CHEOPS (CHaracterizing ExOPlanets Satellite) is an ESA Small Mission, planned to be launched in early 2019 and whose main goal is the photometric precise characterization of the radii of exoplanets orbiting bright stars (V<12) already known to host planets. The telescope is composed by two optical systems: a compact on-axis F/5 Ritchey-Chrétien, with an aperture of 320 mm and a Back-End Optics, reshaping a defocused PSF on the detector. In this paper we describe how alignment and integration, as well as ground support equipment, realized on a demonstrator model at INAF Padova, evolved and were successfully applied during the AIV phase of the flight model telescope subsystem at LEONARDO, the Italian industrial prime contractor premises.
SHARK-NIR is one of the forthcoming instruments of the Large Binocular Telescope second generation instruments. Due to its coronagraphic nature, coupled with low resolution spectroscopy capabilities, it will be mainly devoted to exoplanetary science, but its FoV of 18 x 18 arcsec and very high contrast imaging capabilities will allow to exploit also other intriguing scientific cases. The instrument has been conceived and designed to fully exploit the exquisite adaptive optics correction delivered by the FLAO module, which will be improved with the SOUL upgrade, and will implement different coronagraphic techniques, with contrast as high as 10-6 up to 65 mas from the star. Despite the wavelength range of SHARK-NIR is 0.96-1.7 um, the instrument is designed to work in synergy with SHARK-VIS and with LMIRcam, on board of LBTI. The contemporary acquisition from these instruments will extend the wavelength coverage from M band down to the visible radiation. The physical location of the instrument, at the entrance of LBTI, imposes dimensional constraints to the instrument, which had been kept very compact. The folded optical design includes more than 50 optical elements, among which 4 Off-Axis Parabolas, 1 Deformable Mirror for the compensation of the Non Common Path Aberrations from the FLAO Wavefront Sensor, 2 detectors and 3 different kinds of coronagraph: Gaussian Lyot, Shaped Pupil and Four Quadrant Pupil Mask. Most of these optics are located onto an optical bench 500 x 400 mm, which makes SHARK-NIR an extremely dense instrument. This, together with the presence of 4 off-axis parabolas and of coronagraphs, such as the Four Quadrant, poorly tolerant to misalignments, requires a careful alignment and test phase, which needs the fine adjustement of many hundreds of degrees of freedom. We will give here an overview of the opto-mechanical layout of SHARK-NIR and of the identified alignment procedure, mostly optical, planned to take place in 2018.
CHEOPS is the first small class mission adopted by ESA in the framework of the Cosmic Vision 2015-2025. Its launch is foreseen in early 2019. CHEOPS aims to get transits follow-up measurements of already known exo-planets, hosted by near bright stars (V<12). Thanks to its ultra-high precision photometry, CHEOPS science goal is accurately measure the radii of planets in the super-Earth to Neptune mass range (1<Mplanet/MEarth<20). The knowledge of the radius by transit measurements, combined with the determination of planet mass through radial velocity techniques, will allow the determination/refinement of the bulk density for a large number of small planets during the scheduled 3.5 years life mission. The instrument is mainly composed of a 320 mm aperture diameter Ritchey-Chretien telescope and a Back End Optics, delivering a de-focused star image onto the focal plane. In this paper we describe the opto-thermo-mechanical model of the instrument and the measurements obtained during the opto-mechanical integration and alignment phase at Leonardo company premises, highlighting the level of congruence between the predictions and measurements.
Laser Guide Stars are, in spite of their name, all but “stars”. They do not stand at infinite distance, neither on a plane. If fired from the side of a large telescope their characteristics as seen from various points on the apertures changes dramatically. As they extend in a 3D world, there is need of a WFS that deploy in a similar 3D manner, in the conjugated volume, resembling the approach that MCAO required long time ago to overcome the usual limitations of conventional AO. We describe a class of a novel kind of WFS that employ a combination of refraction and reflection, such that they can convey the light from an LGS into a limited number of pupils, making the device compact, doable with a single piece of glass, and able to feed a minimum sized format detector where the information is collected maximizing the information depending from which part of the LGS the light is coming from, and on which portion of the telescope aperture the light is landing. They represent, in our opinion, the best-known adaptation of the pyramid WFS for NGS to the LGS world. As in the natural reference case the practical advantages come along with some fundamental advantages. Being a pupil plane WFS with the perturbator placed on the (3D) loci of focus of the various portions of the source of light they have the potentiality to extend WFS to a number of issues, including the ability to sense the islands effect, where non-contiguous portions of the main apertures are optically displaced. Further to their description and the main recipes we speculate onto possible variations on cases where the LGS is fired from the back of the secondary mirror and we exploit some potential features when implementing onto an extremely large aperture.
As the deep field surveys strategy represents a well popular way to study the cosmology and the formation and evolution of galaxies, we investigated how the new generation of extremely large telescopes (ELTs) will perform in this field of research. Our simulations, which combine a number of technical, tomographic and astrophysical information, take advantages of the Global-MCAO approach, a well demonstrated method that can be applied in absence of laser guide stars because it exploits only natural references. A statistics of the expected performance in a sub-sample of 22 well-known surveys are presented here.
We present a new testing facility hosted at the Coude focus of the INAF-Padova Copernico Telescope, a project carried on within the ADaptive Optics National Italian laboratories - ADONI. A permanent laboratory for on-sky experimentation accessible to the AO community, with the aim of hosting visiting multi-purpose instrumentation that may be directly tested on sky. We will give an overview of the activities carried on, describing the refurbishment activities at the hosting structure that allowed the opening of the facility: the implementation of the opto-mechanical train down to the Coude focus, and the creation of the laboratory. This facility provides a powerful scientific and technical test bench for new instrumental concepts, which may eventually be incorporated later in the next generation ELTs telescopes.
SHARK-NIR is a coronagraphic camera that will be implemented at the Large Binocular Telescope. SHARK-NIR will offer extreme AO direct imaging capability on a field of view of about 18" x 18", and a simple coronagraphic spectroscopic mode offering spectral resolution ranging from 100 to 700. In order to meet the SHARK-NIR main scientific driver, i.e., searching for giant planets on wide orbits, a high contrast is necessary. A set of corona-graphic masks were tested, we selected the best performing configurations for the instrument: the Gaussian-Lyot coronagraph, a Shaped Pupil (SP) with 360° of discovery space and two SP masks with asymmetric detection area but with a small inner working angle and the Four Quadrant phase mask. Many simulations were performed to obtain the performance in different atmospheric conditions, including seeing variations, by using magnitude guide star from R = 8 to R = 14 and testing also the jitter value. These changes in simulation parameters reflected a variation in the corona-graphic performance. We analysed the simulation images by searching the best post processing to obtain the best performance for the coronagraph, moreover, we have taken account the fact that using, in the ADI technique, small subsets to generate the reference PSF can help attenuating the speckle noise, but it also results in a growing risk of planet removal if not enough field rotation occurs in the subset itself. We analysed the results after this effect is included, so the performances were shown as function of the Strehl Ratio condition to obtain mass and age limits for the detection of the planets.
The Son Of X-Shooter (SOXS)1 is a medium resolution spectrograph (R ~ 4500) proposed for the ESO 3.6m NTT. We present the optical design of the UV-VIS arm of SOXS which employs high efficiency ion-etched gratings used in first order (m = 1) as the main dispersers. The spectral band is split into four channels which are directed to individual gratings, and imaged simultaneously by a single three-element catadioptric camera. The expected throughput of our design is > 60% including contingency. The SOXS collaboration expects first light in early 2021. This paper is one of several papers presented in these proceedings<sub>2-10</sub> describing the full SOXS instrument.
SOXS (Son of X-shooter) is a wide band, medium resolution spectrograph for the ESO NTT with a first light expected in early 2021. The instrument will be composed by five semi-independent subsystems: a pre-slit Common Path (CP), an Acquisition Camera (AC), a Calibration Unit (CU), the NIR spectrograph, and the UV-VIS spectrograph. In this paper, we present the mechanical design of the subsystems, the kinematic mounts developed to simplify the final integration procedure and the maintenance. The concept of the CP and NIR optomechanical mounts developed for a simple pre- alignment procedure and for the thermal compensation of reflective and refractive elements will be shown.
We present the NIR spectrograph of the Son Of XShooter (SOXS) instrument for the ESO-NTT telescope at La Silla (Chile). SOXS is a R~4,500 mean resolution spectrograph, with a simultaneously coverage from about 0.35 to 2.00 μm. It will be mounted at the Nasmyth focus of the NTT. The two UV-VIS-NIR wavelength ranges will be covered by two separated arms. The NIR spectrograph is a fully criogenic echelle-dispersed spectrograph, working in the range 0.80- 2.00 μm, equipped with an Hawaii H2RG IR array from Teledyne, working at 40 K. The spectrograph will be cooled down to about 150 K, to lower the thermal background, and equipped with a thermal filter to block any thermal radiation above 2.0 μm. In this poster we will show the main characteristics of the instrument along with the expected performances at the telescope.
An overview of the optical design for the SOXS spectrograph is presented. SOXS (Son Of X-Shooter) is the new wideband, medium resolution (R>4500) spectrograph for the ESO 3.58m NTT telescope expected to start observations in 2021 at La Silla. The spectroscopic capabilities of SOXS are assured by two different arms. The UV-VIS (350-850 nm) arm is based on a novel concept that adopts the use of 4 ion-etched high efficiency transmission gratings. The NIR (800- 2000 nm) arm adopts the ‘4C’ design (Collimator Correction of Camera Chromatism) successfully applied in X-Shooter. Other optical sub-systems are the imaging Acquisition Camera, the Calibration Unit and a pre-slit Common Path. We describe the optical design of the five sub-systems and report their performance in terms of spectral format, throughput and optical quality. This work is part of a series of contributions<sup>1-9</sup> describing the SOXS design and properties as it is about to face the Final Design Review.
SOXS (Son of X-Shooter) will be the new medium resolution (R~4500 for a 1 arcsec slit), high-efficiency, wide band spectrograph for the ESO-NTT telescope on La Silla. It will be able to cover simultaneously optical and NIR bands (350-2000nm) using two different arms and a pre-slit Common Path feeding system. SOXS will provide an unique facility to follow up any kind of transient event with the best possible response time in addition to high efficiency and availability. Furthermore, a Calibration Unit and an Acquisition Camera System with all the necessary relay optics will be connected to the Common Path sub-system. The Acquisition Camera, working in optical regime, will be primarily focused on target acquisition and secondary guiding, but will also provide an imaging mode for scientific photometry. In this work we give an overview of the Acquisition Camera System for SOXS with all the different functionalities. The optical and mechanical design of the system are also presented together with the preliminary performances in terms of optical quality, throughput, magnitude limits and photometric properties.
SOXS will be a unique spectroscopic facility for the ESO NTT telescope able to cover the optical and NIR bands thanks to two different arms: the UV-VIS (350-850 nm), and the NIR (800-1800 nm). In this article, we describe the design of the visible camera cryostat and the architecture of the acquisition system. The UV-VIS detector system is based on a e2v CCD 44-82, a custom detector head coupled with the ESO continuous flow cryostats (CFC) cooling system and the NGC CCD controller developed by ESO. This paper outlines the status of the system and describes the design of the different parts that made up the UV-VIS arm and is accompanied by a series of contributions describing the SOXS design solutions (Ref. 1–12).
SOXS (Son Of X-Shooter) is a unique spectroscopic facility that will operate at the ESO New Technology Telescope (NTT) in La Silla from 2021 onward. The spectrograph will be able to cover simultaneously the UV-VIS and NIR bands exploiting two different arms and a Common Path feeding system. We present the design of the SOXS instrument control electronics. The electronics controls all the movements, alarms, cabinet temperatures, and electric interlocks of the instrument. We describe the main design concept. We decided to follow the ESO electronic design guidelines to minimize project time and risks and to simplify system maintenance. The design envisages Commercial Off-The-Shelf (COTS) industrial components (e.g. Beckhoff PLC and EtherCAT fieldbus modules) to obtain a modular design and to increase the overall reliability and maintainability. Preassembled industrial motorized stages are adopted allowing for high precision assembly standards and a high reliability. The electronics is kept off-board whenever possible to reduce thermal issues and instrument weight and to increase the accessibility for maintenance purpose. The instrument project went through the Preliminary Design Review in 2017 and is currently in Final Design Phase (with FDR in July 2018). This paper outlines the status of the work and is part of a series of contributions describing the SOXS design and properties after the instrument Preliminary Design Review.
SOXS (Son Of X-Shooter) will be a spectrograph for the ESO NTT telescope capable to cover the optical and NIR bands, based on the heritage of the X-Shooter at the ESO-VLT. SOXS will be built and run by an international consortium, carrying out rapid and longer term Target of Opportunity requests on a variety of astronomical objects. SOXS will observe all kind of transient and variable sources from different surveys. These will be a mixture of fast alerts (e.g. gamma-ray bursts, gravitational waves, neutrino events), mid-term alerts (e.g. supernovae, X-ray transients), fixed time events (e.g. close-by passage of minor bodies). While the focus is on transients and variables, still there is a wide range of other astrophysical targets and science topics that will benefit from SOXS. The design foresees a spectrograph with a Resolution-Slit product ≈ 4500, capable of simultaneously observing over the entire band the complete spectral range from the U- to the H-band. The limiting magnitude of R~20 (1 hr at S/N~10) is suited to study transients identified from on-going imaging surveys. Light imaging capabilities in the optical band (grizy) are also envisaged to allow for multi-band photometry of the faintest transients. This paper outlines the status of the project, now in Final Design Phase.
SOXS (Son Of X-Shooter) is a new spectrograph for the ESO NTT telescope, currently in the final design phase. The main instrument goal is to allow the characterization of transient sources based on alerts. It will cover from near-infrared to visible bands with a spectral resolution of R ∼ 4500 using two separate, wavelength-optimized spectrographs. A visible camera, primarily intended for target acquisition and secondary guiding, will also provide a scientific “light” imaging mode. In this paper we present the current status of the design of the SOXS instrument control software, which is in charge of controlling all instrument functions and detectors, coordinating the execution of exposures, and implementing all observation, calibration and maintenance procedures. Given the extensive experience of the SOXS consortium in the development of instruments for the VLT, we decided to base the design of the Control System on the same standards, both for hardware and software control. We illustrate the control network, the instrument functions and detectors to be controlled, the overall design of SOXS Instrument Software (INS) and its main components. Then, we provide details about the control software for the most SOXS-specific features: control of the COTS-based imaging camera, the flexures compensation system and secondary guiding.
Son of X-Shooter (SOXS) will be a high-efficiency spectrograph with a mean Resolution-Slit product of 4500 (goal 5000) over the entire band capable of simultaneously observing the complete spectral range 350-2000 nm. It consists of three scientific arms (the UV-VIS Spectrograph, the NIR Spectrograph and the Acquisition Camera) connected by the Common Path system to the NTT and the Calibration Unit. The Common Path is the backbone of the instrument and the interface to the NTT Nasmyth focus flange. The light coming from the focus of the telescope is split by the common path optics into the two different optical paths in order to feed the two spectrographs and the acquisition camera. The instrument project went through the Preliminary Design Review in 2017 and is currently in Final Design Phase (with FDR in July 2018). This paper outlines the status of the Common Path system and is accompanied by a series of contributions describing the SOXS design and properties after the instrument Preliminary Design Review.
Son Of X-Shooter (SOXS) is the new instrument for the ESO 3.5 m New Technology Telescope (NTT) in La Silla site (Chile) devised for the spectroscopic follow-up of transient sources. SOXS is composed by two medium resolution spectrographs able to cover the 350-2000 nm interval. An Acquisition Camera will provide a light imaging capability in the visible band. We present the procedure foreseen for the Assembly, Integration and Test activities (AIT) of SOXS that will be carried out at sub-systems level at various consortium partner premises and at system level both in Europe and Chile.
PLATO (Planetary Transits and Oscillations of stars) is a new space telescope selected by ESA to detect terrestrial exoplanets in nearby solar-type stars. The telescope is composed by 26 small telescopes to achieve a large instantaneous field of view. INAF-OAPD is directly involved in the optical design and in the definition and testing of the alignment strategy. A prototype of the Telescope Optical Unis (TOU) was assembled and integrated in warm condition (room temperature) and then the performance is tested in warm and cold temperature (-80C). The mechanical structure of the TOU is representative in terms of thermal expansion coefficient and Young's modulus with respect to the actual one. A dedicated GSE (Ground Support Equipment) is used to manipulate the lenses. By co-align an interferometer and a laser with respect to the center of the third CaF2 lens, a several observables references are used to define the position and tilt of the chief ray. The total procedure tolerances for every lens is 30'' in tilt, between 15-40 μm for focus and 22 μm for decentering and the total error budget of the optical setup bench is below this requirement. In this paper, we describe the AIV procedure and test performed on the prototype of the TOU in the INAF laboratory.
PLATO (PLAnetary Transits and Oscillation of stars) is the ESA Medium size dedicated to exo-planets discovery, adopted in the framework of the Cosmic Vision program. The PLATO launch is planned in 2026 and the mission will last at least 4 years in the Lagrangian point L2. The primary scientific goal of PLATO is to discover and characterize a large amount of exo-planets hosted by bright nearby stars, constraining with unprecedented precision their radii by mean of transits technique and the age of the stars through by asteroseismology. By coupling the radius information with the mass knowledge, provided by a dedicated ground-based spectroscopy radial velocity measurements campaign, it would be possible to determine the planet density. Ultimately, PLATO will deliver the largest samples ever of well characterized exo-planets, discriminating among their ‘zoology’. The large amount of required bright stars can be achieved by a relatively small aperture telescope (about 1 meter class) with a wide Field of View (about 1000 square degrees). The PLATO strategy is to split the collecting area into 24 identical 120 mm aperture diameter fully refractive cameras with partially overlapped Field of View delivering an overall instantaneous sky covered area of about 2232 square degrees. The opto-mechanical sub-system of each camera, namely Telescope Optical Unit, is basically composed by a 6 lenses fully refractive optical system, presenting one aspheric surface on the front lens, and by a mechanical structure made in AlBeMet.
We produced a "toy-model" of one Telescope Optical Unit of PLATO, the Medium sized mission selected by ESA to fly
in 2024. This is a six lenses dioptric very wide field camera with a window in front to take care of radiation impact on
the first lens whose optical glass cannot be replaced with a radiation hardened one. The main aim of this project is just to
produce a "cool" model for display purposes, in which one can "explore" the details of the inside through some openings
in the tube, in order to visually inspect some of the fine details of the opto-mechanics. While its didactic and advertising
role is out of doubt, during its construction we realized that some interesting outcome can be of some relevance for the
project itself and that some findings could be useful, in order to assess the ability of producing with the same technology
some (of course of much more modest quality) optical systems. In this context, we immediately dropped the option of
producing the lenses with opaque material painted with a color resembling a refractive material (like blue for instance)
and decided to actually produce them with transparent plastic. Furthermore the surfaces are then finely polished in order
to give them basic optical properties. Such an optical system has only very coarsely the converging properties of the
original nominal design for a number of reasons: the refractive indexes are not the nominal ones, the quality of the
surfaces and their nominal values are only roughly, within a few percent, the targeted one, and the way the surfaces are
built up makes them prone to some diffraction effects. However, the bulk of the lens and the surface roughness will give
a large magnification of the scattering effects that will be experienced, at a much lower level, on the actual flight model.
We investigated through propagation of a laser beam and by digital camera the main stray light modes that this toymodel
offers. In other words, the model amplifies, to a large extent, the negative bulk scattering and spurious reflection
just because surfaces and materials are orders of magnitude rougher that the intended ones. Even if this did not allow to
attempt to make any quantitative measurement, in order to scale down to the actual one, we used it to look
out independently for the main sources of stray light and we compared them with the one discussed by the optical design
team, obtained using professional ray tracing code. Finally, we point out some of the technicalities used in the design
to mimic the finest mechanical elements that cannot be safely incorporate in the final design and to produce pieces of
size much larger than the maximum volume allowed by our 3D printer in a single shot.
The project PLAnetary Transits and Oscillations of stars (PLATO) is one of the selected medium class (M class)
missions in the framework of the ESA Cosmic Vision 2015-2025 program. The mean scientific goal of PLATO is the
discovery and study of extrasolar planetary systems by means of planetary transits detection. The opto mechanical
subsystem of the payload is made of 32 normal telescope optical units (N-TOUs) and 2 fast telescope optical units (FTOUs).
The optical configuration of each TOU is an all refractive design based on six properly optimized lenses. In the
current baseline, in front of each TOU a Suprasil window is foreseen. The main purposes of the entrance window are to
shield the following lenses from possible damaging high energy radiation and to mitigate the thermal gradient that the
first optical element will experience during the launch from ground to space environment. In contrast, the presence of the
window increases the overall mass by a non-negligible quantity. We describe here the radiation and thermal analysis and
their impact on the quality and risks assessment, summarizing the trade-off process with pro and cons on having or
dropping the entrance window in the optical train.
PLATO stands for PLAnetary Transits and Oscillation of stars and is a Medium sized mission selected as M3 by the
European Space Agency as part of the Cosmic Vision program. The strategy behind is to scrutinize a large fraction of the
sky collecting lightcurves of a large number of stars and detecting transits of exo-planets whose apparent orbit allow for
the transit to be visible from the Earth. Furthermore, as the transit is basically able to provide the ratio of the size of the
transiting planet to the host star, the latter is being characterized by asteroseismology, allowing to provide accurate
masses, radii and hence density of a large sample of extra solar bodies. In order to be able to then follow up from the
ground via spectroscopy radial velocity measurements these candidates the search must be confined to rather bright stars.
To comply with the statistical rate of the occurrence of such transits around these kind of stars one needs a telescope with
a moderate aperture of the order of one meter but with a Field of View that is of the order of 50 degrees in diameter. This
is achieved by splitting the optical aperture into a few dozens identical telescopes with partially overlapping Field of
View to build up a mixed ensemble of differently covered area of the sky to comply with various classes of magnitude
stars. The single telescopes are refractive optical systems with an internally located pupil defined by a CaF2 lens, and
comprising an aspheric front lens and a strong field flattener optical element close to the detectors mosaic. In order to
continuously monitor for a few years with the aim to detect planetary transits similar to an hypothetical twin of the Earth,
with the same revolution period, the spacecraft is going to be operated while orbiting around the L2 Lagrangian point of
the Earth-Sun system so that the Earth disk is no longer a constraints potentially interfering with such a wide field
continuous uninterrupted survey.
CHEOPS (CHaracterizing ExOPlanets Satellite) is an ESA Small Mission, planned to be launched in mid-2018 and
whose main goal is the photometric precise characterization of radii of exoplanets orbiting bright stars (V<12) already
known to host planets.
Given the fast-track nature of this mission, we developed a non-flying Demonstration Model, whose optics are flight
representative and whose mechanics provides the same interfaces of the flight model, but is not thermally representative.
In this paper, we describe CHEOPS Demonstration Model handling, integration, tests, alignment and characterization,
emphasizing the verification of the uncertainties in the optical quality measurements introduced by the starlight simulator
and the way the alignment and optical surfaces are measured.
Thermal effects in PLATO are analyzed in terms of uniform temperature variations, longitudinal and lateral temperature gradients. We characterize these effects by evaluating the PSF centroid shifts and the Enclosed Energy variations across the whole FoV. These patterns can then be used to gauge the thermal behavior of each individual telescope in order to improve the local photometric calibration across the PLATO field of view.
The project PLAnetary Transits and Oscillations of stars (PLATO) is one of the selected medium class (M class)
missions in the framework of the ESA Cosmic Vision 2015-2025 program. The main scientific goal of PLATO is the
discovery and study of extrasolar planetary systems by means of planetary transits detection.
According to the current baseline, the scientific payload consists of 34 all refractive telescopes having small aperture
(120mm) and wide field of view (diameter greater than 37 degrees) observing over 0.5-1 micron wavelength band. The
telescopes are mounted on a common optical bench and are divided in four families of eight telescopes with an
overlapping line-of-sight in order to maximize the science return. Remaining two telescopes will be dedicated to support
on-board star-tracking system and will be specialized on two different photometric bands for science purposes.
The performance requirement, adopted as merit function during the analysis, is specified as 90% enclosed energy
contained in a square having size 2 pixels over the whole field of view with a depth of focus of +/-20 micron. Given the
complexity of the system, we have followed a Montecarlo analysis approach for manufacturing and alignment
tolerances. We will describe here the tolerance method and the preliminary results, speculating on the assumed risks and
Global-Multi Conjugate Adaptive Optics (GMCAO) can be a reliable approach for the new generation of Extremely Large Telescopes (ELTs) to address the issue of the sky coverage. It is based on the idea of using the largest possible technical field-of-view, to maximize the chance to find suitable reference stars. To prove that such innovative concept is robust and can be successfully used for studying faint objects, we build mock images of high-z galaxies and analyze them as if they were real and observed with an ELT that benefits of GMCAO. The results we obtained from the analysis of these images claim that this kind of method can be well used for extragalactic deep surveys, a key instrument that next generation telescopes will use to understand the origin and the evolution of galaxies.
In the context of ADONI, the newly constituted laboratory for INAF Adaptive Optics activities, it is foreseen to set-up a facility accessible to the Italian and international AO community, with the purpose of facilitating the testing of critical sub-systems or components (which may be part of instruments under construction), or prototypes of innovative concepts which may require on-sky demonstrations. The 182cm Copernico Telescope located in Asiago (Italy) has been selected to be a suitable place to set-up this public facility, where a common optical bench will be made available at the Coudé focus to host visiting instrumentation. In this paper we describe the opto-mechanical train to the Coudé focal station to be implemented for the laboratory set-up, and we sketch out the foreseen telescope refurbishing activities to implement this multi-purpose testing facility dedicated to AO related projects.
The Pyramid Sensor (PS) is based on the Focault knife-edge test, yielding then, in geometrical approximation, only the sign of the wavefront slope. To provide linear measurements of the wavefront slopes the PS relies on a technique known as modulation, which also plays a central role to improve the linear range of the pyramid WFS, very small in the nonmodulated case. In the main PS using modulation so far, this task is achieved by moving optical components in the WFS, increasing the complexity of the system. An attractive idea to simplify the optical and mechanical design of a pyramid WFS is to work without any dynamic modulation. <p> </p>This concept was only merely described and functionally tested in the framework of MAD, and subsequently, with a holographic diffuser. The latter produce a sort of random distribution of the light coming out from the pupil plane, leading to sort of inefficient modulation, as most of the rays are focused in the central region of the light diffused by such device. The bi-dimensional original grating is, in contrast, producing a well defined deterministic distribution of the light onto a specifically shaped pattern. A crude option has been already discussed as a possibility, and it is here generalized to holographic plates leading to various distribution of lights, including a circle whose diameter would match the required modulation pattern, or more cost effective approaches like the one of a square pattern. These holographic diffusers would exhibit also zero-th and high order patterns and the actual size of the equivalent modulation would be linearly wavelength dependent, leading to colour effects that requires a careful handling in order to properly choose the right amount of equivalent modulation.
In this work we discuss some options for using Unmanned Aerial Vehicles (UAVs) for daylight alignment activities and maintenance of optical telescopes, relating them to a small numbers of parameters, and tracing which could be the schemes, requirements and benefits for employing them both at the stage of erection and maintenance. UAVs can easily reach the auto-collimation points of optical components of the next class of Extremely Large Telescopes. They can be equipped with tools for the measurement of the co-phasing, scattering, and reflectivity of segmented mirrors or environmental parameters like C<sup>2</sup><sub>n</sub> and C<sup>2</sup><sub>T</sub> to characterize the seeing during both the day and the night.