The ASTRI mini-array, composed of nine small-size dual mirror (SST-2M) telescopes, has been proposed to be installed at the southern site of the Cherenkov Telescope Array (CTA), as a set of preproduction units of the CTA observatory. The ASTRI mini-array is a collaborative and international eﬀort carried out by Italy, Brazil and South Africa and led by the Italian National Institute of Astrophysics, INAF. We present the main features of the current implementation of the Mini-Array Software System (MASS) now in use for the activities of the ASTRI SST-2M telescope prototype located at the INAF observing station on Mt. Etna, Italy and the characteristics that make it a prototype for the CTA control software system. CTA Data Management (CTADATA) and CTA Array Control and Data Acquisition (CTA-ACTL) requirements and guidelines as well as the ASTRI use cases were considered in the MASS design, most of its features are derived from the Atacama Large Millimeter/sub-millimeter Array Control software. The MASS will provide a set of tools to manage all onsite operations of the ASTRI mini-array in order to perform the observations speciﬁed in the short term schedule (including monitoring and controlling all the hardware components of each telescope and calibration device), to analyze the acquired data online and to store/retrieve all the data products to/from the onsite repository.
Aqueye+ is a new ultrafast optical single photon counter, based on single photon avalanche photodiodes (SPAD) and a 4- fold split-pupil concept. It is a completely revisited version of its predecessor, Aqueye, successfully mounted at the 182 cm Copernicus telescope in Asiago. Here we will present the new technological features implemented on Aqueye+, namely a state of the art timing system, a dedicated and optimized optical train, a high sensitivity and high frame rate field camera and remote control, which will give Aqueye plus much superior performances with respect to its predecessor, unparalleled by any other existing fast photometer. The instrument will host also an optical vorticity module to achieve high performance astronomical coronography and a real time acquisition of atmospheric seeing unit. The present paper describes the instrument and its first performances.
The control software of the Large Binocular Telescope's (LBT) double prime focus cameras (LBC) has been in use for a decade: the software passed acceptance testing in April 2004 and is currently in routine use for science. LBC was the first light instrument of the telescope. Over the last decade of use, the control software has changed as operations with the telescope have evolved. The major updates to the LBC control software since 2004 are described, including details for the upgrade to a single control computer from the current five computer architecture.
ASTRI is the flagship project of INAF (Italian National Institute for Astrophysics) mainly devoted to the
development of Cherenkov small-size dual-mirror telescopes (SST-2M) in the framework of the international
Cherenkov Telescope Array (CTA) Project. ASTRI SST-2M is an end-to-end prototype including scientific and
technical operations as well as the related data analysis and archiving activities. We present here the ASTRI data
handling and archiving system: it is responsible for both the on-site and off-site data processing and archiving.
All the scientific, calibration, and engineering ASTRI data will be stored and organized in dedicated archives
aimed to provide access to both the monitoring and data analysis systems.
ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana) is a Flagship Project financed by the Italian Ministry of Education, University and Research, and led by INAF, the Italian National Institute of Astrophysics. The main goals of the ASTRI project are the realization of an end-to-end prototype of a Small Size Telescope (SST) for the Cherenkov Telescope Array (CTA) in a dual- mirror configuration (SST-2M) and, subsequently, of a mini-array comprising seven SST-2M telescopes. The mini-array will be placed at the final CTA Southern Site, which will be part of the CTA seed array, around which the whole CTA observatory will be developed. The Mini-Array Software System (MASS) will provide a comprehensive set of tools to prepare an observing proposal, to perform the observations specified therein (monitoring and controlling all the hardware components of each telescope), to analyze the acquired data online and to store/retrieve all the data products to/from the archive. Here we present the main features of the MASS and its first version, to be tested on the ASTRI SST-2M prototype that will be installed at the INAF observing station located at Serra La Nave on Mount Etna in Sicily.
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.
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 early future of astronomy will be dominated by Extremely Large Telescopes where the focal
lengths will be of the order of several hundred meters. This yields focal plane sizes of roughly one
square meter to obtain a field of view of about 5 x 5 arcmin. When operated in seeing limited mode this
field is correctly sampled with 1x1mm pixels. Such a sampling can be achieved using a peculiar array
of tiny CMOS active photodiodes illuminated through microlenses or lightpipes. If the photodiode is
small enough and utilizes the actual pixel technology, its dark current can be kept well below the sky
background photocurrent, thus avoiding the use of cumbersome cryogenics systems. An active smart
electronics will manage each pixel up to the A/D conversion and data transfer. This modular block is
the Pixel-One. A 30x30 mm tile filled with 1000 Pixel-Ones could be the basic unit to mosaic very
large focal planes. By inserting dispersion elements inside the optical path of the lenslet array one
could also produce a low dispersed spectrum of each focal plane sub-aperture and, by using an array of
few smart photodiodes, also get multi-wavelength information in the optical band for each equivalent
focal plane pixel. An application to the E-ELT is proposed.
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.
Iqueye is a single photon counting very high speed photometer built for the ESO 3.5m New Technology Telescope
(NTT) in La Silla (Chile) as prototype of a 'quantum' photometer for the 42m European Extremely Large Telescope (E-ELT).
The optics of Iqueye splits the telescope pupil into four portions, each feeding a Single Photon Avalanche Diode
(SPAD) operated in Geiger mode. The SPADs sensitive area has a diameter of 100 μm, with a quantum efficiency better
than 55% at 500 nm, and a dark count less than 50 Hz. The quenching circuit and temperature control are integrated in
each module. A time-to-digital converter (TDC) board, controlled by a rubidium oscillator plus a GPS receiver, time tags
the pulses from the 4 channels. The individual times are stored in a 2 TeraByte memory. Iqueye can run continuously for
hours, handling count rates up to 8 MHz, with a final absolute accuracy of each time tag better that 0.5 ns. A first very
successful run was performed in Jan 2009; both very faint and very bright stars were observed, demonstrating the high
photometric quality of the instrument. The first run allowed also to identify some opto-mechanical improvements, which
have been implemented for a second run performed in Dec 2009. The present paper will describe the first version, the
improvements implemented in the second one, and some of the obtained astronomical results.
Almost all astronomical instruments detect and analyze the first order spatial and/or temporal coherence properties
of the photon stream coming from celestial sources. Additional information might be hidden in the second
and higher order coherence terms, as shown long ago by Hanbury-Brown and Twiss with the Narrabri Intensity
Interferometer. The future Extremely Large Telescopes and in particular the 42 m telescope of the European
Southern Observatory (ESO) could provide the high photon flux needed to extract this additional information.
To put these expectations (which we had already developed at the conceptual level in the QuantEYE study for the
100 m OverWhelmingly Large Telescope to experimental test in the real astronomical environment, we realized
a small prototype (Aqueye) for the Asiago 182 cm telescope. This instrument is the fastest photon counting
photometer ever built. It has 4 parallel channels operating simultaneously, feeding 4 Single Photon-Avalanche
Diodes (SPADs), with the ability to push the time tagging capabilities below the nano-second region for hours
of continuous operation. Aqueye has been extensively used to acquire photons from a variety of variable stars,
in particular from the pulsar in the Crab Nebula. Following this successful realization, a larger version, named
Iqueye, has been built for the 3.5 m New Technology Telescope (NTT) of ESO. Iqueye follows the same optical
solution of dividing the telescope pupil in 4 sub-pupils, imaged on new generation SPADs having useful diameters
of 100 micrometers, time jitter less than 50 picoseconds and dark-count noise less than 50 counts/second. The
spectral efficiency of the system peaks in the visible region of the spectrum. Iqueye operated very successfully at
the NTT in January 2009. The present paper describes the main features of the two photometers and present
some of the astronomical results already obtained.
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.
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.
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 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.
AQuA (Automatic QUick Analysis) is a software designed to manage data
reduction and prompt detection of near infra-red (NIR) afterglows
of GRB triggered by the dedicated instruments onboard satellites and observed with the robotic telescope REM. NIR observations of GRBs early afterglow are of crucial importance for GRBs science, revealing even optical obscured or high redshift events. The core of the pipeline is an algorithm for automatic transient detection, based on a decision tree that is continuously upgraded through a Bayesian estimator (DecOAR). It assigns to every transient candidate different reliability coefficients and delivers an alert when a transient is found above the reliability threshold.
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.
AQUA (Automated QUick Analysis) is the fast reduction pipeline of the Near Infra-Red (NIR) images obtained by the REM telescope. REM (Rapid Eye Mount) is a robotic NIR/Optical 60cm telescope for fast detection of early afterglow of Gamma Ray Bursts (GRB). NIR observations of GRBs early afterglow are of crucial importance for GRBs science, revealing even optical obscured or high redshift events. On the technical side, they pose a series of problems: luminous background, bright sources (as the counterparts should be observed few seconds after the satellite trigger) and fast detection force high rate images acquisition. Even if the observational strategy will change during the same event observation depending on the counterpart characteristics, we will start with 1 second exposures at the fastest possible rate. The main guideline in the AQUA pipeline development is to allow such a data rate along all the night with nearly real-time results delivery. AQUA will start from the raw images and will deliver an alert with coordinates, photometry and colors to larger telescopes to allow prompt spectroscopic and polarimetric observations. Very fast processing for the raw 512×512 32bit images and variable sources detection with both sources catalogs and images comparison have been implemented to obtain a processing speed of at least 1 image/sec. AQUA is based on ANSI-C code optimized to run on a dual Athlon Linux PC with careful MMX and SSE instructions utilization.
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.
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 LN2 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 LN2 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.
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.