Solar activity and related space weather phenomena can have a potential impact on the space environment and affect critical infrastructures and systems like, for instance, communication networks, power grids, aviation systems. It is therefore of fundamental importance to forecast these events enough in advance (several hours) to put in place mitigation strategies that can reduce the associated risks. The forecasting of solar activity is only possible by monitoring the complex magnetic structures in the Suns atmosphere that can give birth to sudden explosive events. SAMM, the solar activity MOF monitor, is an undergoing project at INAF-OAR in cooperation with a SME industry (DS Group srl - Avalon Instruments) and funded by the Italian Ministry for economic development (MiSE), for the realization of a robotic telescope, based upon magneto-optical filters, for the continuous monitoring of the magnetic field topology and the Doppler velocity of the plasma, at multiple heights in the solar atmosphere. The first channel of SAMM is currently under on-sky tests and system evaluation.
MOONS is a new Multi-Object Optical and Near-infrared Spectrograph selected by ESO as a third generation
instrument for the Very Large Telescope (VLT). The grasp of the large collecting area offered by the VLT (8.2m
diameter), combined with the large multiplex and wavelength coverage (optical to near-IR: 0.8μm - 1.8μm) of MOONS
will provide the European astronomical community with a powerful, unique instrument able to pioneer a wide range of
Galactic, Extragalactic and Cosmological studies and provide crucial follow-up for major facilities such as Gaia,
VISTA, Euclid and LSST. MOONS has the observational power needed to unveil galaxy formation and evolution over
the entire history of the Universe, from stars in our Milky Way, through the redshift desert, and up to the epoch of very
first galaxies and re-ionization of the Universe at redshift z>8-9, just few million years after the Big Bang. On a
timescale of 5 years of observations, MOONS will provide high quality spectra for >3M stars in our Galaxy and the
local group, and for 1-2M galaxies at z>1 (SDSS-like survey), promising to revolutionise our understanding of the
The baseline design consists of ~1000 fibers deployable over a field of view of ~500 square arcmin, the largest patrol
field offered by the Nasmyth focus at the VLT. The total wavelength coverage is 0.8μm-1.8μm and two resolution
modes: medium resolution and high resolution. In the medium resolution mode (R~4,000-6,000) the entire wavelength
range 0.8μm-1.8μm is observed simultaneously, while the high resolution mode covers simultaneously three selected
spectral regions: one around the CaII triplet (at R~8,000) to measure radial velocities, and two regions at R~20,000 one
in the J-band and one in the H-band, for detailed measurements of chemical abundances.
MOONS is a new conceptual design for a Multi-Object Optical and Near-infrared Spectrograph for the Very Large
Telescope (VLT), selected by ESO for a Phase A study. The baseline design consists of ~1000 fibers deployable over a
field of view of ~500 square arcmin, the largest patrol field offered by the Nasmyth focus at the VLT. The total
wavelength coverage is 0.8μm-1.8μm and two resolution modes: medium resolution and high resolution. In the medium
resolution mode (R~4,000-6,000) the entire wavelength range 0.8μm-1.8μm is observed simultaneously, while the high
resolution mode covers simultaneously three selected spectral regions: one around the CaII triplet (at R~8,000) to
measure radial velocities, and two regions at R~20,000 one in the J-band and one in the H-band, for detailed
measurements of chemical abundances.
The grasp of the 8.2m Very Large Telescope (VLT) combined with the large multiplex and wavelength coverage of
MOONS – extending into the near-IR – will provide the observational power necessary to study galaxy formation and
evolution over the entire history of the Universe, from our Milky Way, through the redshift desert and up to the epoch
of re-ionization at z<8-9. At the same time, the high spectral resolution mode will allow astronomers to study chemical
abundances of stars in our Galaxy, in particular in the highly obscured regions of the Bulge, and provide the necessary
follow-up of the Gaia mission. Such characteristics and versatility make MOONS the long-awaited workhorse near-IR
MOS for the VLT, which will perfectly complement optical spectroscopy performed by FLAMES and VIMOS.
MOONS is a new conceptual design for a multi-object spectrograph for the ESO Very Large Telescope (VLT)
which will provide the ESO astronomical community with a powerful, unique instrument able to serve a wide
range of Galactic, Extragalactic and Cosmological studies. The instrument foresees 1000 fibers which can be
positioned on a field of view of 500 square-arcmin. The sky-projected diameter of each fiber is at least 1 arcsec
and the wavelengths coverage extends from 0.8 to 1.8 μm.
This paper presents and discusses the design of the spectrometer, a task which is allocated to the Italian National
Institute of Astrophysics (INAF).
The baseline design consists of two identical cryogenic spectrographs. Each instrument collects the light from
over 500 fibers and feeds, through dichroics, 3 spectrometers covering the "I" (0.79-0.94 μm), "YJ" (0.94-1.35
μm) and "H" (1.45-1.81 μm) bands.
The low resolution mode provides a complete spectrum with a resolving power ranging from R'4,000 in the
YJ-band, to R'6,000 in the H-band and R'8,000 in the I-band. A higher resolution mode with R'20,000 is
also included. It simultaneously covers two selected spectral regions within the J and H bands.
In this paper we work out the optical design of, basically, a limited Field of View off-axis camera. This element is the
ingredient of a much more complex very wide field of view spectrograph and it is intended to avoid technological
difficulties related with huge optics by replicating such element (or family of such elements). The optical design has to
deal with the large off-axis aberration at a point in the Field of View as far from the optical axis as about 0.75 degree.
This requires special tools for treating the convergence of the optical design as, for instance, vignetting on the edges can
be severe because of the strong aberrations at the field lens entrance. Constraints into the optical design are particularly
interesting as well: in fact the overall cross section of the design have to lie within the footprint of the entrance Field of
View in order to allow for an array of such a design to be assembled together and guarantee the space for the allocation
of micro-mechanisms required for movable slits and grisms in each module.
LINC-NIRVANA is the IR Fizeau interferometric imager that will be installed within a couple of years on the Large
Binocular Telescope (LBT) in Arizona. Here we present a particular sub-system, the so-called Patrol Camera (PC),
which has been now completed, along with the results of the laboratory tests. It images (in the range 600-900 nm) the
same 2 arcmin FoV seen by the Medium-High Wavefront Sensor (MHWS), adequately sampled to provide the MHWS
star enlargers with the positions of the FoV stars with an accuracy of 0.1 arcsec. To this aim a diffraction-limited
performance is not required, while a distortion free focal plane is needed to provide a suitable astrometric output. Two
identical systems have been realized, one for each single arm, which corresponds to each single telescope. We give here
the details concerning the optical and mechanical layout, as well as the CCD and the control system. The interfaces (mainly software procedures) with LINC-NIRVANA (L-N) are also presented.
Wide field spectrograph at the largest optical telescopes will be decisive to address the main open questions in modern
astrophysics. The key feature of this instrument is the modular concept: the spectrograph is the combination of about one
thousand identical small cameras, each carrying a few slits and operating at low to moderate spectral resolution, to be
illuminated at the Cassegrain focus of an existing 8m class telescope. The dispersing element to be used in these small
cameras has to satisfy some requirements in term of efficiency, resolution, size, small series production. Moreover the
cameras have to work both in imaging and spectroscopy modes, therefore a GRISM configuration of the dispersing
element is suitable. Based on these considerations, we have focused our attention to Volume Phase Holographic Gratings
(VPHGs) since they show large peak efficiency in the target spectral range (400-800 nm), they can be arranged in a
GRISM configuration reaching relative large resolution. The main constrains concern the available room for the
dispersing element, indeed the camera design is very compact. As a consequence, slanted VPHGs are studied and
optimized in combination with normal and Fresnel prisms.
The concept of segmenting the focal plane of an existing 8m class telescope in order to fill it with an array of several fast
cameras has been developed further and in this work the status of an engineering program aimed to produce a design
qualified for the construction, and to assess its cost estimates is presented. The original concept of just having simple
cameras with all identical optical components other than a pupil plane corrector to remove the fixed aberrations at the
off-axis field of a telescope has been extended to introduce a spectroscopic capability and to assess a trade-off between a
very large number (of the order of thousand) of cameras with a small single Field of View with a smaller number of
cameras able to compensate the aberration on a much larger Field of View with a combination of different optical
elements and different ways to mount and align them.
The scientific target of a few thousands multi-slit spectra over a Field of View of a few square degrees, combined with
the ambition to mount this on an existing 8m class telescope makes the scientific rationale of such an instrument a very
interesting one. In the paper we describe the different options for a possible optical design, the trade off between
variations on the theme of the large segmentation and we describe briefly the way this kind of instrument can handle a
multi-slit configuration. Finally, the feasibility of the components and a brief description of how the cost analysis is
being performed are given. Perspectives on the construction of this spectrograph are given as well.
The VLTI Spectro Imager (VSI) was proposed as a second-generation instrument of the Very Large Telescope Interferometer
providing the ESO community with spectrally-resolved, near-infrared images at angular resolutions
down to 1.1 milliarcsecond and spectral resolutions up to R = 12000. Targets as faint as K = 13 will be imaged
without requiring a brighter nearby reference object; fainter targets can be accessed if a suitable reference is
available. The unique combination of high-dynamic-range imaging at high angular resolution and high spectral
resolution enables a scientific program which serves a broad user community and at the same time provides the
opportunity for breakthroughs in many areas of astrophysics. The high level specifications of the instrument are
derived from a detailed science case based on the capability to obtain, for the first time, milliarcsecond-resolution
images of a wide range of targets including: probing the initial conditions for planet formation in the AU-scale
environments of young stars; imaging convective cells and other phenomena on the surfaces of stars; mapping
the chemical and physical environments of evolved stars, stellar remnants, and stellar winds; and disentangling the central regions of active galactic nuclei and supermassive black holes. VSI will provide these new capabilities
using technologies which have been extensively tested in the past and VSI requires little in terms of new
infrastructure on the VLTI. At the same time, VSI will be able to make maximum use of new infrastructure as it
becomes available; for example, by combining 4, 6 and eventually 8 telescopes, enabling rapid imaging through
the measurement of up to 28 visibilities in every wavelength channel within a few minutes. The current studies
are focused on a 4-telescope version with an upgrade to a 6-telescope one. The instrument contains its own
fringe tracker and tip-tilt control in order to reduce the constraints on the VLTI infrastructure and maximize
the scientific return.
We present the optical and cryo-mechanical solutions for the Spectrograph of VSI (VLTI Spectro-Imager), the second
generation near-infrared (J, H and K bands) interferometric instrument for the VLTI. The peculiarity of this spectrograph
is represented by the Integrated Optics (IO) beam-combiner, a small and delicate component which is located inside the
cryostat and makes VSI capable to coherently combine 4, 6 or even 8 telescopes. The optics have been specifically
designed to match the IO combiner output with the IR detector still preserving the needed spatial and spectral sampling,
as well as the required fringe spacing. A compact device that allows us to interchange spectral resolutions (from R=200
to R=12000), is also presented.
Since the very beginning of 2008, the Large Binocular Telescope (LBT) is officially equipped with it's first binocular
instrument ready for science observations: the Large Binocular Camera (LBC). This is a double CCD imager, installed at
the prime focus stations of the two 8.4m telescopes of LBT, able to obtain deep and wide field images in the whole
optical spectrum from UV to NIR wavelengths.
We present here the overall architecture of the instrument, a brief hardware review of the two imagers and notes how
observations are carried on. At the end we report preliminary results on the performances of the instrument along with
some images obtained during the first months of observations in binocular mode.
LINC-NIRVANA is the IR Fizeau interferometric imager of the Large Binocular Telescope (LBT) in Arizona.
Here we describe in particular the design, realization and preliminary tests of the so-called Patrol Camera. It
can image (in the range 600-900 nm) the same 2 arcmin FoV seen by the Medium- High-Wavefront Sensor
(MHWS), adequately sampled to provide the MHWS star enlargers with the positions of the FoV stars with
an accuracy of 0.1 arcsec. To this aim a diffraction-limited performance is not required, while a distortion free
focal plane is needed to provide a suitable astrometric output. Two identical systems will be realized, one for
each single arm, which corresponds to each single telescope. We give here the details concerning the optical
and mechanical design, as well as the CCD and the control system. The interfaces with LINC-NIRVANA are
also presented both in terms of matching the carbon fiber optical bench and developing of suitable software
procedures. Since the major components have been already gathered, the laboratory tests and the integration
are currently in progress.
It is generally believed that very fast cameras imaging large Fields of View translate into huge optomechanics
and mosaics of very large contiguous CCDs. It has already been suggested that seeing limited imaging cameras
for telescopes whose diameters are larger than 20m are considered virtually impossible for a reasonable cost.
It has also been suggested that using existing technology and at a moderate price, one can build a Smart Fast
Camera, a device that placed on aberrated Field of View, including those of slow focal ratios, is able to provide
imaging at an equivalent focal ratio as low as F/1, with a size that is identical to the large focal ratio focal plane
size. The design allows for easy correction of aberrations over the Field of View. It has low weight and size
with respect to any focal reducer or prime focus station of the same performance. It can be applied to existing
8m-class telescopes to provide a wide field fast focal plane or to achieve seeing-limited imaging on Extremely
Large Telescopes. As it offers inherently fast read-out in a massive parallel mode, the SFC can be used as a
pupil or focal plane camera for pupil-plane or Shack-Hartmann wavefront sensing for 30-100m class telescopes.
Basing upon Smart Fast Camera concept, we present a study turned to explain the pliability of this instrument
for different existing telescopes.
The Large Binocular Telescope is currently equipped with a couple of wide field Prime Focus. The two cameras are optimized for, respectively, the blue and the red portion of the visible spectrum. The history of this project is here sketched up and the current status is shown. The Blue channel is currently working onboard the telescope and provided what has been named the first-light of the telescope in single eye configuration.
We describe the procedures adopted to realize the fiber unit for feeding the near IR multi-object spectrometer GOHSS. Since a scarce literature is available on this subject, all the steps of the fabrication processes are explained and documented through a detailed illustrative material: in particular the polishing methods of the fiber ends are addressed along with the criteria for evaluating the achieved results; the preparation and application of the ferrules; the matching with the input micro-lens; finally, the laboratory tests to measure the focal ratio degradation of each fiber are presented aiming also to certify the quality of the realized device.
The Prime Focus for the Large Binocular Telescope are a couple of Prime Focus stations each equipped with four 4kx2k CCDs and a six lenses corrector with an aspheric surface and the first lens as large as roughly 800mm in diameter. These cameras will cover almost half degree of Field of View on 8m-class telescopes with unprecedented velocity of F/1.4. The two units are optimized for the Red and Blue portions of the visible wavelength and additionally an extension to J and H bands is foreseen. An overview of the project, including the optomechanics, the cryogenics, the electronics, and the software is given along with a preliminary account of lessons learned and on how much the second unit, the Red one, the schedule of which is shifted with respect to the Blue one by several months, will take advantage from the experience gained in the Blue unit assembly and integration.
The Large Binocular Camera (LBC) is the double optical imager whose blue channel is going to start the commissioning phase at the Large Binocular Telescope (2x8.4 m). We present the updated characteristics of the CCD camera and its characterization performed in the laboratory of the Rome Observatory and in the integration room of the Arcetri Observatory.
The LBT double prime focus camera (LBC) is composed of twin CCD mosaic imagers. The instrument is designed to match the double channel structure of the LBT telescope and to exploit parallel observing mode by optimizing one camera at blue and the other at red side of the visible spectrum. Because of these facts, the LBC activity will likely consist of simultaneous multi-wavelength observation of specific targets, with both channels working at the same time to acquire and download images at different rates. The LBC Control Software is responsible for coordinating these activities by managing scientific sensors and all the ancillary devices such as rotators, filter wheels, optical correctors focusing, house-keeping information, tracking and Active Optics wavefront sensors. The result is obtained using four dedicated PCs to control the four CCD controllers and one dual processor PC to manage all the other aspects including instrument operator interface. The general architecture of the LBC Control Software is described as well as solutions and details about its implementation.
The Large Binocular Camera (LBC) is the double optical imager that will be installed at the prime foci of the Large Binocular Telescope (2x8.4 m). Four Italian observatories are cooperating in this project: Rome (CCD Camera), Arcetri-Padua (Optical Corrector) and Trieste (Software). LBC is composed by two separated large field (27 arcmin FOV) cameras, one optimized for the UBV bands and the second for the VRIZ bands. An optical corrector balances the aberrations induced by the fast (F#=1.14) parabolic primary mirror of LBT, assuring that the 80% of the PSF encircled energy falls inside one pixel for more of the 90% of the field. Each corrector uses six lenses with the first having a diameter of 80cm and the third with an aspherical surface. Two filter wheels allow the use of 8 filters. The two channels have similar optical designs satisfying the same requirements, but differ in the lens glasses: fused silica for the "blue" arm and BK7 for the "red" one. The two focal plane cameras use an array of four 4290 chips (4.5x2 K) provided
by Marconi optimized for the maximum quantum efficiency (85%) in each channel. The sampling is 0.23 arcseconds/pixel. The arrays are cooled by LN2 cryostats assuring 24 hours of operation. Here we present a description of the project and its current status including a report about the Blue camera and its laboratory tests. This instrument is planned to be the first light instrument of LBT.
We describe the current status and technical aspects of the GOHSS (Galileo OH Subtracted Spectrograph) project. Here we point out the most critical items and how we have implemented innovative technical solutions to fulfill the compelling requirements imposed by both the optical tolerances and the demands of a high sensitivity. In particular we examine the camera lens mechanics realized in ultra low expansion quartz; the refrigerator system; the IR array mount realized in an unconventional way; the effort put in procuring optical devices with quite large efficiencies. We are also developing the data reduction package along with the instrument simulator: the optimized procedures and the results on the visibility function of galaxies are given as well. Currently the instrument is in the integration phase at the laboratories of the Astronomical Observatory of Rome and the commissioning phase at the telescope is expected to start at the beginning of year 2003.
The Large Binocular Camera (LBC) is a double prime focus station to be mounted on the Large Binocular Telescope (LBT). The two channels, called Blue and Red, are optimized for the UB and VRIZ bands respectively and are characterized by two optical correctors with very fast focal ratio (F/1.45) and challenging optical and mechanical specifications. We present here a review of the optical and mechanical design of both the optical correctors and report on the current status of the manufacturing and integration.
In this paper we present the new optical camera ROSI mounted at the 60/90/180 Schmidt telescope of the Campo Imperatore Station. We have developed a new LN<SUB>2</SUB> compact cryostat designed to be mounted directly at the internal focus of the telescope and optimized to obtain a very long duration of the cryogenic liquid. The instrument is based on a 2K by 2K thinned EEV cooled down to 180K and despite of the reduced capacity of the vessel the overall holding time of LN<SUB>2</SUB> is greater than 10 hours, providing a long working cycle. The CCD is controlled by a modified version of the Astrocam DUO provided by LSR that offers both a high readout speed and a low noise. ROSI has been equipped with the same high transmission filter set use din SUSI2 provided by CETEV. The computer design of the entire instrument allows a negligible obscure of the light path, comparable to the traditional one of the Schmidt telescopes equipped with photographic plates.
We present the main characteristics and astronomical results of SWIRCAM, a NIR imager-spectrometer mainly devoted to the search for extragalactic Supernovae, in the frame of the SWIRT project, a joint scientific collaboration among the Astronomical Observatories of Rome, Teramo and Pulkovo. The camera is currently at the focal plane of the AZT-24 1.1 m telescope at the Observing Station of Campo Imperatore, operated by the Astronomical Observatory of Rome. SWIRCAM saw its first light during December 1998 and it is currently employed for both the SWIRT operative phase and other institutional projects.
We describe the current status of the technical aspects of the GOHSS project. It consists of a fiber-fed NIR spectrograph for faint objects. It will be a second-light instrument for the Nasmyth focus of the 3.5m Galileo telescope located on La Palma. GOHSS is an innovative instrument which accomplishes OH night-sky subtraction, differently from the hardware solution used by other devices; it provides a multiechelle design with software OH subtraction capable of yielding about 25 spectra in the z,J and H bands at an effective spectral resolution of about 4000, which is necessary to strongly reduce the impact of atmospheric OH lines. The GOHSS design is completed and the operative phase is already started through the procurement of the most important components. We have also started to develop the data reduction package for the instrument and the first result of the 1D approach as presented.
The large Binocular Telescope is currently in the pre- erection phase. The instrument has been already funded and its first-light is expected shortly after that of the LBT. Given the peculiarity of the telescope optics we designed tow prime focus cameras with two five-lens refractive correctors, optimized in the blue-side and red-side of the visible spectrum respectively. This independent coating. Detectors also reflect this choice, being optimized separately. We present the most relevant features of the instrument, the optical design as well as the structural and mechanical layout. Each of the two Prime Focus cameras gather light form a very fast, F/1.14 parabolic primary mirror. The field is corrected over roughly half a degree in size, allowing optical performances in terms of 80 percent of Encircled Energy in better than approximately 0.3 inch. Focal length is slightly increased in order to provide a better sampling using 13.5 micrometers pixel size chips. The CCD array is made up with 4 EEV 42-90 chips, per channel, to obtain an equivalent 6000 by 6000 pixels optimizing the AR coating to the U,B,V and V,R,I,Z bands respectively. The array will be read out in 10 seconds using a 1Meegapixel/second controller with four video channels. The cryostat will use a state of the art dewar to reach an holding time of several days using a limited amount of liquid nitrogen. The whole mechanical design has bene modeled using Finite Elements analysis in order to check for mechanical flexures of the mount tube and of the optical components by themselves. A brief overview of the informative facilities to be provided with the instrument and of a few science case studies that can be attacked by this instrument are also given.
Telescope, dome and camera controls can be seen as independent systems managed by an ad hoc software. We have used both hardware intelligence and a distributed PC based software to produce a system performing interactive and automatic observations. An integrated and automated data reduction pipeline allows most almost real-time image processing and WEB searchable archiving.