detector module includes a linear translator and a field de-rotator. We performed thermoelastic stress analysis for lenses and their mounts to confirm the physical safety of the lens materials. We also conducted the global structure analysis for various gravitational orientations to verify the image stability requirement during the operation of the telescope and the instrument. In this article, we present the opto-mechanical detailed design of G-CLEF FCC and describe the consequence of the numerical finite element analyses for the design.
We present the design of Henrietta, is a wide-band (0.6 - 2.4 µm) low resolution spectrograph located at the 1-m Swope Telescope in Las Campanas Observatory. Henrietta is designed to routinely suppress instrumental variations in spectrophotometric flux in order to reach the photon noise limit. The primary way Henrietta achieves this is by employing a wide-slit at the telescope focal plane to mitigate time-dependent slit losses; employing a diffusing optical element to broaden the shape of the PSF and mitigate flux variations due to the intra-pixel quantum efficiency variations; a wide field-of-view for access to reference stars with similar brightness and spectral type; and minimizing the number of optical elements to keep throughput high across a wide spectral range. Henrietta is currently in the integration and testing phase and will begin science operations in early 2023.
We introduce LATIS, the Ly alpha Tomography IMACS Survey, a spectroscopic survey at Magellan designed to map the z = 2.2-2.8 intergalactic medium (IGM) in three dimensions by observing the Ly alpha forest in the spectra of galaxies and QSOs. Within an area of 1.7 deg(2), we will observe approximately half of greater than or similar to L* galaxies at z = 2.2-3.2 for typically 12 hr, providing a dense network of sightlines piercing the IGM with an average transverse separation of 2.5 h(-1) comoving Mpc (1 physical Mpc). At these scales, the opacity of the IGM is expected to be closely related to the dark matter density, and LATIS will therefore map the density field in the z similar to 2.5 universe at similar to Mpc resolution over the largest volume to date. Ultimately, LATIS will produce approximately 3800 spectra of z = 2.2-3.2 galaxies that probe the IGM within a volume of 4 x 10(6)h(-3) Mpc(3), large enough to contain a representative sample of structures from protoclusters to large voids. Observations are already complete over one-third of the survey area. In this paper, we describe the survey design and execution. We present the largest IGM tomographic maps at comparable resolution yet made. We show that the recovered matter overdensities are broadly consistent with cosmological expectations based on realistic mock surveys, that they correspond to galaxy overdensities, and that we can recover structures identified using other tracers. LATIS is conducted in Canada-France-Hawaii Telescope Legacy Survey fields, including COSMOS. Coupling the LATIS tomographic maps with the rich data sets collected in these fields will enable novel studies of environment-dependent galaxy evolution and the galaxy-IGM connection at cosmic noon.
The Magellan Infrared Multi-object Spectrograph (MIRMOS) is a near-infrared (NIR) multi-object spectrograph (MOS) and integral field unit (IFU) to be deployed at the Magellan 6.5-meter telescopes at Las Campafias Observatory. MIRMOS is designed to address frontier scientific questions in extragalactic, cosmological, and exoplanetary science. These scientific questions led us to spectrograph with an instantaneous wavelength range from 0.89-2.4 mu m with a spectral resolution > 3, 700. The spectrograph is fed by a front end that switches between a robotic mechanical slit mask capable of deploying nearly 90 slits over a 13' x 3' field, or by an image slicer IFU with a wide field of 26 '' x 20 ''. MIRMOS is currently under design at the Carnegie Observatories.
The Giant Magellan Telescope (GMT) Commissioning Camera (ComCam) is an all-refractive, focal reducing camera intended for the evaluation of telescope performance in both natural seeing and ground layer adaptive optics modes across a six arcminute field of view. As the first purpose-built, large imager for the GMT, it also provides unique public outreach functions and scientific research opportunities by enabling both narrowband and broadband imaging and photometric measurements at wavelengths between 360 and 950 nm. In addition to a discrete set of narrowband and broadband filters, inclusion of a deployable Fabry-Perot etalon will greatly enhance ComCam’s capabilities. With an image scale of 0.06 arcseconds per pixel, ComCam will be able to take full advantage of the GMT’s GLAO-corrected image quality under the best predicted conditions. ComCam has undergone a conceptual design review and is now under development in the preliminary design phase. Instrumental first light will be concurrent with that of the GMT.
The GMT-Consortium Large Earth Finder (G-CLEF) is one of the first instrument for the Giant Magellan Telescope (GMT). The G-CLEF is a fiber fed, optical band echelle spectrograph that is capable of extremely precise radial velocity measurement. The G-CLEF Flexure Control Camera (FCC) is included as a part in the G-CLEF Front End Assembly (GCFEA), which monitors the field images focused on a fiber mirror to control the flexure and the focus errors within the GCFEA. The five optical components constituting the FCC are aligned on a common optical bench. The order of the optical train is: a collimator, neutral density filters, a focus analyzer, a reimaging camera barrel, and a detector module. The collimator receives the beam reflected by the fiber mirror and consists of a triplet lens. The neutral density filters are located just after the collimator to make it possible a broad range star brightness as a target or a guide. The tent prism focus analyzer is positioned at a pupil produced by the collimator and is used to measure a focus offset. The reimaging camera barrel includes two pairs of doublet lenses to focus the beam onto the CCD focal plane. The detector module is composed of a linear translator and a field de-rotator. In this article, we present the optical and mechanical detailed designs of the G-CLEF FCC.
The GMT-Consortium Large Earth Finder (G-CLEF) is an instrument that is being designed to exceed the state-of-the-art radial velocity (RV) precision achievable with the current generation of stellar velocimeters. It is simultaneously being designed to enable a wide range of scientific programs, prominently by operating to blue wavelengths (< 3500Å). G-CLEF will be the first light facility instrument on the Giant Magellan Telescope (GMT) when the GMT is commissioned in 2023. G-CLEF is a fiber-fed, vacuum-enclosed spectrograph with an asymmetric white pupil echelle design. We discuss several innovative structural, optical and control system features that differentiate G-CLEF from previous precision RV instruments.
The GMT-Consortium Large Earth Finder (G-CLEF) is an echelle spectrograph with precision radial velocity (PRV) capability that will be a first light instrument for the Giant Magellan Telescope (GMT). G-CLEF has a PRV precision goal of 40 cm/sec (10 cm/s for multiple measurements) to enable detection of Earth-like exoplanets in the habitable zones of sun-like stars1. This precision is a primary driver of G-CLEF’s structural design. Extreme stability is necessary to minimize image motions at the CCD detectors. Minute changes in temperature, pressure, and acceleration environments cause structural deformations, inducing image motions which degrade PRV precision. The instrument’s structural design will ensure that the PRV goal is achieved under the environments G-CLEF will be subjected to as installed on the GMT azimuth platform, including: Millikelvin (0.001 °K) thermal soaks and gradients 10 millibar changes in ambient pressure Changes in acceleration due to instrument tip/tilt and telescope slewing Carbon fiber/cyanate composite was selected for the optical bench structure in order to meet performance goals. Low coefficient of thermal expansion (CTE) and high stiffness-to-weight are key features of the composite optical bench design. Manufacturability and serviceability of the instrument are also drivers of the design. In this paper, we discuss analyses leading to technical choices made to minimize G-CLEF’s sensitivity to changing environments. Finite element analysis (FEA) and image motion sensitivity studies were conducted to determine PRV performance under operational environments. We discuss the design of the optical bench structure to optimize stiffness-to-weight and minimize deformations due to inertial and pressure effects. We also discuss quasi-kinematic mounting of optical elements and assemblies, and optimization of these to ensure minimal image motion under thermal, pressure, and inertial loads expected during PRV observations.
MagAO is the new adaptive optics system with visible-light and infrared science cameras, located on the 6.5-m Magellan "Clay" telescope at Las Campanas Observatory, Chile. The instrument locks on natural guide stars (NGS) from 0th to 16th R-band magnitude, measures turbulence with a modulating pyramid wavefront sensor binnable from 28×28 to 7×7 subapertures, and uses a 585-actuator adaptive secondary mirror (ASM) to provide at wavefronts to the two science cameras. MagAO is a mutated clone of the similar AO systems at the Large Binocular Telescope (LBT) at Mt. Graham, Arizona. The high-level AO loop controls up to 378 modes and operates at frame rates up to 1000 Hz. The instrument has two science cameras: VisAO operating from 0.5-1μm and Clio2 operating from 1-5 μm. MagAO was installed in 2012 and successfully completed two commissioning runs in 2012-2013. In April 2014 we had our first science run that was open to the general Magellan community. Observers from Arizona, Carnegie, Australia, Harvard, MIT, Michigan, and Chile took observations in collaboration with the MagAO instrument team. Here we describe the MagAO instrument, describe our on-sky performance, and report our status as of summer 2014.
AbstractThe Magellan Adaptive Optics (MagAO) system saw first light in November 2012 at Las Campanas Observatory (LCO) on the 6.5m Clay telescope. Here we present an introduction to MagAO's visible wavelength diffraction limited imager, VisAO. VisAO delivers Strehl ratios greater than 30% from 0.62 microns (r') through 1 micron, where Strehl is even higher, and achieved resolutions as small as 20 milli-arcseconds. We took advantage of the excellent performance of MagAO/VisAO to conduct high contrast observations of an exoplanet in the optical. With VisAO, we are, for the first time, able to begin characterizing exoplanet atmospheres in the optical from the ground.
AbstractMagAO 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.
The Magellan Adaptive Optics system (MagAO) saw first light in November 2012 at Las Campanas Observatory on the 6.5m Clay telescope. Here we present an introduction to MagAO’s visible wavelength diffraction limited imager, VisAO. VisAO delivers Strehl ratios greater than 30% from 0.62 microns (r’) through 1 micron, where Strehl is even higher, and achieved resolutions as small as 20 milli-arcseconds. There are several design considerations which allow VisAO to achieve such good performance on a large telescope, and these will have important implications for ELT AO systems. We took advantage of the excellent performance of MagAO/VisAO to conduct high contrast observations of an exoplanet in the optical.
The heart of the 6.5 Magellan AO system (MagAO) is a 585 actuator adaptive secondary mirror (ASM) with <1 msec response times (0.7 ms typically). This adaptive secondary will allow low emissivity and high-contrast AO science. We fabricated a high order (561 mode) pyramid wavefront sensor (similar to that now successfully used at the Large Binocular Telescope). The relatively high actuator count (and small projected ~23 cm pitch) allows moderate Strehls to be obtained by MagAO in the “visible” (0.63-1.05 μm). To take advantage of this we have fabricated an AO CCD science camera called "VisAO". Complete “end-to-end” closed-loop lab tests of MagAO achieve a solid, broad-band, 37% Strehl (122 nm rms) at 0.76 μm (i’) with the VisAO camera in 0.8” simulated seeing (13 cm ro at V) with fast 33 mph winds and a 40 m Lo locked on R=8 mag artificial star. These relatively high visible wavelength Strehls are enabled by our powerful combination of a next generation ASM and a Pyramid WFS with 400 controlled modes and 1000 Hz sample speeds (similar to that used successfully on-sky at the LBT). Currently only the VisAO science camera is used for lab testing of MagAO, but this high level of measured performance (122 nm rms) promises even higher Strehls with our IR science cameras. On bright (R=8 mag) stars we should achieve very high Strehls (>70% at H) in the IR with the existing MagAO Clio2 (λ=1-5.3 μm) science camera/coronagraph or even higher (~98% Strehl) the Mid-IR (8-26 microns) with the existing BLINC/MIRAC4 science camera in the future. To eliminate non-common path vibrations, dispersions, and optical errors the VisAO science camera is fed by a common path advanced triplet ADC and is piggy-backed on the Pyramid WFS optical board itself. Also a high-speed shutter can be used to block periods of poor correction. The entire system passed CDR in June 2009, and we finished the closed-loop system level testing phase in December 2011. Final system acceptance (“pre-ship” review) was passed in February 2012. In May 2012 the entire AO system is was successfully shipped to Chile and fully tested/aligned. It is now in storage in the Magellan telescope clean room in anticipation of “First Light” scheduled for December 2012. An overview of the design, attributes, performance, and schedule for the Magellan AO system and its two science cameras are briefly presented here.