Space debris in Low Earth Orbit (LEO) is becoming an increasing threat to satellite and spacecraft. A reliable and cost effective method for detecting possible collisions between orbiting objects is required to prevent an exponential growth in the number of debris. Current RADAR survey technologies used to monitor the orbits of thousands of space debris objects are relied upon to manoeuvre operational satellites to prevent possible collisions. A complimentary technique, ground-based laser LIDAR (Light Detection and Ranging) have been used to track much smaller objects with higher accuracy than RADAR, giving greater prediction of possible collisions and avoiding unnecessary manoeuvring. Adaptive optics will play a key role in any ground based LIDAR tracking system as a cost effective way of utilising smaller ground stations or less powerful lasers. The use of high power and high energy lasers for the orbital modification of debris objects will also require an adaptive optic system to achieve the high photon intensity on the target required for photon momentum transfer and laser ablation. EOS Space Systems have pioneered the development of automated laser space debris tracking for objects in low Earth orbit. The Australian National University have been developing an adaptive optics system to improve this space debris tracking capability at the EOS Space Systems Mount Stromlo facility in Canberra, Australia. The system is integrated with the telescope and commissioned as an NGS AO system before moving on to LGS AO and tracking operations. A pulsed laser propagated through the telescope is used to range the target using time of flight data. Adaptive optics is used to increase the maximum range and number or targets available to the LIDAR system, by correcting the uplink laser beam. Such a system presents some unique challenges for adaptive optics: high power lasers reflecting off deformable mirrors, high slew rate tracking, and variable off-axis tracking correction. A low latency real time computer system is utilised to control the systems, with a Shack-Hartmann wavefront sensor and deformable mirror running at 1500 frames per second. A laser guide star is used to probe the atmosphere and the tracked debris object is used as a natural guide star for tip-tilt correction.
We report on the design, on-sky performance, and status of the FLAMINGOS-2 instrument – the fully-cryogenic facility
near-infrared imager and multi-object spectrograph for the Gemini 8-meter telescopes. FLAMINGOS-2 has a refractive
all-spherical optical system providing 0.18-arcsecond pixels and a 6.2-arcminute circular field-of-view on a 2048x2048-
pixel HAWAII-2 0.9-2.4 μm detector array. A slit/decker wheel mechanism allows the selection of up to 9 multi-object
laser-machined plates or 3 long slits for spectroscopy over a 6x2-arcminute field of view, and selectable grisms provide
resolutions from ~1300 to ~3000 over the entire spectrograph bandpass. FLAMINGOS-2 is also compatible with the
Gemini Multi-Conjugate Adaptive Optics system, providing multi-object spectroscopic capabilities over a 3x1-arcminute
field with high spatial resolution (0.09-arcsec/pixel). We review the designs of optical, mechanical, electronics,
software, and On-Instrument WaveFront Sensor subsystems. We also present the on-sky performance measured during
acceptance testing in 2009, as well as current status of the project and future plans.
The Giant Magellan Telescope presents a unique optical design with seven 8.4 m diameter primary mirrors
matched by seven adaptive secondary mirrors (ASM). The ASMs can be controlled in several dierent Adaptive
Optics (AO) observing modes coupled to the telescope . One of these AO systems, the Laser Tomography
Adaptive Optics (LTAO) system is currently in its preliminary design phase. The LTAO observing mode will
provide a Strehl ratio in H band of at least 30% over more than 20% of the sky and an ensquared energy in
K band of at least 40% in a 50 milli-arcsec spaxel over more than 50% of the sky. To achieve its performance
requirements, the LTAO observing mode uses six 20W Laser Guide Stars (LGS) with six order-60x60 Shack-Hartmann wavefront sensors. The LGSs are launched from three locations at the periphery of the telescope
primaries. A natural guide star (NGS) is used separately to measure tip-tilt, focus and low-bandwidth-low-order aberrations, as well as telescope segment piston. An open-loop controlled deformable mirror corrects the
o-axis NGS infrared wavefront. We give an update on the design of the LTAO WFSs, the LGS facility, the
on-instrument wavefront sensors and the tomography and control algorithms.
The Giant Magellan Telescope adaptive optics system will be an integral part of the telescope, providing laser guide star
generation, wavefront sensing, and wavefront correction to most of the currently envisioned instruments. The system
will provide three observing modes: Natural Guidestar AO (NGSAO), Laser Tomography AO (LTAO), and Ground
Layer AO (GLAO).
Every AO observing mode will use the telescope’s segmented adaptive secondary mirror to deliver a corrected beam
directly to the instruments. High-order wavefront sensing for the NGSAO and LTAO modes is provided by a set of
wavefront sensors replicated for each instrument and fed by visible light reflected off the cryostat window. An infrared
natural guidestar wavefront sensor with open-loop AO correction is also required to sense tip-tilt, focus, segment piston,
and dynamic calibration errors in the LTAO mode. GLAO mode wavefront sensing is provided by laser guidestars over
a ~5 arcminute field of view, and natural guidestars over wider fields. A laser guidestar facility will project 120 W of
589 nm laser light in 6 beacons from the periphery of the primary mirror. An off-axis phasing camera and primary and
secondary mirror metrology systems will ensure that the telescope optics remain phased.
We describe the system requirements, overall architecture, and innovative solutions found to the challenges presented by high-order AO on a segmented extremely large telescope. Further details may be found in specific papers on each of the observing modes and major subsystems.
We report on the design and status of the FLAMINGOS-2 instrument - a fully-cryogenic facility near-infrared imager
and multi-object spectrograph for the Gemini 8-meter telescopes. FLAMINGOS-2 has a refractive all-spherical optical
system providing 0.18-arcsecond pixels and a 6.2-arcminute circular field-of-view on a 2048×2048-pixel HAWAII-2
0.9-2.4 μm detector array. A slit/decker wheel mechanism allows the selection of up to 9 multi-object laser-machined
plates or 3 long slits for spectroscopy over a 6×2-arcminute field of view, and selectable grisms provide resolutions from
~1300 to ~3000 over the entire spectrograph bandpass. FLAMINGOS-2 is also compatible with the Gemini Multi-
Conjugate Adaptive Optics system, providing multi-object spectroscopic capabilities over a 3×1-arcminute field with
high spatial resolution (0.09-arcsec/pixel). We review the designs of optical, mechanical, electronics, software, and On-
Instrument WaveFront Sensor subsystems. We also present the current status of the project and future plans, including
on-sky delivery planned for late 2008.
The near-Infrared Multi-Object Spectrograph (IRMOS) for TMT is one of the most powerful astronomical instruments ever envisioned. The combination of the collecting area of TMT, the unique image-sharpening capabilities of the Multi-Object Adaptive Optics (MOAO) system, and the multiplexing advantage of the multi-object integral-field spectra provided by the IRMOS back-end make it capable of addressing some of the leading scientific challenges of the coming decades. Here we present an overview of one potential IRMOS concept and then focus on the MOAO system. In particular we will describe our concept for the laser and natural guide star wavefront sensors, deformable mirrors and the calibration system of MOAO. For each of these design elements, we describe the key trade studies which help define each subsystem. From results of our studies, we assemble a MOAO ensquared energy budget. We find that 50% of the energy is ensquared within the 50 milli-arcsecond spatial pixel of the IRMOS integral field units for a wavelength of 1.65μm. Given the requirements placed on the MOAO system to achieve this performance, large ensquared energies can be achieved with even finer plate scales for wavelengths longer than 1.5μm.
An On-Instrument Wavefront Sensor (OIWFS) designed, built and tested by the National Research Council of Canada (NRC) for the FLoridA Multi-object Imaging Near-IR Grism Observational Spectrometer (FLAMINGOS) is described. The University of Florida is building the FLAMINGOS-2 IR spectrograph for the Gemini Observatory as a near copy of the original multi-telescope FLAMINGOS instrument. NRC/HIA was subcontracted to build the OIWFS based on the Gemini Multi-Object Spectrograph (GMOS) design.
The FLAMINGOS-2 OIWFS patrols the bulk of the FLAMINGOS-2 field-of-view and will accept the Gemini f/16 input beam as well as the f/30 beam from the Gemini Multi-Conjugate Adaptive Optics (MCAO) system. The portion of the probe arm that enters the FLAMINGOS-2 field-of-view is cooled, to avoid contaminating the infrared images. The OIWFS uses the same CCD and CCD controller as was used on GMOS (e2v CCD39 and ARC GENII). Mechanically, the OIWFS is a modified version of the GMOS OIWFS. It comprises two stacked rotational stages, each operating on a single bearing. The top stage supports an optics package, which includes a lenslet array, pickoff arm and CCD. The optical design uses a four subaperture Shack-Hartmann lenslet array. The mechanism is controlled using EPICS based software that includes GUI engineering screens.
Test results showing the OIWFS to be fully compliant with design specifications are presented.
We report on the design and status of the FLAMINGOS-2 instrument - a fully-cryogenic facility near-infrared imager
and multi-object spectrograph for the Gemini 8-meter telescopes. FLAMINGOS-2 has a refractive all-spherical optical
system providing 0.18-arcsecond pixels and a 6.2-arcminute circular field-of-view on a 2048×2048-pixel HAWAII-2
0.9-2.4 μm detector array. A slit/decker wheel mechanism allows the selection of up to 9 multi-object laser-machined
plates or 3 long slits for spectroscopy over a 6×2-arcminute field of view, and selectable grisms provide resolutions from
~1300 to ~3000 over the entire spectrograph bandpass. FLAMINGOS-2 is also compatible with the Gemini Multi-
Conjugate Adaptive Optics system, providing multi-object spectroscopic capabilities over a 3×1-arcminute field with
high spatial resolution (0.09-arcsec/pixel). We review the designs of optical, mechanical, electronics, software, and On-
Instrument WaveFront Sensor subsystems. We also present the current status of the project, currently in final testing in
mid-2006.
We describe a simple and cost-effective concept for implementing a Ground Layer Adaptive Optics (GLAO) system on
Gemini that will feed all instruments mounted at the Cassegrain focus. The design concept can provide a GLAO
correction to any of the current or future seeing-limited optical or near-infrared Gemini instruments. The GLAO design
uses an adaptive secondary mirror and provides a significant upgrade to the current telescope acquisition-and-guide
system while reusing and building upon the existing telescope facilities and infrastructure.
This paper discusses the overall design of the GLAO system including optics, opto-mechanics, laser guide star facilities,
natural and laser guide stars wavefront sensors. Such a GLAO system will improve the efficiency of essentially all
observations with Gemini and also will help with scheduling since it virtually eliminates poor seeing.
We present an overview of the near-InfraRed Multi-Object Spectrograph (IRMOS) for the Thirty Meter Telescope, as developed under a Feasibility Study at the University of Florida and Herzberg Institute of Astrophysics. IRMOS incorporates a multi-object adaptive optics correction capability over a 5-arcminute field of regard on TMT. Up to 20 independently-selectable target fields-of-view with ~2-arcsec diameter can be accessed within this field simultaneously. IRMOS provides near-diffraction-limited integral field spectroscopy over the 0.8-2.5 μm bandpass at R~1,000-20,000 for each target field. We give a brief summary of the Design Reference science cases for IRMOS. We then present an overview of the IRMOS baseline instrument design.
We report on the design and status of the FLAMINGOS-2 instrument - a fully-cryogenic facility near-infrared imager and multi-object spectrograph for the Gemini 8-meter telescopes. FLAMINGOS-2 has a refractive all-spherical optical system providing 0.18-arcsecond pixels and a 6.2-arcminute circular field-of-view on a 2048x2048-pixel HAWAII-2 0.9-2.4 mm detector array. A slit/Dekker wheel mechanism allows the selection of up to 9 multi-object laser-machined plates or 3 long slits for spectroscopy over a 6x2-arcminute field of view, and selectable grisms provide resolutions from ~1300 to ~3000 over the entire spectrograph bandpass. FLAMINGOS-2 is also compatible with the Gemini Multi-Conjugate Adaptive Optics system, providing multi-object spectroscopic capabilities over a 3x1-arcminute field with high spatial resolution (0.09-arcsec/pixel). We review the designs of optical, mechanical, electronics, software, and On-Instrument WaveFront Sensor subsystems. We also present the current status of the project, midway through its construction phase in June 2004.
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