AST3-NIR is a new infrared camera for deployment with the AST3-3 wide-field survey telescope to Dome A on the Antarctic plateau. This project is designed to take advantage of the low Antarctic infrared sky thermal background (particularly within the K<sub>dark</sub> near infrared atmospheric window at 2.4 μm) and the long Antarctic nights to provide high sensitivity temporal data from astronomical sources. The data collected from the Kunlun Infrared Sky Survey (KISS) will be used to conduct a range of astronomical science cases including the study of supernovae, exo-planets, variable stars, and the cosmic infrared background.
ULTIMATE is an instrument concept under development at the AAO, for the Subaru Telescope, which will have the unique combination of ground layer adaptive optics feeding multiple deployable integral field units. This will allow ULTIMATE to probe unexplored parameter space, enabling science cases such as the evolution of galaxies at z ~ 0:5 to 1.5, and the dark matter content of the inner part of our Galaxy. ULTIMATE will use Starbugs to position between 7 and 13 IFUs over a 14 × 8 arcmin field-of-view, pro- vided by a new wide-field corrector. All Starbugs can be positioned simultaneously, to an accuracy of better than 5 milli-arcsec within the typical slew-time of the telescope, allowing for very efficient re-configuration between observations. The IFUs will feed either the near-infrared nuMOIRCS or the visible/ near-infrared PFS spectrographs, or both. Future possible upgrades include the possibility of purpose built spectrographs and incorporating OH suppression using fibre Bragg gratings. We describe the science case and resulting design requirements, the baseline instrument concept, and the expected performance of the instrument.
Atmospheric emission from OH molecules is a long standing problem for near-infrared astronomy. PRAXIS is a unique spectrograph, currently in the build-phase, which is fed by a fibre array that removes the OH background. The OH suppression is achieved with fibre Bragg gratings, which were tested successfully on the GNOSIS instrument. PRAXIS will use the same fibre Bragg gratings as GNOSIS in the first implementation, and new, less expensive and more efficient, multicore fibre Bragg gratings in the second implementation. The OH lines are suppressed by a factor of ~1000, and the expected increase in the signal-to-noise in the interline regions compared to GNOSIS is a factor of ~ 9 with the GNOSIS gratings and a factor of ~ 17 with the new gratings. PRAXIS will enable the full exploitation of OH suppression for the first time, which was not achieved by GNOSIS due to high thermal emission, low spectrograph transmission, and detector noise. PRAXIS will have extremely low thermal emission, through the cooling of all significantly emitting parts, including the fore-optics, the fibre Bragg gratings, a long length of fibre, and a fibre slit, and an optical design that minimises leaks of thermal emission from outside the spectrograph. PRAXIS will achieve low detector noise through the use of a Hawaii-2RG detector, and a high throughput through an efficient VPH based spectrograph. The scientific aims of the instrument are to determine the absolute level of the interline continuum and to enable observations of individual objects via an IFU. PRAXIS will first be installed on the AAT, then later on an 8m class telescope.
MANIFEST is a facility multi-object fibre system for the Giant Magellan Telescope, which uses ‘Starbug’ fibre positioning robots. MANIFEST, when coupled to the telescope’s planned seeing-limited instruments, GMACS, and G-CLEF, offers access to: larger fields of view; higher multiplex gains; versatile reformatting of the focal plane via IFUs; image-slicers; and in some cases higher spatial and spectral resolution. The Prototyping Design Study phase for MANIFEST, nearing completion, has focused on developing a working prototype of a Starbugs system, called TAIPAN, for the UK Schmidt Telescope, which will conduct a stellar and galaxy survey of the Southern sky. The Prototyping Design Study has also included work on the GMT instrument interfaces. In this paper, we outline the instrument design features of TAIPAN, highlight the modifications that will be necessary for the MANIFEST implementation, and provide an update on the MANIFEST/instrument interfaces.
Hector<sup>[1,2,3]</sup> will be the new massively-multiplexed integral field spectroscopy (IFS) instrument for the Anglo-Australian Telescope (AAT) in Australia and the next main dark-time instrument for the observatory. Based on the success of the SAMI instrument, which is undertaking a 3400-galaxy survey, the integral field unit (IFU) imaging fibre bundle (hexabundle) technology under-pinning SAMI is being improved to a new innovative design for Hector. The distribution of hexabundle angular sizes is matched to the galaxy survey properties in order to image 90% of galaxies out to 2 effective radii. 50-100 of these IFU imaging bundles will be positioned by ‘starbug’ robots across a new 3-degree field corrector top end to be purpose-built for the AAT. Many thousand fibres will then be fed into new replicable spectrographs. Fundamentally new science will be achieved compared to existing instruments due to Hector's wider field of view (3 degrees), high positioning efficiency using starbugs, higher spectroscopic resolution (R=3000-5500 from 3727-7761Å, with a possible redder extension later) and large IFUs (up to 30 arcsec diameter with 61-217 fibre cores). A 100,000 galaxy IFS survey with Hector will decrypt how the accretion and merger history and large-scale environment made every galaxy different in its morphology and star formation history. The high resolution, particularly in the blue, will make Hector the only instrument to be able to measure higher-order kinematics for galaxies down to much lower velocity dispersion than in current large IFS galaxy surveys, opening up a wealth of new nearby galaxy science.
TAIPAN will conduct a stellar and galaxy survey of the Southern sky. The TAIPAN positioner is being developed as a prototype for the MANIFEST instrument on the GMT. The design for TAIPAN incorporates 150 optical fibres (with an upgrade path to 300) situated within independently controlled robotic positioners known as Starbugs. Starbugs allow precise parallel positioning of individual fibres, thus significantly reducing instrument configuration time and increasing the amount of observing time. Presented is an engineering overview of the UKST upgrade of the completely new Instrument Spider Assembly utilized to support the Starbug Fibre Positioning Robot and current status of the Starbug itself.
TAIPAN will conduct a stellar and galaxy survey of the Southern sky. The TAIPAN positioner is being developed as a prototype for the MANIFEST instrument on the GMT. The TAIPAN Spectrograph is an AAO designed all-refractive 2-arm design that delivers a spectral resolution of R>2000 over the wavelength range 370-870 nm. It is fed by a custom fibre cable from the TAIPAN Starbugs positioner. The design for TAIPAN incorporates 150 optical fibres (with an upgrade path to 300). Presented is an engineering overview of the UKST Fibre Cable design used to support Starbugs, the custom slit design, and the overall design and build plan for the TAIPAN Spectrograph.
The High Efficiency and Resolution Multi Element Spectrograph, HERMES, is a facility-class optical spectrograph for the Anglo-Australian Telescope (AAT). It is designed primarily for Galactic Archaeology, the first major attempt to create a detailed understanding of galaxy formation and evolution by studying the history of our own galaxy, the Milky Way. The goal of the GALAH survey is to reconstruct the mass assembly history of the Milky Way through a detailed chemical abundance study of one million stars. The spectrograph is based at the AAT and is fed by the existing 2dF robotic fiber positioning system. The spectrograph uses volume phase holographic gratings to achieve a spectral resolving power of 28,000 in standard mode and also provides a high-resolution mode ranging between 40,000 and 50,000 using a slit mask. The GALAH survey requires an SNR greater than 100 for a star brightness of V=14 in an exposure time of one hour. The total spectral coverage of the four channels is about 100 nm between 370 and 1000 nm for up to 392 simultaneous targets within the 2-degree field of view. HERMES has been commissioned over three runs, during bright time in October, November, and December 2013, in parallel with the beginning of the GALAH pilot survey, which started in November 2013. We present the first-light results from the commissioning run and the beginning of the GALAH survey, including performance results such as throughput and resolution, as well as instrument reliability.
Starbugs are miniature piezoelectric ‘walking’ robots that can be operated in parallel to position many payloads (e.g.
optical fibres) across a telescope’s focal plane. They consist of two concentric piezo-ceramic tubes that walk with micron
step size. In addition to individual optical fibres, Starbugs have moved a payload of 0.75kg at several millimetres per
second. The Australian Astronomical Observatory previously developed prototype devices and tested them in the
laboratory. Now we are optimising the Starbug design for production and deployment in the TAIPAN instrument, which
will be capable of configuring 300 optical fibres over a six degree field-of-view on the UK Schmidt Telescope within a
few minutes. The TAIPAN instrument will demonstrate the technology and capability for MANIFEST (Many Instrument
Fibre-System) proposed for the Giant Magellan Telescope. Design is addressing: connector density and voltage
limitations, mechanical reliability and construction repeatability, field plate residues and scratching, metrology stability,
and facilitation of improved motion in all aspects of the design for later evaluation. Here we present the new design
features of the AAO TAIPAN Starbug.
MANIFEST is a fibre feed system for the Giant Magellan Telescope that, coupled to the seeing-limited instruments
GMACS and G-CLEF, offers qualitative and quantitative gains over each instrument’s native capabilities in terms of
multiplex, field of view, and resolution. The MANIFEST instrument concept is based on a system of semi-autonomous
probes called “Starbugs” that hold and position hundreds of optical fibre IFUs under a glass field plate placed at the
GMT Cassegrain focal plane. The Starbug probes feature co-axial piezoceramic tubes that, via the application of
appropriate AC waveforms, contract or bend, providing a discrete stepping motion. Simultaneous positioning of all
Starbugs is achieved via a closed-loop metrology system.
The High Efficiency and Resolution Multi Element Spectrograph (HERMES) is a four channel, VPH-grating spectrograph fed by two 400 fiber slit assemblies whose construction and commissioning has now been completed at the Anglo Australian Telescope (AAT). The size, weight, complexity, and scheduling constraints of the system necessitated that a fully integrated, deterministic, opto-mechanical alignment system be designed into the spectrograph before it was manufactured. This paper presents the principles about which the system was assembled and aligned, including the equipment and the metrology methods employed to complete the spectrograph integration.
PRAXIS is a second generation instrument that follows on from GNOSIS, which was the first instrument using fibre
Bragg gratings for OH suppression to be deployed on a telescope. The Bragg gratings reflect the NIR OH lines while
being transparent to the light between the lines. This gives in principle a much higher signal-noise ratio at low resolution
spectroscopy but also at higher resolutions by removing the scattered wings of the OH lines. The specifications call for
high throughput and very low thermal and detector noise so that PRAXIS will remain sky noise limited even with the
low sky background levels remaining after OH suppression. The optical and mechanical designs are presented. The
optical train starts with fore-optics that image the telescope focal plane on an IFU which has 19 hexagonal microlenses
each feeding a multi-mode fibre. Seven of these fibres are attached to a fibre Bragg grating OH suppression system while
the others are reference/acquisition fibres. The light from each of the seven OH suppression fibres is then split by a
photonic lantern into many single mode fibres where the Bragg gratings are imprinted. Another lantern recombines the
light from the single mode fibres into a multi-mode fibre. A trade-off was made in the design of the IFU between field of
view and transmission to maximize the signal-noise ratio for observations of faint, compact objects under typical seeing.
GNOSIS used the pre-existing IRIS2 spectrograph while PRAXIS will use a new spectrograph specifically designed for
the fibre Bragg grating OH suppression and optimised for 1.47 μm to 1.7 μm (it can also be used in the 1.09 μm to 1.26
μm band by changing the grating and refocussing). This results in a significantly higher transmission due to high
efficiency coatings, a VPH grating at low incident angle and optimized for our small bandwidth, and low absorption
glasses. The detector noise will also be lower thanks to the use of a current generation HAWAII-2RG detector.
Throughout the PRAXIS design, from the fore-optics to the detector enclosure, special care was taken at every step along
the optical path to reduce thermal emission or stop it leaking into the system. The spectrograph design itself was
particularly challenging in this aspect because practical constraints required that the detector and the spectrograph
enclosures be physically separate with air at ambient temperature between them. At present, the instrument uses the
GNOSIS fibre Bragg grating OH suppression unit. We intend to soon use a new OH suppression unit based on multicore
fibre Bragg gratings which will allow an increased field of view per fibre. Theoretical calculations show that the gain in
interline sky background signal-noise ratio over GNOSIS may very well be as high as 9 with the GNOSIS OH
suppression unit and 17 with the multicore fibre OH suppression unit.
Hector is an instrument concept for a multi integral-field-unit spectrograph aimed at obtaining a tenfold increase in
capability over the current generation of such instruments. The key science questions for this instrument include how do
galaxies get their gas, how is star formation and nuclear activity affected by environment, what is the role of feedback,
and what processes can be linked to galaxy groups and clusters. The baseline design for Hector incorporates multiple
hexabundle fibre integral-field-units that are each positioned using Starbug robots across a three-degree field at the
Anglo-Australian Telescope. The Hector fibres feed dedicated fixed-format spectrographs, for which the parameter space
is currently being explored.
The KOALA optical fibre feed for the AAOmega spectrograph has been commissioned at the Anglo-Australian
Telescope. The instrument samples the reimaged telescope focal plane at two scales: 1.23 arcsec and 0.70 arcsec per
image slicing hexagonal lenslet over a 49x27 and 28x15 arcsec field of view respectively. The integral field unit consists
of 2D hexagonal and circular lenslet arrays coupling light into 1000 fibres with 100 micron core diameter. The fibre run
is over 35m long connecting the telescope Cassegrain focus with the bench mounted spectrograph room where all fibres
are reformatted into a one-dimensional slit. Design and assembly of the KOALA components, engineering challenges
encountered, and commissioning results are discussed.
TAIPAN is a spectroscopic instrument designed for the UK Schmidt Telescope at the Australian Astronomical Observatory. In addition to undertaking the TAIPAN survey, it will serve as a prototype for the MANIFEST fibre positioner system for the future Giant Magellan Telescope. The design for TAIPAN incorporates up to 300 optical fibres situated within independently-controlled robotic positioners known as Starbugs, allowing precise parallel positioning of every fibre, thus significantly reducing instrument configuration time and increasing observing time. We describe the design of the TAIPAN instrument system, as well as the science that will be accomplished by the TAIPAN survey. We also highlight results from the on-sky tests performed in May 2014 with Starbugs on the UK Schmidt Telescope and briefly introduce the role that Starbugs will play in MANIFEST.
The High Efficiency and Resolution Multi Element Spectrograph, HERMES is an facility-class optical spectrograph for
the AAT. It is designed primarily for Galactic Archeology , the first major attempt to create a detailed
understanding of galaxy formation and evolution by studying the history of our own galaxy, the Milky Way. The goal of
the GALAH survey is to reconstruct the mass assembly history of the of the Milky Way, through a detailed spatially
tagged abundance study of one million stars. The spectrograph is based at the Anglo Australian Telescope (AAT) and is
fed by the existing 2dF robotic fiber positioning system. The spectrograph uses VPH-gratings to achieve a spectral
resolving power of 28,000 in standard mode and also provides a high-resolution mode ranging between 40,000 to 50,000
using a slit mask. The GALAH survey requires a SNR greater than 100 for a star brightness of V=14. The total spectral
coverage of the four channels is about 100nm between 370 and 1000nm for up to 392 simultaneous targets within the 2
degree field of view. Hermes has been commissioned over 3 runs, during bright time in October, November and
December 2013, in parallel with the beginning of the GALAH Pilot survey starting in November 2013. In this paper we
present the first-light results from the commissioning run and the beginning of the GALAH Survey, including
performance results such as throughput and resolution, as well as instrument reliability. We compare the abundance
calculations from the pilot survey to those in the literature.
We present a concept for a 4000-fibre positioner for DESpec, based on the Echidna ‘tilting spine’ technology. The DESpec focal plane is 450mm across and curved, and the required pitch is ~6.75mm. The size, number of fibers and curvature are all comparable with various concept studies for similar instruments already undertaken at the AAO, but present new challenges in combination. A simple, low-cost, and highly modular design is presented, consisting of identical modules populated by identical spines. No show-stopping issues in accommodating either the curvature or the smaller pitch have been identified, and the actuators consist largely of off-the-shelf components. The actuators have been prototyped at AAO, and allow reconfiguration times of ~15s to reach position errors 7 microns or less. Straightforward designs for metrology, acquisition, and guiding are also proposed. The throughput losses of the entire positioner system are estimated to be ~15%, of which 6.3% is attributable to the tilting-spine technology.
The High Efficiency and Resolution Multi Element Spectrograph, HERMES is an optical spectrograph designed
primarily for the GALAH, Galactic Archeology Survey, the first major attempt to create a detailed understanding of
galaxy formation and evolution by studying the history of our own galaxy, the Milky Way<sup>1</sup>. The goal of the GALAH
survey is to reconstruct the mass assembly history of the of the Milky way, through a detailed spatially tagged
abundance study of one million stars in the Milky Way. The spectrograph will be based at the Anglo Australian
Telescope (AAT) and be fed with the existing 2dF robotic fibre positioning system. The spectrograph uses VPH-gratings
to achieve a spectral resolving power of 28,000 in standard mode and also provides a high resolution mode ranging
between 40,000 to 50,000 using a slit mask. The GALAH survey requires a SNR greater than 100 aiming for a star
brightness of V=14. The total spectral coverage of the four channels is about 100nm between 370 and 1000nm for up to
392 simultaneous targets within the 2 degree field of view.
Current efforts are focused on manufacturing and integration. The delivery date of spectrograph at the telescope is
scheduled for 2013. A performance prediction is presented and a complete overview of the status of the HERMES
spectrograph is given. This paper details the following specific topics:
The approach to AIT, the manufacturing and integration of the large mechanical frame, the opto-mechanical slit
assembly, collimator optics and cameras, VPH gratings, cryostats, fibre cable assembly, instrument control hardware and
software, data reduction.
KOALA, the Kilofibre Optimised Astronomical Lenslet Array, is a wide-field, high efficiency integral field unit
being designed for use with the bench mounted AAOmega spectrograph on the AAT. KOALA will have 1000
fibres in a rectangular array with a selectable field of view of either 1390 or 430 sq. arcseconds with a spatial
sampling of 1.25" or 0.7" respectively. To achieve this KOALA will use a telecentric double lenslet array with
interchangeable fore-optics. The IFU will feed AAOmega via a 31m fibre run. The efficiency of KOALA is
expected to be ≈ 52% at 3700A and ≈ 66% at 6563°Å with a throughput of > 52% over the entire wavelength
The Australian Astronomical Observatory is building a 4-channel VPH-grating High Efficiency and Resolution Multi
Element Spectrograph (HERMES) for the 3.9 meter Anglo-Australian Telescope (AAT). HERMES will provide a
nominal spectral resolving power of 28,000 for Galactic Archaeology with an optional high-resolution mode of 45,000
with the use of a slit mask.
HERMES is fed by a fibre positioning robot called 2dF at the telescope prime focus. There are a total of 784 science
fibres, which interface with the spectrograph via two separate slit body assemblies, each comprising of 392 science
fibers. The slit defines the spectral lines of 392 fibres on the detector. The width of the detector determines the spectral
bandwidth and the detector height determines the fibre to fibre spacing or cross talk. Tolerances that follow from this are
all in the 10 micrometer range.
The slit relay optics must contribute negligibly to the overall image quality budget and uniformly illuminate the
spectrograph exit pupil. The latter requirement effectively requires that the relay optics provide a telecentric input at the
collimator entrance slit. As a result it is critical to align the optical components to extreme precision required by the
This paper discusses the engineering challenges of designing, optimising, tolerancing and manufacturing of very precise
mechanical components for housing optics and the design of low cost of jigs and fixtures for alignment and assembly of
CYCLOPS2 is an upgrade for the UCLES high resolution spectrograph on the Anglo-Australian Telescope, scheduled for commissioning in semester 2012A. By replacing the 5 mirror Coud´e train with a Cassegrain mounted fibre-based image slicer CYCLOPS2 simultaneously provides improved throughput, reduced aperture losses and increased spectral resolution. Sixteen optical fibres collect light from a 5.0 arcsecond<sup>2</sup> area of sky and reformat it into the equivalent of a 0.6 arcsecond wide slit, delivering a spectral resolution of R= 70000 and up to twice as much flux as the standard 1 arcsecond slit of the Coud´e train. CYCLOPS2 also adds support for simultaneous ThAr wavelength calibration via a dedicated fibre. CYCLOPS2 consists of three main components, the fore-optics unit, fibre bundle and slit unit. The fore optics unit incorporates magnification optics and a lenslet array and is designed to mount to the CURE Cassegrain instrument interface, which provides acquisition, guiding and calibration facilities. The fibre bundle transports the light from the Cassegrain focus to the UCLES spectrograph at Coud´e and also includes a fibre mode scrambler. The slit unit consists of the fibre slit and relay optics to project an image of the slit onto the entrance aperture of the UCLES spectrograph. CYCLOPS2 builds on experience with the first generation CYCLOPS fibre system, which we also describe in this paper. We present the science case for an image slicing fibre feed for echelle spectroscopy and describe the design of CYCLOPS and CYCLOPS2.
The Gemini High-Resolution Optical SpecTrograph (GHOST) will fill an important gap in the current suite of Gemini
instruments. We will describe the Australian Astronomical Observatory (AAO)-led concept for GHOST, which consists
of a multi-object, compact, high-efficiency, fixed-format, fiber-fed design. The spectrograph itself is a four-arm variant
of the asymmetric white-pupil echelle Kiwispec spectrograph, Kiwisped, produced by Industrial Research Ltd. This
spectrograph has an R4 grating and a 100mm pupil, and separate cross-disperser and camera optics for each of the four
arms, carefully optimized for their respective wavelength ranges. We feed this spectrograph with a miniature lensletbased
IFU that sub-samples the seeing disk of a single object into 7 hexagonal sub-images, reformatting this into a slit
with a second set of double microlenses at the spectrograph entrance with relatively little loss due to focal-ratio
degradation. This reformatting enables high spectral resolution from a compact design that fits well within the relatively
tight GHOST budget. We will describe our baseline 2-object R~50,000 design with full wavelength coverage from the
ultraviolet to the silicon cutoff, as well as the high-resolution single-object R~75,000 mode.
Following the successful commissioning of SAMI (Sydney-AAO Multi-object IFU) the AAO has undertaken concept
studies leading to a design of a new instrument for the AAT (Hector). It will use an automated robotic system for the
deployment of fibre hexabundles to the focal plane. We have analysed several concepts, which could be applied in the
design of new instruments or as a retrofit to existing positioning systems. We look at derivatives of Starbugs that could
handle a large fibre bundle as well as modifications to pick and place robots like 2dF or OzPoz. One concept uses large
magnetic buttons that adhere to a steel field plate with substantial force. To move them we replace the gripper with a
pneumatic device, which engages with the button and injects it with compressed air, thus forming a magnet preloaded air
bearing allowing virtually friction-less repositioning of the button by a gantry or an R-Theta robot. New fibre protection,
guiding and retraction systems are also described. These developments could open a practical avenue for the upgrade to a
number of instruments.