This PDF file contains the front matter associated with SPIE Proceedings Volume 11203, including the Title Page, Copyright Information, Table of Contents, Author and Conference Committee lists.

The ESO Extremely Large Telescope (ELT) has been in construction since 2014. In parallel with the construction of the telescope, ESO has entered into agreements with consortia in the ESO member states to build the first instruments for that telescope. To meet the telescope science goals, the ambitious instrument plan includes two instruments for first light: an optical to near-infrared integral field spectrograph with a dedicated adaptive optics system (HARMONI) and a near-infrared camera with simple spectrograph (MICADO) behind a multi-conjugate adaptive optics module (MAORY). The next instrument will be a mid-infrared imager and spectrograph (METIS). Plans to follow this first suite of instruments include a high-resolution spectrograph (HIRES) and a multi-object spectrograph (MOSAIC). Technology development is underway to prepare for building the ELT Planetary Camera and Spectrograph. An overview of the telescope and its instruments is given.

The Huntsman Telescope* is a wide field imager based on the successful Dragonfly Telescope concept.¹ It consists of an array of co-aligned telephoto DSLR lenses with cooled CCD cameras. The ten 140 mm apertures have a combined collecting area equivalent to a 0.5 m class telescope but have lower stray light levels than a typical telescope of this size.^{1, 2} Its primary purpose is low surface brightness imaging of nearby galaxies, and it also observes exoplanet transits and other optical transients.

There have been a dramatic increase in the number of optical and radio transient surveys due to astronomical transients such as gravitational waves and gamma ray bursts, however, there have been a limited number of wide-field infrared surveys due to narrow field-of-view and high cost of infrared cameras, we present two new wide-field near-infrared fully automated surveyors; Palomar Gattini-IR and the Dynamic REd All-sky Monitoring Survey (DREAMS). Palomar Gattini-IR, a 25 square degree J-band imager that begun science operations at Palomar Observatory, USA in October 2018; we report on survey strategy as well as telescope and observatory operations and will also providing initial science results. DREAMS is a 3.75 square degree wide-field imager that is planned for Siding Spring Observatory, Australia; we report on the current optical and mechanical design and plans to achieve on-sky results in 2020. DREAMS is on-track to be one of the first astronomical telescopes to use an Indium Galium Arsenide (InGaAs) detector and we report initial on-sky testing results for the selected detector package. DREAMS is also well placed to take advantage and provide near-infrared follow-up of the LSST.

The Giant Magellan Telescope Multi-object Astronomical and Cosmological Spectrograph (GMACS) is a first light instrument for the Giant Magellan Telescope (GMT). It will provide multi-object spectroscopy in wide wavelength coverage and wide field of view. The scientific objectives include exoplanet atmospheres, star formation and chemical evolution studies, galaxy assembly histories, and intergalactic medium tomography. The optical layouts are optimized to have high throughput in the natural seeing limit. In this presentation, we report the current status of the instrument development.

Maunakea Spectroscopic Explorer (MSE) is a dedicated multi-object spectroscopic facility that is a major upgrade to the Canada-France-Hawaii-Telescope (CFHT) on Maunakea, Hawaii, with a larger aperture and an expanded international partnership. MSE has completed its Conceptual Design Phase (CoDP) and is preparing for the upcoming Preliminary Design Phase.

The Multi-channel Photometric Survey Telescope (Mephisto) have a 1.6m primary mirror with 1.3 focal ratio, a 2degree field of view. Mephisto is capable of imaging the northern sky in three colors simultaneously. Its 0.7m secondary mirror is quite sensitive for alignment. The field dependent image quality of the misaligned Mephisto optics would be characterized as asymmetric, continuously varying and nonlinear with the misalignments. When the real-time field-PSF is measured from the astronomical images, the residual field-PSF of nominal optical design is defined as the goal of the merit function, the misaligned values of Mephisto secondary mirror can be calculated, by using the PSO (Particle swarm optimization) algorithm. The truth is field-PSF can be numerically expressed with ellipticity of the imaging stars or distribution of the ellipticity. However, for resolving the misalignment values, the stable field-PSF modes are needed, instead of random modes. PCA (Principal component analysis) algorithm is used for eliminating the random perturbations, such as turbulence.

The Starbug technology¹ developed by AAO-MQ allows fibre positioners to be built with large multiplexing capabilities. The Starbug robots are positionable individually and in parallel, which results in significant configuration time improvements over what can be achieved by single-arm pick and place robots. Their design allows the Starbugs to carry a complex payload, and their movement mechanism and vacuum adhesion to the instrument's glass field plate at the telescope's focal plane means that they can be used to position fibres on a non-planar surface.

One of the main challenges for the new generation of extremely large telescopes (ELT) such as the Giant Magellan Telescope (GMT) is apparent in their ability to phase the segments in their primary mirror. Due to the lack of viability of manufacturing enormous mirrors, these primary mirrors are composed of smaller segments, and therefore they must be phased. Prior to the full construction of GMT, there has been proposal to develop a small-scale laboratory testbed to reproduce elements of GMT’s design, major disturbances, and control systems. This would serve to reduce the risk in cost and time prior to commissioning.
The team at the Australian National University’s (ANU) Research School of Astronomy and Astrophysics (RSAA) have developed a design concept for such a miniature version, coined Pocket-GMT. Pocket-GMT is designed to simulate GMT’s segmented primary mirror as well as introduce aberrations and distortions similar to what GMT will experience. This would present an opportunity to optimize the functionality of GMT’s control software and wavefront sensors, and to demonstrate phasing within the laboratory prior to full-scale telescope implementation. Pocket-GMT would also be compatible with later GMT instrument prototypes, thus ensuring its usefulness going into the future.

Many areas of astronomical research rely on deep blue wide-field imaging. Mauna Kea enjoys the very best UV transparency from the ground and the Keck telescopes with 10 meter f/1.75 primaries are well suited to a prime focus camera with a large angular field. Swinburne University leads a proposal to provide a camera (KWFI, for Keck Wide Field Imager) that is optimized in the UV but works well to 1μm wavelength. Keck has interchangeable top end modules, of which one is now unused and easily capable of housing the required corrector lens and detector enclosure. This paper concentrates on details of the KWFI optical design.

ULTIMATE-Subaru is a next large facility instrument project at Subaru telescope. We will develop a 14x14 arcmin² wide-field near-infrared (1.0-2.5μm) imager and a multi-object spectrograph with the aid of a ground- layer adaptive optics system (GLAO), which will uniformly improve the seeing by a factor of 2 over a wide field of view up to ~20 arcmin in diameter. The expected spatial resolution by the GLAO correction is about 0.2 arcsec FWHM in K-band under moderate seeing conditions at Subaru telescope. ULTIMATE-Subaru will provide a unique capability to realize wide-field and high spatial resolution survey observations in near infrared in the era of TMT. In this paper, we introduce the project overview including the GLAO and near-infrared instrument conceptual design. We also describe the future wide-field strategy at Subaru telescope with ULTIMATE-Subaru together with HSC and PFS.

‘Emu’ is a compact wide-field photometer destined for a 6-month mission on the exterior of the International Space Station (ISS), commencing in 2021. Emu will undertake a sky survey in the 1.4 μm ‘water band’, as a method of estimating oxygen abundance in the atmospheres of cool stars down to a magnitude of m_AB≈13 (H-band).

GLUV is a balloon-based near UV survey telescope under development. The primary objective of GLUV is high- cadence observations of transient events such as early UV observations of supernova. The ozone layer absorbs a considerable amount of UV radiation, so it is important for a UV balloon telescope to achieve ight altitude above the ozone layer. The ozone layer density varies with respect to latitude, altitude and season. The structure and behaviour of ozone distribution is an important factor to be studied to account for astronomical ultraviolet observations. GLUV pathfinder is a spectrometer based system to identify the sky background at intended ight altitudes and atmosphere transmission GLUV will experience. In this presentation, we will present the design and development of the GLUV pathfinder system.

Ground-based infrared observations are often limited by atmospheric absorption and emission. Space-based instruments avoid this, but introduce unique technical challenges. We present the design of a flexible, compact, and cost-effective detector controller for space, based on commercial off-the-shelf components. Its architecture provides up to 50 configurable clock sequences and 16 biases, 32 16-bit video channels and several genera lpurpose ports. This allows for full control of CMOS detectors including Leonardo ‘SAPHIRA’ avalanche photodiode arrays (APD) which represent current state of the art in low-noise infrared imaging.

This paper presents a preliminary analysis of the first results we have obtained from the adaptive optics systems built for EOS 1.8 m telescope at Mount Stromlo. This presentation focuses on the single-camera stereo-SCIDAR for monitoring the atmospheric seeing. We briefly summarize the system, describe its on-sky performance during commissioning, compare results to numerical simulations and evaluate the remaining challenges going into the future.

Optimal transmission of pulsed laser energy to a target is essential for the maximization of reflected signal power in Debris Laser Ranging (DLR) systems. We describe the use of the PPPP measurement technique to allow compensation for both wavefront aberration, tip/tilt and errors arising from misalignment of the transmit and receive optical axes. This paper provides an update on the bistatic Wavefronts Obtained by Measuring Beam-profiles through Atmospheric Turbulence (WOMBAT) trial¹ conducted with the EOS Space Systems 1.8m DLR system² on Mt Stromlo, Australia, using an adjacent telescope to observe the 170 Hz PPPP intensity profiles.

Gemini Observatory has been awarded a major funding from the National Science Foundation to build a complete new state of the art multi-conjugate adaptive optics system for Gemini North. The system will be designed to provide an MCAO facility delivering close to diffraction limit correction in the near-infrared over a 2 arcminutes field of view and feed imaging and spectroscopic instruments. We present in this paper the results of the conceptual design phase with details on the new proposed laser guide star facilities and adaptive optics bench. We will present results on the performance simulation assessments as well as the developed selected science cases.

Large adaptive deformable mirror is becoming a trend for ground base telescope, at present almost all the large adaptive deformable mirrors in use are driven by voice coil, simultaneously the capacitive sensor is used as a feedback component. While the Eddy Current Sensor could have a lot of advantages over the capacitive one in large deformable mirror. In this research a prototype of 150mm deformable mirror is built, which is driven by 7 voice coil actuators, the ECSs are used in this prototype instead of capacitive ones. In the prototype experiment some standard low-order aberrations applied on the mirror could be corrected as expected, so it could be proved that the ECS could be used in large adaptive deformable mirror to take place of the capacitive one.

Large precision composite mirrors for space missions and telescopes can be heavy, massive and expensive to fabricate. In this work, the mass of the mirrors is reduced by using space approved carbon fiber reinforced polymer (CFRP) material and employing micro-fiber composite (MFC) actuators for aberration correction and phase manipulation in an active/adaptive optical mirror system. The carbon fiber mirror is fabricated with 16 layers of prepreg composite MTM44- 1/IMS65 carbon fiber and one layer of polishable resin. The layers are cured under pressure in an autoclave machine in a pressure and temperature-controlled environment. 2 different piezoelectric actuators, Push actuators and MFC actuators, are tested and the phase shift, form factor and surface deformation due to the active actuators are compared. Push actuators are the most common means of active optics. CFRP structure and surface deformation after actuator’s effect are investigated theoretically using finite element analysis with the aid of COMSOL software and by optical experiments.

From ground-based extremely large telescopes to small telescope arrays used for time domain astronomy, point spread function plays an important role both for scientific data post-processing and instrument performance estimation. In this paper, we propose a new method which can restore astronomical images and obtain the point spread function of the whole optical system at the same time. Our method uses simulated high resolution astronomical images and real observed blurred images to train a deep neural network (Cycle-GAN). The Cycle- GAN contains a pair of generative adversarial neural networks and each generative adversarial neural network contains a generator and a discriminator. After training, one generator (PSF-Gen) can learn the point spread function and the other generator (Dec-Gen) can learn the deconvolution kernel. We test our method with real observation data from solar telescope and small aperture telescopes. We find that the Dec-Gen can give promising restoration results for solar images and can reduce the PSF spatial variation for images obtained by smaller telescopes. Besides, we also find that the PSF-Gen can provide a non-parametric PSF model for short exposure images, which would then be used as prior model for PSF reconstruction algorithms in adaptive optics systems.

As confirmed exoplanets climb into the thousands, the era of exoplanets discovery is giving way to exoplanet characterization. The most desirable scenario is one where the exoplanet can be directly imaged. Direct imaging not only delivers orbital parameters, but also yields the chemical composition of the atmosphere. The potential for habitable zone exoplanets to exhibit biosignatures in such data from a visionary future instrument drives intense interest. However, this requires to simultaneously reach extremely high star-to-planet contrast (from 10⁴ to 10⁸) and extremely high angular resolution (around and below the diffraction limit). Accomplishing all this through the atmosphere blurred by turbulence remains a critical challenge, yet it is one that nulling interferometry in combination with extreme adaptive optics aims to meet. This technique overcomes the contrast problem by removing the starlight with destructive interference, permitting the faint light coming from the planet to remain. In this paper, we present the latest evolution of nulling interferometry instrumentation: the integrated- photonic nuller. It allows spatial filtering, multiple simultaneous baselines, simultaneous photometric channels and simultaneous measurement of the "nulled" signal (the light emitted from the planet after cancelling the starlight) as well as the "anti-nulled" signal (the channel containing the redirected starlight). Exploiting these fundamental optical principles, the delivery of imaging and differential spectroscopy of exoplanetary systems becomes possible. This paper describes a pathfinder that has implemented these ideas into a robust and compact photonic-chip platform known as the GLINT (Guided-Light Interferometric Nulling Technology) project.

Both the birth and death of a stellar system are areas of key scientific importance. Whether it's understanding the process of planetary formation in a star's early years, or uncovering the cause of the enormous mass-loss that takes place during a star's dying moments, a key to scientific understanding lies in the inner few AU of the circumstellar environment. Corresponding to scales of 10s of milli-arcseconds, these observations pose a huge technical challenge due to the high angular-resolutions and contrasts required. A major stumbling block is the problem of the Earth's own atmospheric turbulence. The other difficulty is that precise calibration is required to combat the extremely high contrast ratios and high resolutions faced. By taking advantage of the fact that starlight scattered by dust in the circumstellar region is polarized, differential polarimetry can help achieve this calibration. Spectral features can also be utilized.

Direct imaging of exoplanets is vital for understanding star system formation and the evolutionary behaviour of exoplanets at large orbits. Typically, imaging a star system to find an exoplanet requires significant attenuation of the host star’s high flux in order to detect the much weaker planetary light. The most common method to do this is coronagraphy, which blocks the starlight with an amplitude mask or a null inducing phase mask [1]. An alternative and attractive method is nulling interferometry where light from multiple telescopes are used to simultaneously form a high resolution image (or its Fourier components) and also to form a null in the vicinity of the host star, thereby attenuating it [2]. This has the advantage over coronagraphy that it is not limited to using a single telescope and is thus able to probe deeper into a star system by virtue of the higher resolution available by an interferometric array.

Direct detection of young giant planets can probe formation processes near the snow line, which is thought to be where giant planet formation is most likely. I will outline the scientific requirements for observational constraints on this process, and show that the minimum requirements from the ground can be achieved by a high contrast VLTI instrument (Hi-5/VIKiNG) operating within the 2-5 micron range, nulling starlight in a highly calibratable manner with a "Kernel Nuller". Understanding these processes in more depth will eventually require an instrument more sensitive than is possible from the ground, requiring a cooled space mission. I will describe a pathway for such a mission.

We will show the first results for a pupil remapping device with an integrated optics discrete beam combiner. Our expected monochromatic visibility functions are in good agreement with simulation and experiment. The device will be used for our upcoming on-sky tests at 4-m Willian-Herschel Telescope (WHT) in canary islands.

Ultrafast laser inscription is a technique to create low-loss three dimensional optical circuits within bulk dielectrics that is compatible with a wide range of optical materials. Its unique capabilities and the ability to rapid prototype and quickly iterate through different designs has made it exceptionally attractive for astrophotonics. This paper will summarize the basic aspects of ultrafast laser inscription and review recent progress in its application to astrophotonics, such as stellar interferometry.

Photonic ring resonator arrays used as notch filters are a promising novel solution to improve the signal-to-noise ratio of ground-based astronomical observations by suppressing OH emission lines in the near-infrared (NIR) wavelength range (0.9-2.5 μm). We aim to fabricate a series of ring resonators connected by a waveguide, each with its resonance wavelength and full-width-half-maximum (FWHM) matched with one of the OH emission lines.

In pursuit of miniaturization of spectrograph systems, various wavelength-dispersive technologies such as arrayed waveguide gratings (AWGs) [1] and stationary-wave integrated Fourier transform spectrographs (SWIFTS) [2] have been studied as possible candidates for practical implementations of compact, lightweight integrated spectrographs. Integrated echélle-grating (EG) based wavelength demultiplexers have been proposed as an alternative to AWGs for use as the main diffractive element in such a compact spectrograph [3]. Apart from the simple Rowland mount type, more sophisticated geometries, such as the perfect chirped grating (PCG) [4] and two-stigmatic-point gratings (SEG) [5] exist. In this work, we present the first planar integrated echélle grating based on SEG geometry and specifically designed for astronomical spectroscopy in the NIR range ~1500 nm to 1600 nm.

Narrow linewidth frequency-stabilized lasers are crucial in the research of optical clocks, precision spectroscopy, and tests of fundamental physics. Narrow linewidth laser with the wavelength of 698nm is essential in the development of Sr atom optical clocks that will be used for the frequency standards in the future. Here we report the recent development of ultra-stable lasers at national time service center, Chinese academy of sciences (NTSC). In the experiment, the frequency of an extended cavity diode laser at the wavelength of 698nm is stabilized to a reference cavity with a finesse of ~130000 using the Pound-Drever-Hall methods. The optical heterodyne beat between two independent lasers shows that the linewidth of one diode laser reaches 0.88Hz. The fractional frequency stability removed linear frequency shift is better than 2×10^-15.

The problem of atmospheric emission from OH molecules is a long standing problem for near-infrared astronomy. We are now close to solving this problem for the first time with the PRAXIS instrument. PRAXIS is a unique spectrograph which is fed by fibres that remove the OH background, and is optimised specifically to benefit from OH-Suppression. The OH suppression is achieved with fibre Bragg gratings, which were tested successfully on the GNOSIS instrument. The OH lines are suppressed by a factor of ~1000, leading to a reduction of the integrated background of a factor ≈9. A future upgrade to multicore fibre Bragg gratings will further increase this reduction. PRAXIS has had two commissioning runs, with a third commissioning run planned for July 2019, which will be presented at the conference. PRAXIS has a measured throughput of ≈20 %, demonstrating high efficiency in an OH suppression instrument for the first time. Science verification observations of Seyfert galaxies demonstrate the potential of OH suppression.

The Leonardo SAPHIRA is a HgCdTe linear avalanche photodiode array enabling high frame rate, high sensitivity, low noise, and low dark current imaging at near-infrared wavelengths. The ANU utilised the Leonardo SAPHIRA to develop a high cadence “Lucky Imager” which was successfully tested on sky at Siding Spring Observatory. The cryogenic electronics and cryostat were designed and built by the ANU. The cryostat was cooled with a compact Stirling cycle cryocooler with active vibration damping. Various detector control systems were tested, including an ESO 'NGC' system and also a 32 channel ARC SDSU Series III. Images were ultimately captured at a windowed frame rate of 2.2 kHz with the ESO NGC controller.

Cryocoolers have long been demonstrated to be a dominant source of vibration that have caused significant problems with AO systems on large telescopes. Existing large telescopes have already imposed strict vibration requirements on instruments in response to existing problems, and have often struggled to achieve them. As the field moves into the next generation telescopes with GMT, TMT and eELT, vibration requirements continue to get ever tighter. Instrument teams must respond to these more demanding requirements by careful selection of cryocoolers and thoughtful design of cryocooler mounts that are matched closely with the specific requirements of the telescope. As we will demonstrate in this paper there is not a one-size-fits-all solution for every instrument and every telescope. In this paper we demonstrate a general method of deriving the required performance for an anti-vibration mounts for cryocoolers. First we characterize a linear Stirling-type cryocooler as a source of vibration, and determine what compliant mounts would be required to make them acceptable for use on the VLT, GMT and TMT. Measurements are taken of vibration from a Cryotel GT linear Stirling cooler (with active vibration cancellation enabled). By comparing the measured vibration against the requirements of each telescope, we are able to determine the required transfer function and therefore the required spring rate for compliant mounts. The results indicate that while some simple rubber mounts may be sufficient for use with the VLT and TMT, but a compliant mount with natural frequency below 14 Hz must be used for GMT.

The Maunakea Spectroscopic Explorer (MSE) is a project to upgrade the 3.6-meter telescope and instrumentation of the Canada-France-Hawaii Telescope (CFHT) into a 11.25-meter telescope equipped with fiber-fed spectrographs dedicated to optical and near-infrared (NIR) spectroscopic surveys of millions of faint stars and galaxies. The current baseline for MSE is that of a prime focus, 10-meter effective aperture telescope feeding a bank of low and moderate spectral resolution spectrographs (LR, R~3000 and MR, R~6000) located on plat- forms, as well as high spectral resolution spectrographs (HR, R~20000-40000) located in the more stable pier of the telescope. The 1.5 square degree field of view of MSE will be populated with more than 3200 fibers of 100 diameter allocated to the LMR spectrographs, and more than 1000 fibers of 0.800 for the HR spectrographs. MSE completed its Conceptual Design Phase early in 2018 and is about to enter its Preliminary Design Phase.

The TAIAPAN instrument, being developed by the Australian Astronomical Optics (AAO) - Macquarie University, deploys 159 Starbug robots to position optical fibers on a 32 cm glass field plate on the focal plane of the 1.2 m UK-Schmidt telescope. The Starbug Routing algorithm created for the instrument allows the autonomous robots to reach accuracies of 0.5 arcsec of the assigned target. It employs a 3 stage tiered approach to find a collision-free path for Starbugs of increasing complexity and computational cost. For each Starbug a path is attempted using a direct simultaneous movement. If unsuccessful, subsequently more complex (and expensive) methods are tried until a valid path is found or the target is discarded. The system uses a MongoDB database to record and retrieve starbug locations and properties which allow in-situ re-routing to take place as well.

Hector^{1, 5} is the next dark-time instrument to be commissioned on the Anglo-Australian Telescope (AAT) and will include 21 IFUs called hexabundles^{2-4, 6} that will sit on the 2-degree top end. These hexabundles are bundles of fibres that are packed in a regular hexagonal array. They are built in sizes of 37, 61, 91, 127, and 169 fibres. The distribution of sizes of hexabundles was calculated to maximize the efficiency of the galaxy survey. The Hector hexabundles have been optimized for this instrument. Their regular hexagonal packing has been developed to improve data reduction accuracy, and the fibres have had a short length of their cladding etched in order to pack them as tightly as possible without reducing the optical quality of the devices.

The Gemini High-resolution Optical SpecTrograph (GHOST) is fed by an optical cable linking the telescope and environmentally stabilized spectrograph room. Telescope input is injected into integral field units that are translated along the focal surface by positioners. Each integral field unit serves as an image slicer partitioning the seeing limited image with the help of a hexagonal microlens array. An additional microlens array is used to inject light telecentrically into each fiber which maximizes the efficiency of the cable. Spectral measurements of the optical cable throughput are presented for the design wavelength range.

We discuss the extension of Laguerre-Gaussian (LG) mode sorters to higher spatial mode counts. LG mode sorters based on multi-plane light conversion were recently demonstrated. The device consist of a cascade of phase planes separated by free-space propagation which performs a spatial decomposition in the Laguerre-Gaussian basis. Whereby an incoming beam, described by a basis of N LG modes is mapped onto a Cartesian array of N Gaussian spots in the output plane. Each spot in the array contains a particular LG spatial component of the original beam. Previously, LG mode sorters have been demonstrated supporting as many as 325 modes using 7 planes. In this paper we present a design for a device that supports 1035 modes corresponding with the first 45 degenerate mode groups using 14 planes. At the centre wavelength, the device has a theoretical insertion loss of 2.10dB. The lowest loss LG mode is -1.65dB and the highest loss LG mode is -3.22dB. The average crosstalk over all modes is 12.75dB. The worst-case mode has a crosstalk of 9.20dB.

A few telescope projects plan to feed spectrographs through thousands of fibres, needing metrology accuracy for feedback of just a few μm. This generally requires accuracy at the metrology camera better than 0.1 arcsec, which can be frustrated by local seeing. With fiducials situated with the array of science fibres, seeing displacements can be calibrated, with accuracy depending on the fiducial spacing. Fiducials within the field usually require sacrificing science fibres but AAO’s positioner for MSE will take advantage of its tilting spines and a special but simple metrology camera to provide a multitude of fiducials within the field with no such sacrifice.

The MANIFEST Metrology Toolkit for GMT is set of in-house software tools to assist in the concept development and demonstration of the MANIFEST Metrology System. The Metrology Toolkit forms part of the ongoing MANIFEST pre- Concept Design Study conducted throughout 2019. The Metrology System is an essential component to provide precise location measurements of Starbugs over the focal-plane and relay this information to the positioning system. The goal of the Metrology System is to provide a positional measurement better than 30 microns (0.03 arcsecs) over a field-plate diameter of 1.2 m. The Metrology Toolkit is intended to be flexible to verify different implementations of the Metrology System.

Data Central is the AAO's flagship virtual observatory service, providing a central repository for Anglo-Australian Telescope (AAT) and UK Schmidt observations, survey-team derived data products and documentation. The system brings together catalogues, imaging, spectra and data cubes from dozens of surveys, providing an intuitive interface to query, explore and cross-match data sets of national and international significance. In this presentation, we brie y introduce the current services Data Central offers including: a publication-quality image cutout service, SQL query, a Single Object Viewer bringing together data products (IFS cubes, spectra, catalogues, photometry) from crossmatched sources across multiple surveys, VO services, schema browser and team-curated documentation via an in-house CMS.

We report results of the impact of fiber fusion splicing on Focal Ratio Degradation (FRD) and transmission loss of Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) fiber system. We test at f/5 input f-ratio conditions, the influence of fiber fusion splicing on FRD and transmission respectively in the laboratory. A precision test system was designed to reduce the system error and human error. The measurement accuracy of the system reaches micron scale. The fiber end surface was prepared by large core fiber cutter, grinder and fusion splicing workstation. The fiber surface roughness is less than 1 micron and the surface angle is less than 0.5°. By optimize the cutting and polish process, adjusted the fusion parameters, a satisfactory results of optical fiber fusion obtained in the laboratory. The maximum transmission increase caused by the fiber fusion is less than 3%, average value is about 1%; while the maximum FRD increase is about 0.12°. We repaired 14 damaged optical fibers of LAMOST fiber system by use fiber fusion method, and the average peak light intensity of the repaired fiber reaches more than 90% of the peak light intensity of the normal use fiber in action. Our results indicate that fiber fusion technology can be adopted for repair failure optical fiber, replace the fiber clips and astronomical instrument construction.

Frequency combs in a Silicon-Nitride-Microring resonator with an ultra-stable repetition frequency of 28.55 GHz were generated by means of an amplitude modulated pump laser at 1568.8 nm and compared to numerical calculation based on a modified Lugiato-Lefever-Equation. The comb spectrum at a power level of -40 dB with respect to the pump line spans a wavelength range of 70 nm.

SING is a near ultraviolet (NUV) spectrograph with a size close to 6U CubeSat form-factor. The spectrograph operates in the wavelength range from 1800 Å to 3000 Å, with a spectral resolution of 2 Å at the central wavelength. The spectrograph is intended to operate in low Earth orbit (LEO), with the primary goal to generate spectral maps of the regions of the sky covered within the field of view (FOV) of the instrument, constrained by the orbital inclination of the spacecraft. The payload consists of the telescope in Cassegrain configuration focusing the light on the slit, the corrector lens, the concave grating, the detector, and other required electronics components. As the event rate in the UV is low, the spectrograph employs a photon-counting detector because of its low noise performance. The payload uses FPGA as the main system controller to handle the detector readout, data compression and storage, health monitoring, and telemetry. In this work, we present the optical design and its analysis, along with a brief description of the architecture of electronic subsystems of the payload.

Entire Visible Sky (EnVisS) is one of the payload proposed for the ESA selected F-Class mission Comet Interceptor. The main aim of the mission is the study of a dynamically new comet, or an interstellar object, entering the inner solar system. The EnVisS camera is designed to capture the entire sky in some visible wavelength bands while the spacecraft passes through the comet's tail environment. EnVisS optical head is composed of a fisheye lens with a field of view of 180° x 40° coupled with an imaging detector equipped with both band-pass and polarimetric filters. Very wide angle lens, as a fisheye, must be necessarily anamorphic, i. e. its focal length must change along the field of view, in order to fit a finite-size imaging detector. This anamorphic distortion is introduced by the optical designer, depending on the desired applications. Each possible distortion bring along different field of view mapping and this must be taken into account by the scientific/metrological user, because the plate scale is variable along the focal plane. To obtain useful scientific information from fisheye images (astrometry, flux calibration and brightness measurements), a precise determination of the mapping function has to be accurately determined. In this paper we describe the expected distortion map of the EnVisS camera.

Precise wavelength calibration is a critical issue for high-resolution spectroscopic observations. The ideal calibration source should be able to provide a very stable and dense grid of evenly distributed spectral lines of constant intensity. A new method which satisfies all mentioned conditions has been developed by our group. The approach is to actively measure the exact position of a single spectral line of a Fabry-Perot etalon with very high precision with a wavelength-tuneable laser and compare it to an extremely stable wavelength standard. The ideal choice of standard is the D2 absorption line of Rubidium, which has been used as an optical frequency standard for decades. With this technique, the problem of stable wavelength calibration of spectrographs becomes a problem of how reliably we can measure and anchor one etalon line to the Rb transition. In this work we present our self-built module for Rb saturated absorption spectroscopy and discuss its stability.

Fiber modal noise is a performance limiting factor in high-precision radial velocity measurements with multi-mode fiber fed high-resolution spectrographs. Traditionally, modal noise is mitigated by agitating the fiber, this way redistributing the light that propagates in the fiber over many different modes. However, in case of fibers with only a limited number of modes, e.g. at near-infrared wavelengths or in adaptive-optics assisted systems, this method becomes very inefficient. The strong agitation that would be needed stresses the fiber and can lead to focal ratio degradation. As an alternative approach, we propose to use a classic optical double scrambler and to rotate the scrambler’s first fiber end during each exposure. Because of the rotating illumination pattern of the scrambler’s second fiber, the modes that are excited vary continuously. This leads to very efficient averaging of the modal pattern at the fiber exit and to a strong reduction of modal noise. In this contribution, we present a prototype design and first laboratory results of the rotating double scrambler.

Near space usually refers to the earth space with a height of about 20-100 km. It is a highly interdisciplinary field involving atmospheric physics, space physics, plasma physics, photochemistry, solar and geosciences, Geosciences and life sciences. The development and utilization of near space is far less than that of traditional airspace and satellite orbital space. Near space usually corresponds to areas where traditional airplanes are difficult to fly and satellites are not easy to detect. Compared with the middle and lower atmosphere and higher ionosphere and outer space, there has been a lack of systematic and efficient observers in the near space for a long time. Objectively, near space has become a weak point of human's understanding of the whole earth's space.