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The Fiber Multi-Object Spectrograph (FMOS) Project:
the Anglo-Australian Observatory rolePeter Gillingham*a, Anna Moore**a, Masayuki Akiyamab, Jurek Brzeskia, David Corrella, John
Dawsona, Tony Farrella, Gabriella Frosta, Jason Griesbacha, Roger Haynesa, Damien Jonesc,
Stan Miziarskia, Rolf Mullera, Scott Smedleya, Greg Smitha, Lew Wallera,
Katie Noakesd, Chris ArridgedaAnglo-Australian Observatory, PO Box 196, Epping, NSW 2117, AustraliabSubaru Telescope, Hilo, Hawaii, USAc
Prime Optics, 17 Crescent Rd., Eumundi, Qld 4562, Australiadtemporarily at Anglo-Australian Observatory

ABSTRACTThe Fiber Multi-Object Spectrograph (FMOS) project is an Australia-Japan-UK collaboration to design and build anovel 400 fiber positioner feeding two near infrared spectrographs from the prime focus of the Subaru telescope. The
project comprises several parts. Those under design and construction at the Anglo-Australian Observatory (AAO) are
the piezoelectric actuator driven fiber positioner (Echidna), a wide field (30 arcmin) corrector and a focal plane imager(FPI) used for controlling the positioner and for field acquisition. This paper presents an overview of the AAO shareof the FMOS project. It describes the technical infrastructure required to extend the single Echidna "spine" design to a
fully functioning multi-fiber instrument, capable of complete field reconfiguration in less than ten minutes. The
modular Echidna system is introduced, wherein the field of view is populated by 12 identical rectangular modules,
each positioning 40 science fibers and 2 guide fiber bundles. This arrangement allows maintenance by exchanging
modules and minimizes the difficulties of construction. The associated electronics hardware, in itself a significant
challenge, includes a 23 layer PCB board, able to supply current to each piezoelectric element in the module. The FPI
is a dual purpose imaging system translating in two coordinates and is located beneath the assembled modules. The FPI
measures the spine positions as well as acquiring sky images for instrument calibration and for field acquisition. An
overview of the software is included.
Keywords: astronomical instrumentation, fibers, piezo, fiber positioner, Subaru telescope, spectroscopy

1. GENERAL FEATURESThe Fiber Multi-Object Spectrograph (FMOS) for the prime focus of the Subaru telescope on Mauna Kea will provide
the first wide field multi-object near-infrared spectroscopic capability on an 8-m telescope1. The effort to design andbuild the FMOS instrument is shared amongst the Anglo-Australian Observatory, the University of Durham, Oxford
University, Rutherford Appleton Laboratory (RAL), the National Astronomical Observatory of Japan, Kyoto
University and the Subaru Telescope.
The 8.2m mirror of the Subaru telescope (Fig. 1) directs light to the prime focus, located about 15 m away. A threeelement prime focus corrector (Fig. 2) provides a 0.5° diameter field of view optimized for the near infrared.
A 400 fiber positioner, Echidna, sits above the corrector in the prime focus unit. Echidna represents a radical change inthe design of multi-fiber positioners. It was developed2 as an alternative to more traditional pick and place instrumentsthat could not position as many fibers in as small an area (400 in about 150 mm diameter). The Echidna positioner andfocal plane imager, used to determine the fiber positions, are described in detail later.
contacts: * pg@aao.gov.au;** amm@aao.gov.au;

phone + 61 2 93724845; fax + 61 2 93724860;
phone + 61 2 93724840; fax + 61 2 93724881

http://www.aao.gov.au

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At the top of the prime focus unit, the fibers
leaving Echidna connect with long fibers which
travel via the altitude axis to the two
spectrographs (200 fibers to each) (Fig. 1). The
connector is under development at the Universityof Durham and uses an array of accuratelyaligned GRIN (gradient index) lenses3. The
connector not only allows for detaching the prime
focus unit from the telescope but also provides ameans of changing the focal ratio from f/2 to f/5
before injection into the longest run of fibers. The
connector also provides for back-lighting the f/2
fibers as needed for controlling the positioning of
the Echidna spines. The fiber link, consisting of~20 km of optical fiber, will be permanently
installed on the telescope structure.
The 400 fibers feed two identical spectrographs
designed for faint spectral observations in thenear-infrared. Based on the OH-suppression
Fig. 1: CAD model of Subaru telescope, showing the locations
technique used in the Cambridge InfraRedof the prime focus unit, fiber routing, and the spectrographs.
Panoramic Astronomical Survey Spectrograph(CIRPASS), the spectrographs reduce the nightsky background emission by physically masking the atmospheric emission lines. The spectrographs have two
observing modes. The low resolution mode covers the wavelength range 0.9-1.8 µm in a single exposure at a resolutionof R~500. In the high resolution mode one quarter of the wavelength range is imaged at a resolution of R~2200. A
collaboration between RAL, the University of Oxford, and Kyoto University is designing and building thespectrographs1.
The FMOS spectrographs will be housed on a specially built platform located above the right-hand Nasmyth platform
as shown in Fig. 1. (Both the Nasmyth platforms of Subaru are already occupied).

2. PRIME FOCUS CORRECTOR
2.1 General features
The main prime focus corrector requirements were: good
imaging over the spectral range 0.9 to 1.8 µm; a flat telecentric focal surface; a final focal ratio > f/2; and a backfocus of at least 200 mm.
Although the Echidna design is adaptable to a curved focal
surface, a flat focal surface simplifies the attainment of
accurate focus of spine tips and mounting of the modules.
A telecentric focal surface aligns the chief ray with thefiber axis over the whole field, when the spines are at thecenters of their ranges, and thus minimizes inefficiency due
to misalignment of the telescope beam and the acceptancecone of the fiber.

Fig. 2. Sectioned view of prime focus corrector.

Mechanically, the corrector must fit within the largely preexisting prime focus unit (PFU) design and maintain aback focal distance of 200 mm to provide clearance for the
FPI and the Shack-Hartmann unit.

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2.2 Optical design

Fig. 3 Spot diagrams for wavelengths 0.9, 1.3, and1.8 µm. Circles are 100 µm diameter, the same as thefiber cores. The spots are for the field center and radii
enclosing 1/3, 2/3, and all the field area.

The corrector design produces images with rms radii
exceeding 20 µm only in the outer area of the
30 arcmin diameter field, for wavelengths of 0.9 to
1.8 µm. With allowance for seeing and for the
misalignment of the fiber axis with the telescope
pupil when a spine is tilted, the proportion ofradiation collected inside the 100µm diameter fibercore is affected very little by the optical aberrations.
The beam focal ratio after the corrector is f/2.1, while
the Subaru primary mirror is f/1.8. An earlier design
to feed visible wavelength as well as near infrared
spectrographs, included an atmospheric dispersion
corrector (ADC), but plans for optical spectrographs
were omitted, rendering an ADC unnecessary.
As shown in Fig. 2, the design incorporates three lenselements; all are of BSM51Y glass. The blank forthe first element, 600 mm diameter and deeply
curved, will be slumped to minimize the material tobe removed.

2.3 Mechanical structure
A simple welded thin wall shell structure has been adopted. Such tubular structures are inherently stiff, readily
fabricated and readily machined. It is also compact, which is required to fit the corrector into the prime focus unit. The
shell is made in two sections to facilitate welding and machining.
Each lens is mounted in its own metal cell and compliant pads are used to limit mounting stresses on the glass. The
cells are bolted to the shell so that alignment of the corrector may be made by working with the metal to metalinterfaces between shell and cells. Since the second lens is buried within the shell, the easily accessible first and third
lenses will be referred to it for alignment.
The corrector assembly is mounted via a thick aluminum adapter ring, visible in Fig. 2 near the level of the third lenselement. This adapter ring will be mounted on a translator (provided as part of the PFU) which translates the corrector
to compensate for deflection of the telescope structure. The mounting plane is some 350mm behind the center ofgravity, and an overhanging moment of 500 Nm will be exerted on the mount.

3. ECHIDNA FIBER POSITIONER: BASIC CONCEPT AND MECHANICAL DESIGN
3.1 Background
The area of the Subaru field is about 10 times less than for the 2 degree field (2dF) facility at the Anglo-Australian
Telescope prime focus. The required number of fibers is the same, so it was considered that the 2dF technique placement of magnetic buttons, carrying prisms and fibers, by a robot - was not practical. Instead a concept has beendeveloped in which each fiber is held in a spine, which is tilted so that its tip can be anywhere within a circle. For 400
fibers in a diameter of about 150mm, the pitch of fibers on a uniform triangular pattern is ~ 7 mm.
With 7 mm radius as the range for each spine, the success rate in allocating fibers to 400 targets randomly scatteredover the field is ~ 90%. An example of how a random field of 400 objects can be allocated with an Echidna instrument
is shown in Fig. 4. The large dots denote an unallocated target object and the small squares denote unallocated spines(with the exception of the 14 guide spines located in rows along both sides of the field of view). For spines that areallocated, an arrow indicates how the spine will reach its target object. In this test 33 out of 400 targets are unallocated-a success rate of ~92%. The detailed algorithms for allocating fibers to targets are described in Sec. 4.3.

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unallocated target
guide spines

unallocated spine

Fig. 4. Example of allocation of spines to 400 targets randomly scattered within the field. Arrow points are at targets,
tails are at spine centers. 33 unallocated spines and 33 missed targets are indicated.
With the f/2.1 beam, a misalignment of the fiber axis with the telescope optical axis, due to the spine’s tilt, of about
0.05 radian (roughly 10% of the beam diameter) is reckoned to be just acceptable. For 7 mm displacement this requiresthat the spine have a length of at least 140 mm.
3.2 Echidna spine construction
All Echidna science spines are identical. The spine and its components are illustrated in Fig. 5. Beginning at thecemented and polished optical fiber, a single spine consists of a stainless steel tapered tube cemented into a length ofcarbon fiber reinforced tube. The carbon fiber offers excellent stiffness to weight ratio, important for minimizing thespine sag. The tube is cemented into a stainless steel "pivot" ball bearing with a hole cut through its axis by electrical

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Fig. 5. Assembled spine inserted in mount (center); spine components (left); mount components (right).
discharge machining. As the spine must be balanced about the center of the pivot ball, a length of tungsten alloy tube isused for counterbalance. A small section of steel tube is cemented outside the carbon reinforced tube for fineadjustment of the balance. The optical fiber exits through the bore of the tungsten alloy counterweight. The spine
length, measured from the center of the pivot ball to the fiber tip, is 160 mm. (Note this is slightly longer than theminimum length of 140 mm derived above, giving an improved optical performance). Lengths greater than 160 mm
were not considered, primarily to limit the spine sag.
Each spine is inserted into a mount consisting of a near triangular section, rare earth magnet cemented to a quadrant
tube piezoelectric actuator (QTP). Three titanium nitride coated steel hemispheres, cemented to the surface of themagnet, provide the contact points for support of the spine pivot ball. As all the ball bearings are magnetic, the spine ispreloaded onto the contact points with a force much greater than the weight of the spine. The spine passes through thelength of the QTP actuator. As a spine must tilt about 2.7° to obtain a patrol radius of 7 mm, the length of the QTP isrestricted.

3.3 Spine dynamics
Each spine is driven by an actuator mount that, by a stick-slip ratcheting mechanism, is able to position the fiber tip towithin 10 µm of any position in the patrol area of the spine. The QTP is a radially polarized tube of piezoelectricmaterial. A single, continuous electrode is deposited onto the inner surface of the tube while on the outer surface there
are four electrically isolated quadrant electrodes. The material between a quadrant electrode and the inner electrodeexpands or contracts in the radial direction when a voltage is applied between the inner and outer electrodes. There is a

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corresponding change in the length of the material that causes the QTP to bend. Furthermore, if an opposite voltage isapplied across the opposing pair of electrodes, the bending is doubled. The magnitude of the bending is proportional tothe voltage amplitude. Orthogonal bending of the QTP is obtained by applying DC voltages across the remaining pairof quadrant electrodes.
To drive an Echidna spine, a repetitive sawtooth voltage is applied across the electrodes. This produces asymmetricalacceleration of the QTP that is vital to producing a net tilt of the spine tip from one sawtooth cycle to the next.
Referring to Fig. 6, the cycle can be summarized in three steps, though it should be noted that this is a simplified
explanation:

Fig. 6. Illustration of one cycle of spine drive (not to scale). Tilt isgreatly exaggerated.

1.

There is no applied voltage across theelectrode pair. The spine is parallel tothe axis of the QTP.

2.

The QTP bends slowly as the applied
voltage ramps up to the maximum
value. Friction between the ballbearings of the mount and spine
prevents the spine from sliding.

3.

The QTP rapidly returns to its central
position as the voltage decreases
quickly to the original value. The
mount acceleration overcomes thefriction at the contacts between theballs and the spine retains some net
tilt. A typical movement at the tip foreach cycle is about 60µm for thelargest voltage amplitude and about
10 µm with the small amplitude used
for fine adjustment.

When a particular spine tip travel is required, the number of voltage cycles is applied which, by previous calibration,
will result in the appropriate total tilt. However, variability in the step size necessitates iteration, first with coarse steps
and later with fine ones, to reach the target position with the required accuracy of 10 µm.
3.4 Modular design
The actuator bases are cemented into a rectangular stainless steel “module”, with each module carrying 42 actuators (2rows of 21). The Echidna positioner is constructed using 12 such modules, as shown in Fig. 7. The modular
arrangement eases the construction of the positioner and provides a practical method for replacing a damaged module
at the summit of Mauna Kea. The resulting rectangular array of spines overfills the circular field of view, such that
only 400 of the 480 science spines are used to acquire targets.
So as to reduce the reconfiguration time dramatically, the spines are driven in parallel. The same voltage and frequency
sawtooth signal, used to produce the spine movement, is sent to all spine actuators simultaneously. A series ofelectronic switches provides the method of switching input to individual spines on or off. The upper limit for thereconfiguration time for all 400 spines is 10 minutes, which, for this instrument, is limited by the fiber position
measurement system.
3.5 Fiber position measurement system
The fiber positions are determined using a Focal Plane Imager (FPI), which takes images of backlit fibers, a similar
concept to that used in the AAO 2dF positioner. The FPI consists of a telecentric lens coupled with a 2/3 inch format
video camera mounted on an X/Y stage, roughly 150 mm ahead of the focal plane as shown in Fig. 8. The imaging

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12 electronics
switching boards ateach side

Fig. 7: Modular design ofEchidna. The field of view iscovered with 12 modules,
each having 40 science spinesand 2 guide spines. Twosignal switching boards foreach module are located at
the sides of the unit.

main board
1 of 12 modules, partly
populated with spines
spinessystem is able to record centroids for only a small subset of the 400 spines, approximately 12 backlit fibers at a time.
Thus the FMOS field of view is split into 59 fields as shown in Fig. 9.
The FPI has another purpose; mapping the focal plane with a “sky” camera which is able to image 1-2 arcmin of sky.
This provides a convenient calibration tool for the instrument. Field distortion of the prime-focus corrector can bemapped with the camera. The likely candidate for the sky camera is a high sensitivity Watec video camera,
successfully tested recently on the AAT.

Y axis motor

sky camera

focal plane

spine camera
X axis motor

45° fold

Fig. 8: Focal Plane Imager (FPI) shown inverted forclarity. It has two cameras: a fiber imaging system
and a sky imager.
In this view, light from thetelescope comes from above.

Fig.9: FPI frames superimposed onto the FMOS field ofview; the locations of the science and guide spine home
positions along with the fixed fiducials are indicated.

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3.6 Auto-guiding
The Echidna instrument is responsible for fine-grained adjustments of the tracking of the telescope. This is achieved
with the use of seven guide spines on each side of the field, each spine having a bundle of seven fibers. The outputs
from these fibers are imaged onto a cooled CCD camera. Echidna’s autoguiding software will analyze the resulting
CCD images to determine appropriate corrections to the telescope azimuth and elevation and the instrument rotationand send them to the Subaru telescope control software.

4. ECHIDNA: ELECTRONIC AND SOFTWARE DESIGN
4.1 Electronics design
The electronics associated with driving a single Echidna spine are not difficult. All that is needed is a waveformgenerator, high voltage amplifier, high voltage (+/-150V) power supply, and interconnecting cabling. When one
considers driving 400 spines independently along two axes, the complexity increases. At the design stage theelectronics must be made practical, maintainable, and modular.
The method of driving the spines was one of the first design considerations. Ideally one would want to drive all of thespines simultaneously, thus reducing the total reconfiguration time and software complexity. This task should beaccomplished with minimal associated electronics. In theory, all of the spines can be positioned simultaneously by only
two amplifiers. A single drive signal is generated by the computer. The drive signal is composed of repeating sawtoothpulses. This signal is amplified by two amplifiers. One of the amplifiers has positive gain, and the other has negative
gain. A simple switching network is associated with each spine. This switching network selects between the positive
and negative drive signals, and it makes connection to the X or Y
electrode of the piezo tube. Thus each spine can be moved ineither axis and in either direction.
The above scheme has been implemented, although power
constraints made it more practical to use four amplifiers insteadof two. The amplifiers have been designed around Apex
operational amplifiers. The switching network was incorporatedusing Nais surface mount solid state relays.
The next design challenge was that of where to put all theelectronics. It was once assumed that all of the electronics would
be in a single cooled enclosure. This proved not to be practicalsince over 800 wires would be needed to connect the switching
network to the piezos. The large number of cables and connectors
would have made maintenance very difficult. Instead, theswitching electronics were designed as daughter cards which
mounted on each end of each piezo module, as shown in Fig. 7.
The switch cards are all identical and each controls one half
module. Now only two cables are needed between the electronic
enclosure and the Echidna platform. The first is for analog drive
signals and telemetry, and the second is for digital control
signals.
Fig. 10: Electronics units located above theIn addition the AAO must provide control electronics for the FPI,
Echidna positioner in the FMOS prime focus
cooled camera (used to image the guide fiber bundles), and forunit
the back-illumination of all fibers (science, guide and fiducials).
Much of this has been designed and, during the construction of
the prototype system, assembled and tested. A rendered drawing of the electronics packaging is shown in Fig. 10.

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4.2 Software overview
The Echidna instrument comprises a number of different software subsystems which are integrated together to form
part of the FMOS instrument. The Echidna instrument control software is responsible for a number of tasks which canbe broadly described as positioning each of the spines at the required position in preparation for an observation. This
software executes on a diskless (remotely booted) Linux PC located in the Subaru PFU (just behind the spines). The
control software is a mixture of low-level device drivers (written in C) and high-level control routines (written in C++).
In the following sections, we describe some key features of Echidna’s spine positioning software: the spine-to-object
allocation algorithm, the fiber-encoding (back-illumination) algorithm, and spine calibration methods.
4.3 Spine-to-Object allocation algorithm
Prior to an observation, a target field configuration has to be prepared. This is achieved using Echidna's spine-to-object
allocation software which accepts an input catalog of potential target objects and generates an optimal allocation foreach of the 400 science spines. The software must take into consideration many constraints and parameters such as:-

ensuring neighboring spines do not "cross".

-maximizing the alignment of spines with the incoming beams (increases light throughput).

-

soft priority (allows the Astronomer to indicate their preference for each target object in the event that not all
objects can be allocated).

-

minimizing the distance the spines must move (leads to faster configuration time).

-

allowance for atmospheric refraction effects and mean RA/dec to apparent RA/dec conversions.

The core algorithm of the spine-to-object allocation software uses a breadth-first search, common in many chessprograms. By starting with fibers adjacent to an unallocated object and successively altering the allocation of fibers
further and further from the unallocated object, it is often possible to free-up an existing allocated spine (by allocating
its object to another unallocated spine further afield) for use with the unallocated object. Empirical tests have shownthat searching to a depth of 7 (i.e. altering the allocation of up to 7 spines) can yield a near-optimal configuration. A
typical branching factor of 3 or 4 means that this software is very efficient and capable of running on most modern
Unix workstations.
Simulations with the allocation software have shown that for many random fields with 400 input targets an allocation
efficiency of 90% is achievable (an example is shown in Fig. 4). This leaves ~ 40 spines unallocated, of which mostwill be used for sky subtraction.
4.4 Configure fiber and back-illumination encoding
Once an allocation has been prepared using the spine-to-object allocation software, it can be downloaded to Echidna
where the positioner software determines how to move the spines to the required positions. This is an iterative processthat takes ~ 5 cycles. After each cycle, the positioner software uses the FPI and a back-illumination encoding pattern
for spine position feedback. The time taken for the FPI to move from one frame to the next (~ 1s) is a major element of
the reconfiguration time: around ten minutes for all 400 spines.
Driving a spine to any target position with a single set of x, y signals has an inherent inaccuracy of ~ 10%.
Consequently, after driving a spine, the positioner must determine the new position of the spine and calculate a newoffset to the target position, and drive the spine again. This process is repeated until the spine is within 10µm of thetarget position. This typically takes 3-4 cycles for a single spine, but a 5th cycle will usually be required when
configuring a full field.

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Fig. 11 Back-illumination encoding pattern used for the spines. (The arc denotes the Echidna field of view;the dots show the home positions of spines.) The 3 binary digits represent whether the LED is turned on (1) oroff (0) for the spine in each of the 3 frames.
To determine the position of a spine, it is back-illuminated and imaged using the spine camera on the FPI (Sec. 3.5).
The back-illumination procedure for the Echidna is more complex than for other fiber multi-object instruments
developed at the AAO (e.g. 2dF, 6dF, OzPoz). This complexity is necessary as Echidna must distinguish between
many spines in an image which can overlap in complex ways. To resolve the ambiguity of overlapping spines, eachspine is associated with a 3-bit number representing a back-illumination encoding pattern. As illustrated in Fig. 11,seven distinct encoding patterns are used.
To locate the positions of the spine tips, the fiber imaging camera on the FPI gantry is positioned to view a subset ofspines. Spines that could be located in the spine camera field-of-view are then back-illuminated three times according
to their encoding pattern and imaged (three times) by the spine camera. The control software then processes the threeframes and determines the position of all spines in the camera field-of-view.
4.5 Calibration of movement of individual spine
When sent an identical signal, the step sizes and directions of different spines are not identical. This is due to small
inherent physical differences between spines and the 3-hemisphere piezo mounts - causing unique individual
characteristics. Each spine has to be individually calibrated, to allow the control software to more accurately estimate
the driving signals required to position the spine. This indirectly improves the performance of the spines and reduces
the total field configuration time.
Additionally, subtle (non-predictable) temporal variations in the performance of individual spines cause small
repeatability errors in positioning. To smooth these errors, the Echidna positioning software maintains the calibration
database for each individual spine in (pseudo) real-time whilst configuring fields. This self-calibration mechanism
improves reliability and quickly detects misbehaving spines.
4.6 Avoiding spine collisions
The Echidna control software must ensure that spines do not collide with each other. A collision would not physicallyharm the spines, however, it would detract from the spine performance and could cause spines to become "crossed".
Crossed spines oppose each other in their direction of travel and prohibit accurate positioning. With up to 400 spines
being driven in parallel and each spine constrained to moving along 2 near-orthogonal axes, avoiding collisions is a
critical function of the control software.
The spine-to-object allocation software contains an algorithm to ensure that spines are not allocated to targets thatwould cause them to cross - this alleviates many of the potential causes of collision. However, there still remains thepotential for spines to collide when configuring a field. This largely stems from situations where spines are positioned
very closely to one another, or where spines must move past each other on their way to their target positions.

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Care is also taken to avoid collisions when configuring a new field. Driving spines from their position in an old field totheir position in a new field is dependant upon the sequence of fields being observed, which is not predictable with any
certainty. Currently, the control software blindly drives all spines to their home position before configuring a new field.
It is considered "blind" because the FPI is not used to determine the positions of the spines afterwards (it would take
too long) - they are assumed to be exactly in their home position when calculating the required offset to the target
position.

5. CURRENT STATUS
The AAO FMOS project is mid-way through the final design stage. As part of the preliminary design a single module,
half-filled with spines, was assembled together with a single-axis version of the FPI. The assembly and testing of the
prototype system, shown in Fig.12 and 13, was of great practical value to the project.

Fig. 12: Single-axis prototype of the FPI. The metal blocks replicate the expected loading on the X-axis motor.

Fig. 13:

Left: the half-filled prototype module. The LEDs for back-illuminating the fiber are to the right.
Right: a close-up of the half-filled module, showing the required packing density of the spines in Echidna.

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ACKNOWLEDGMENTS
The authors wish to thank all AAO members of staff for their continued support of the FMOS project, in particular
Dwight Horiuchi and Neal Schirmer for workshop support and Ed Penny for electronics support. Many thanks go to
Steve Lee of the Anglo-Australian Telescope for advice concerning the sky camera. The FMOS team acknowledges
the support received from Subaru and from Kyoto University, in particular from Toshinori Maihara, the PI for FMOS,
and from Masahiko Kimura, working on the prime focus unit design.

REFERENCES
1.

M. Kimura et al, “Fiber-Multi-Object Spectrograph (FMOS) for Subaru Telescope,” in Optical/IR Ground Based
Instrumentation, A. Moorwood, ed., Proc. SPIE 4841, (in press), 2002.

2.

P. Gillingham, S. Miziarsky, M. Akiyama and V. Klocke, “Echidna – a Multi-Fiber Positioner for the Subaru
Telescope,” in Optical and IR instrumentation and detectors, M. Iye, A. Moorwood, ed., Proc. SPIE 4008, pp.
1395-1403, 2000.

3.

I. J. Lewis, G. B. Dalton, I. A. Tosh, D. J. Robertson and G. J. Murray, “Developments on the UK FMOS project
for the Subaru Telescope,” in Optical/IR Ground Based Instrumentation, A. Moorwood, ed., Proc. SPIE 4841, (inpress), 2002.

SPIE USE 4841-184 (p.12 of 12) / Color: No / Format: Letter/ AF: Letter / Date: 2002-11-13 23:22:37