Author name code: cavallini
ADS astronomy entries on 2022-09-14
author:"Cavallini, Fabio" 
------------------------------------------------------------------------  

Title: A Prototype of a Large Tunable Fabry-Pérot Interferometer
    for Solar Spectroscopy
Authors: Greco, V.; Sordini, A.; Cauzzi, G.; Cavallini, F.; Del
   Vecchio, C.; Giovannelli, L.; Berrilli, F.; Del Moro, D.; Reardon,
   K.; Pietraszewski, K. A. R. B.
Bibcode: 2022PASP..134a5007G
Altcode: 2021arXiv211202224G
  Large Fabry-Pérot Interferometers (FPIs) are used in a variety of
  astronomical instrumentation, including spectro-polarimeters for 4 m
  class solar telescopes. In this work we comprehensively characterize
  the cavity of a prototype 150 mm FPI, sporting a novel, fully symmetric
  design. Of particular interest, we define a new method to properly
  assess the gravity effects on the interferometer's cavity when the
  system is used in either the vertical or horizontal configuration,
  both typical of solar observations. We show that the symmetric design
  very effectively limits the combined effects of pre-load and gravity
  forces to only a few nm over a 120 mm diameter illuminated surface,
  with gravity contributing ~2 nm peak-to-valley (~0.3 nm rms) in either
  configuration. We confirm a variation of the tilt between the plates
  of the interferometer during the spectral scan, which can be mitigated
  with appropriate corrections to the spacing commands. Finally, we show
  that the dynamical response of the new system fully satisfies typical
  operational scenarios. We conclude that large, fully symmetric FPIs
  can be safely used within solar instrumentation in both, horizontal
  and vertical position, with the latter better suited to limiting the
  overall volume occupied by such an instrument.

Title: New technique to measure the cavity defects of Fabry-Perot
    interferometers
Authors: Greco, V.; Sordini, A.; Cauzzi, G.; Reardon, K.; Cavallini, F.
Bibcode: 2019A&A...626A..43G
Altcode: 2019arXiv190501393G
  Context. Several astronomical instruments, for both nighttime and
  solar use, rely on tunable Fabry-Perot interferometers (FPIs). Knowing
  the exact shape of the etalons' cavity is crucial for assessing the
  overall instrumental transmission profile and its possible variations
  during the tuning process. <BR /> Aims: We aim to define and test
  a technique to accurately measure the cavity defects of air-spaced
  FPIs, including distortions due to the spectral tuning process that
  are typical of astronomical observations. We further aim to develop a
  correction technique to maintain the shape of the cavity as constant as
  possible during the spectral scan. These are necessary steps to optimize
  the spectral transmission profile of a two-dimensional spectrograph
  (polarimeter) using one or more FPIs in series, and to ensure that
  the spectral transmission profile remains constant during typical
  observing conditions. <BR /> Methods: We devised a generalization of the
  techniques developed for the so-called phase-shifting interferometry to
  the case of FPI. This measuring technique is applicable to any given FPI
  that can be tuned via changing the cavity spacing (z-axis), and can be
  used for any etalon regardless of the coating' reflectivity. The major
  strength of our method is the ability to fully characterize the cavity
  during a spectral scan, allowing for the determination of scan-dependent
  modifications of the plates. We have applied the measuring technique to
  three 50 mm diameter interferometers, with cavity gaps ranging between
  600 μm and 3 mm, coated for use in the visible range. <BR /> Results:
  The technique developed in this paper allows us to accurately and
  reliably measure the cavity defects of air-spaced FPIs, and of their
  evolution during the entire spectral scan. Our main, and unexpected,
  result is that the relative tilt between the two FPI plates varies
  significantly during the spectral scan, and can dominate the cavity
  defects; in particular, we observe that the tilt component at the
  extremes of the scan is sensibly larger than that at the center of
  the scan. Exploiting the capability of the electronic controllers to
  set the reference plane at any given spectral step, we then develop
  a correction technique that allows the minimization of the tilt
  during a complete spectral scan. The correction remains highly stable
  over long periods, well beyond the typical duration of astronomical
  observations. <P />Movies attached to Figs. 6 and 13 are available at <A
  href="https://www.aanda.org/10.1051/0004-6361/201935302/olm">https://www.aanda.org</A>

Title: ADAHELI: exploring the fast, dynamic Sun in the x-ray, optical,
    and near-infrared
Authors: Berrilli, Francesco; Soffitta, Paolo; Velli, Marco; Sabatini,
   Paolo; Bigazzi, Alberto; Bellazzini, Ronaldo; Bellot Rubio, Luis
   Ramon; Brez, Alessandro; Carbone, Vincenzo; Cauzzi, Gianna; Cavallini,
   Fabio; Consolini, Giuseppe; Curti, Fabio; Del Moro, Dario; Di Giorgio,
   Anna Maria; Ermolli, Ilaria; Fabiani, Sergio; Faurobert, Marianne;
   Feller, Alex; Galsgaard, Klaus; Gburek, Szymon; Giannattasio, Fabio;
   Giovannelli, Luca; Hirzberger, Johann; Jefferies, Stuart M.; Madjarska,
   Maria S.; Manni, Fabio; Mazzoni, Alessandro; Muleri, Fabio; Penza,
   Valentina; Peres, Giovanni; Piazzesi, Roberto; Pieralli, Francesca;
   Pietropaolo, Ermanno; Martinez Pillet, Valentin; Pinchera, Michele;
   Reale, Fabio; Romano, Paolo; Romoli, Andrea; Romoli, Marco; Rubini,
   Alda; Rudawy, Pawel; Sandri, Paolo; Scardigli, Stefano; Spandre,
   Gloria; Solanki, Sami K.; Stangalini, Marco; Vecchio, Antonio;
   Zuccarello, Francesca
Bibcode: 2015JATIS...1d4006B
Altcode:
  Advanced Astronomy for Heliophysics Plus (ADAHELI) is a project concept
  for a small solar and space weather mission with a budget compatible
  with an European Space Agency (ESA) S-class mission, including launch,
  and a fast development cycle. ADAHELI was submitted to the European
  Space Agency by a European-wide consortium of solar physics research
  institutes in response to the "Call for a small mission opportunity
  for a launch in 2017," of March 9, 2012. The ADAHELI project builds
  on the heritage of the former ADAHELI mission, which had successfully
  completed its phase-A study under the Italian Space Agency 2007 Small
  Mission Programme, thus proving the soundness and feasibility of
  its innovative low-budget design. ADAHELI is a solar space mission
  with two main instruments: ISODY: an imager, based on Fabry-Pérot
  interferometers, whose design is optimized to the acquisition of
  highest cadence, long-duration, multiline spectropolarimetric images
  in the visible/near-infrared region of the solar spectrum. XSPO: an
  x-ray polarimeter for solar flares in x-rays with energies in the 15
  to 35 keV range. ADAHELI is capable of performing observations that
  cannot be addressed by other currently planned solar space missions,
  due to their limited telemetry, or by ground-based facilities, due to
  the problematic effect of the terrestrial atmosphere.

Title: Design of the optics for an imaging classic mount multi-etalon
    spectro-polarimeter for the next generation of ground-based solar
    telescopes
Authors: Greco, V.; Cavallini, F.
Bibcode: 2011SPIE.8172E..19G
Altcode: 2011SPIE.8172E..31G
  In designing the optics of an imaging classic mount multi-étalon
  spectro-polarimeter as a post-focus instrument for the next generation
  of ground-based solar telescopes (Advanced Technology Solar Telescope,
  European Solar Telescope), many constraints must be considered. The
  large entrance pupil diameter of the telescope (4 m), the demanded large
  field of view (&gt;= 90 arcsec), high spectral resolving power (&gt;=
  200000), and limited field-dependent blue-shift of the instrumental
  profile (&lt;= 3 FWHM) require Fabry-Pérot interferometers of large
  diameter (&gt;= 200 mm), lighted by highly collimated beams. This
  implies large optical elements and long optical paths. Moreover, to
  use interference pre-filters, placed between the interferometers to
  reduce the inter-reflections in axial-mount, with a relatively small
  diameter (&lt;= 70 mm), a "pupil adapter" should be included, with a
  further increase of the optical path length. Although a multi-étalon
  spectro-polarimeter works in quasi-monochromatic light, the Fraunhofer
  lines of interest cover a wide range of wavelengths (850 nm - 1650
  nm), demanding a good chromatic aberration control. Finally, a low
  instrumental polarization (&lt;= 0.5 %) is required to allow a high
  polarimetric precision. In this paper a diffraction limited optical
  solution is described, fulfilling all the above requirements in a
  relative small volume.

Title: The Fabry-Perot interferometer prototype for the ADAHELI
    solar small mission
Authors: Berrilli, Francesco; Cocciolo, Martina; Giovannelli, Luca; Del
   Moro, Dario; Giannattasio, Fabio; Piazzesi, Roberto; Stangalini, Marco;
   Egidi, Alberto; Cavallini, Fabio; Greco, Vincenzo; Selci, Stefano
Bibcode: 2011SPIE.8148E..07B
Altcode: 2011SPIE.8148E...6B
  ADAHELI ADvanced Astronomy for HELIophysics is a solar satellite
  designed to investigate the fast dynamics of the solar photosphere and
  chromosphere performing visible and NIR broad-band and monochromatic
  observations of selected atomic lines. ADAHELI is an Italian Space
  Agency (ASI) project, approved for a feasibility study within the
  ASI Small Missions call. ISODY Interferometer for SOlar DYnamics is
  a Gregorian telescope and its focal plane suite (FPS). The FPS is
  composed of a high-resolution fast acquisition system, based upon a
  tandem of Fabry-Pérot interferometers operating in the visible and
  NIR regions on selected solar atmospheric lines, a broad band channel,
  and a correlation tracker used as image stabilization system. In this
  contribution we describe the Fabry-Pérot étalon prototype, based
  on the capacitance-stabilised concept, realized in our laboratory
  to perform preliminary mechanical and optical tests with a view to a
  future Fabry-Pérot étalon prototype for space application.

Title: The telescope and the double Fabry-Pérot interferometer for
    the ADAHELI solar space mission
Authors: Greco, V.; Cavallini, F.; Berrilli, F.
Bibcode: 2010SPIE.7731E..42G
Altcode: 2010SPIE.7731E.131G
  ADvanced Astronomy for HELIophysics (ADAHELI) is a Small Mission to
  study the structure and fast dynamics of the low solar atmosphere,
  performing Visible-NIR monochromatic and broad-band observations. The
  mission will achieve millimeter full disk observations as well. The
  ADAHELI Team has succesfully completed, in December 2008, the Phase
  A study awarded by the Italian Space Agency (ASI). The Interferometer
  for SOlar Dynamics (ISODY), on board the ADAHELI satellite, comprises
  a Gregorian telescope and its focal plane suite. The advanced design
  focal plane suite uses fast CMOS cameras for investigating photospheric
  and chromospheric fast dynamics and structure. ISODY is equipped
  with a pioneering focal plane suite composed of a spectral channel,
  based upon a tandem of Fabry-Perot interferometers operating in the
  visible-NIR spectral region, a broad band channel for high resolution
  imaging, and a correlation tracker used as an image stabilization
  system. ADAHELI's mission profile has been tailored to limit the
  spacecraft's radial velocity in the Sunward direction, to not exceed
  +/-4 km/s, during 95% of the yearly orbit, to allow a continuous use
  of the on-board interferometer.

Title: Imaging performance of multi-etalon bidimensional spectrometers
Authors: Righini, A.; Cavallini, F.; Reardon, K. P.
Bibcode: 2010A&A...515A..85R
Altcode:
  <BR /> Aims: In recent years, several new solar and nighttime
  panoramic spectrometers based on Fabry-Perot interferometers have
  been successfully developed. In this paper we evaluate the imaging
  performance of the two types of mountings that have been adopted,
  telecentric and classic, in particular trying to understand which one
  might be more suitable for future large-aperture solar telescopes. <BR
  /> Methods: Numerical code was written to simulate the behavior of such
  spectrometers, on the basis of the theory of Fourier optics. This code
  was used to simulate different instrument configurations and was tested
  on previous results obtained either analytically or numerically by
  other authors. <BR /> Results: Calculations of the system MTF and Strehl
  ratios show that both mountings may perform very close to theoretical
  expectations. However, gap irregularities in the interferometers
  may alter the optical quality of the monochromatic images. In the
  case of the classical mounting in a collimated beam, it is possible
  to partially compensate for the resulting errors in the wavefront
  emerging from the interferometers with a suitable phase plate. We also
  performed an observational test of the optical quality delivered by
  the IBIS interferometer installed at the Dunn Solar Telescope of the
  National Solar Observatory, with the results substantially confirming
  the calculations. <BR /> Conclusions: It follows from our results
  that both mountings may be efficiently used for solar bidimensional
  spectroscopy. The final choice depends on the tradeoff between factors
  such as image quality, field of view, and acceptable wavelength shift.

Title: The ADAHELI solar mission: Investigating the structure of
    Sun's lower atmosphere
Authors: Berrilli, F.; Bigazzi, A.; Roselli, L.; Sabatini, P.; Velli,
   M.; Alimenti, F.; Cavallini, F.; Greco, V.; Moretti, P. F.; Orsini,
   S.; Romoli, M.; White, S. M.; ADAHELI Team; Ascani, L.; Carbone, V.;
   Curti, F.; Consolini, G.; Di Mauro, M. P.; Del Moro, D.; Egidi, A.;
   Ermolli, I.; Giordano, S.; Pastena, M.; Pulcino, V.; Pietropaolo, E.;
   Romano, P.; Ventura, P.; Cauzzi, G.; Valdettaro, L.; Zuccarello, F.;
   ADAHELI Team
Bibcode: 2010AdSpR..45.1191B
Altcode: 2010AdSpR..45.1191A
  ADAHELI (ADvanced Astronomy for HELIophysics) is a small-class
  (500 kg) low-budget (50 MEuro) satellite mission for the study of
  the solar photosphere and the chromosphere and for monitoring solar
  flare emission. ADAHELI's design has completed its Phase-A feasibility
  study in December 2008, in the framework of ASI's (Agenzia Spaziale
  Italiana) 2007 "Small Missions" Program (calling for two missions at
  50 MEeuros each, plus the launch budget). ADAHELI's main purpose is
  to explore Sun's lower atmosphere in the near-infrared, a region so
  far unexplored by solar observations from space. ADAHELI will carry
  out observations of the solar photosphere and of the chromosphere at
  high-temporal rate and high spatial and spectral resolutions. ADAHELI
  will contribute to the understanding of Space Weather through the
  study of particle acceleration during flares. A radiometer operating
  in the millimeter radio band will continuously monitor the solar disk,
  throughout the spacecraft's life time. ADAHELI's baseline instruments
  are a 50-cm high-resolution telescope operating in the visible and
  the near-infrared, and a lightweight full-disk radiometer operating at
  millimeter wavelengths (90 GHz). The core of the telescope's focal plane
  suite is the spectral imager based on two Fabry-Perot interferometers,
  flying for the first time on a solar mission. The instrument
  will return fast-cadence, full bi-dimensional spectral images at
  high-resolution, thus improving on current slit-scan, mono-dimensional
  architectures. Moreover, the possibility of working in polarized light
  will enable full 3D magnetic field reconstruction on the photosphere
  and the chromosphere. An optional instrumental package is also being
  proposed to further extend ADAHELI's scope: a full-disk telescope for
  helioseismology based on a double Magneto-Optical Filter, a Neutral
  Particle Analyzer for magnetospheric research, an Extreme Ultraviolet
  imaging and spectro-radiometry instrument. These options fall outside
  the prescribed budget. ADAHELI, flying a Sun-Synchronous orbit at 800
  km, will perform continuous, long-duration (4-h), daily acquisitions,
  with the possibility of extending them up to 24 h. ADAHELI's operating
  life is two years, plus one extension year. Launch would be nominally
  planned for 2014.

Title: The ADAHELI Solar Mission
Authors: Berrilli, F.; Velli, M.; Roselli, L.; Bigazzi, A.; Moretti,
   P. F.; Romoli, M.; Orsini, S.; Cavallini, F.; Greco, V.; Carbone,
   V.; Consolini, G.; Di Mauro, M. P.; Ermolli, I.; Pietropaolo, E.;
   Romano, P.; Ventura, P.; White, S. M.; Zuccarello, F.; Cauzzi, G.;
   Valdettaro, L.
Bibcode: 2008ESPM...12..6.6B
Altcode:
  ADAHELI (Advanced Astronomy for HELIOphysics) is an Italian Space
  project for the investigation of solar photospheric and chromospheric
  dynamics, via high-resolution spectro-polarimetric observations in the
  near-infrared spectral range. The mission has been financed for phase
  A study in the framework of ASI Italian Space Agency Small Missions
  Program call of September 2007. <P />Four fields have been selected
  to highlight the specific benefits of ADAHELI scientific payload: 1)
  Photospheric and chromospheric dynamics and structure, 2) Emergence and
  evolution of solar active regions and solar irradiance, 3) Chromospheric
  and corona heating and turbulence, 4) Solar flares in the millimeter
  wavelength region. <P />The principal science instrument, ISODY, is
  a 50 cm solar telescope equipped with an innovative Focal Plane Suite
  composed of a spectro-polarimetric imager, based upon two Fabry-Perot
  interferometers operating in the NIR regions around 845nm and 1083nm, a
  broad band imager, and a correlation tracker used as image stabilization
  system. <P />Designed Mission Profiles for ADAHELI intend to achieve
  continuous high-spectral and spatial resolution observations of the
  Sun for a routine duration of 4 hours with a goal to be extended to
  24 hours. <P />ADAHELI also carries MIOS, a millimeter wavelengths
  radiometer operating at around 90 GHz for flare detection. <P />The
  ADAHELI payload's instrument suite integrates and complements, without
  overlap, the present major objectives of ESA, NASA and the International
  Living with a Star program, in particular Solar Dynamics Observatory,
  PICARD, Solar Orbiter, and the Solar Probe missions. <P />Proposals
  for optional instruments are also under evaluation: DIMMI-2h, a
  double channel MOF based full disk imager operating at 589nm and
  770nm, allowing high temporal resolution velocity and magnetic field
  measurements; EISR a two channel spectrometer operating in the 50-130
  nm wavelength range, and NPA, an in-situ Neutral Particle Analyzer
  to detect Energetic Neutral Atoms (ENA). Science objectives related
  to optional instruments include: solar high and low-degree p modes
  oscillations, EUV solar structures and variability, solar gravitational
  red-shift measurement, detection of ENA originating from the plasma
  region in the Earth's magnetosphere and undergoing reflection from
  the Earth's atmosphere.

Title: Characterization of Fabry-Perot interferometers and
    multi-etalon transmission profiles. The IBIS instrumental profile
Authors: Reardon, K. P.; Cavallini, F.
Bibcode: 2008A&A...481..897R
Altcode:
  Aims: Properly characterizing Fabry-Perot interferometers (FPI) is
  essential for determining their effective properties and evaluating
  the performance of the astronomical instruments in which they are
  employed. Furthermore, in two-dimensional spectrographs where multiple
  FPI are used in series, the actual distribution of plate separation
  errors will be crucial for determining the resulting transmission
  profiles. We describe techniques that address these issues utilizing
  the FPI of IBIS, a solar bidimensional spectrometer installed at the
  Dunn Solar Telescope. <BR />Methods: A frequency-stabilized He-Ne
  laser was used in three different optical layouts to measure the
  spatially-resolved transmission of the FPI. Analyzing the shape and
  wavelength shift of the observed profiles allows the characteristics of
  the cavity errors and the interferometer coating to be determined. <BR
  />Results: We have measured the spatial distribution of the large-scale
  plate defects, which shows a steep radial trend, as well as the
  magnitude of the small-scale microroughness. We also extracted
  the effective reflectivity and absorption of the coating at the
  laser line wavelength for both interferometers. <BR />Conclusions:
  These techniques, which are generally applicable to any Fabry-Perot
  interferometer, provide the necessary information for calculating
  the overall instrumental profile for any illuminated area of the
  interferometer plates. Accurate knowledge of the spectral transmission
  profile is important, in particular when using inversion techniques
  or in comparing observations with simulated data.

Title: The solar chromosphere at high resolution with IBIS. I. New
    insights from the Ca II 854.2 nm line
Authors: Cauzzi, G.; Reardon, K. P.; Uitenbroek, H.; Cavallini, F.;
   Falchi, A.; Falciani, R.; Janssen, K.; Rimmele, T.; Vecchio, A.;
   Wöger, F.
Bibcode: 2008A&A...480..515C
Altcode: 2007arXiv0709.2417C
  Context: The chromosphere remains a poorly understood part of the solar
  atmosphere, as current modeling and observing capabilities are still
  ill-suited to investigating its fully 3-dimensional nature in depth. In
  particular, chromospheric observations that can preserve high spatial
  and temporal resolution while providing spectral information over
  extended fields of view are still very scarce. <BR />Aims: In this
  paper, we seek to establish the suitability of imaging spectroscopy
  performed in the Ca II 854.2 nm line as a means of investigating
  the solar chromosphere at high resolution. <BR />Methods: We utilize
  monochromatic images obtained with the Interferometric BIdimensional
  Spectrometer (IBIS) at multiple wavelengths within the Ca II 854.2 nm
  line and over several quiet areas. We analyze both the morphological
  properties derived from narrow-band monochromatic images and the
  average spectral properties of distinct solar features such as network
  points, internetwork areas, and fibrils. <BR />Results: The spectral
  properties derived over quiet-Sun targets are in full agreement with
  earlier results obtained with fixed-slit spectrographic observations,
  highlighting the reliability of the spectral information obtained
  with IBIS. Furthermore, the very narrowband IBIS imaging reveals very
  clearly the dual nature of the Ca II 854.2 nm line. Its outer wings
  gradually sample the solar photosphere, while the core is a purely
  chromospheric indicator. The latter displays a wealth of fine structures
  including bright points akin to the Ca II H{2V} and K{2V} grains, and
  as fibrils originating from even the smallest magnetic elements. The
  fibrils occupy a large fraction of the observed field of view, even
  in the quiet regions, and clearly outline atmospheric volumes with
  different dynamical properties, strongly dependent on the local magnetic
  topology. This highlights how 1D models stratified along the vertical
  direction can provide only a very limited representation of the actual
  chromospheric physics. <BR />Conclusions: Imaging spectroscopy in the
  Ca II 854.2 nm line currently represents one of the best observational
  tools for investigating the highly structured and highly dynamical
  chromospheric environment. A high-performance instrument such as IBIS
  is crucial in achieving the necessary spectral purity and stability,
  spatial resolution, and temporal cadence. <P />Two movies are only
  available in electronic form at http://www.aanda.org

Title: IBIS: A New Post-Focus Instrument for Solar Imaging
    Spectroscopy
Authors: Cavallini, F.
Bibcode: 2006SoPh..236..415C
Altcode:
  A new instrument for solar bi-dimensional spectroscopy, the
  Interferometric BIdimensional Spectrometer (IBIS), has been successfully
  installed at the Dunn Solar Telescope of the National Solar Observatory
  (USA-NM) in June 2003. This instrument is essentially composed of a
  series of two Fabry-Perot interferometers and a set of narrow-band
  interference filters, used in a classic mount and in axial-mode. It
  has been designed to take monochromatic images of the solar surface
  with high spectral (R ≥ 200 000), spatial ≃ 0.2″), and temporal
  resolution (several frames s<SUP>−1</SUP>). IBIS has a circular field
  of view, 80″ in diameter and, with suitable interference filters,
  it can be used in the wavelength range 580 - 860 nm. The wavelength
  stability of the instrumental profile is very high, the maximum
  drift in 10 hours amounting to ≃10 m s<SUP>−1</SUP>. In this
  paper the criteria used in the design and the expected instrumental
  characteristics are described.

Title: The Interferometric Bidimensional Spectrometer (IBIS)
Authors: Cauzzi, Gianna; Cavallini, F.; Reardon, K.; Berrilli, F.;
   Rimmele, T.; IBIS Team
Bibcode: 2006SPD....37.0608C
Altcode: 2006BAAS...38..226C
  The Interferometric Bidimensional Spectrometer (IBIS) is an advanced
  instrument for imaging spectroscopy installed at the Dunn Solar
  Telescope at NSO/Sacramento Peak. The instrument has been constructed by
  a consortium of italian institutes and allows for observations of the
  photosphere and chromosphere at high spatial, spectral, and temporal
  resolution. Such observations are essential for performing spatial
  and spectral comparisons with numerical simulations. We will present
  some of the performance characteristics of the instrument and show some
  examples of the IBIS data. We will also show some initial results of the
  recently tested polarimetric mode. IBIS is available for community use
  as a facility instrument of NSO.IBIS has been funded by the Italian
  Research Ministry (MIUR), the Italian Institute for Astrophysics
  (INAF), and the Universities of Florence and Rome. Additional support
  is provided by the National Solar Observatory.

Title: High Resolution Spectropolarimetry of Penumbral Formation
    with IBIS
Authors: Reardon, Kevin; Casini, R.; Cavallini, F.; Tomczyk, S.;
   Rouppe van der Voort, L.; Van Noort, M.; Woeger, F.; Socas Navarro,
   H.; IBIS Team
Bibcode: 2006SPD....37.3503R
Altcode: 2006BAAS...38..260R
  We present the results of first spectropolarimetric observations
  made with the Interferometric Bidimensional Spectrometer (IBIS)
  at the NSO/Dunn Solar Telescope. The use of narrowband imaging and
  post-facto reconstruction techniques allows for observations close
  to the diffraction limit of the vector magnetic field. We will show
  observations of the the formation of an individual penumbral filament
  around a small pore. We measure the magnetic field and velocity field
  of the forming penumbral filament. The spectropolarimetric mode of
  IBIS will be available to the community in the fall of 2006.

Title: IBIS instrumental characteristics and first results
Authors: Cavallini, F.; Reardon, K.
Bibcode: 2006MSAIS...9...55C
Altcode:
  The Interferometric BIdimensional Spectrometer (IBIS) was installed in
  June 2003 at the DST/NSO, where it is used in conjuction with a high
  order AO system. IBIS has since proved to be a reliable and versatile
  instrument for performing high resolution observations in both the
  photosphere and chromosphere. We describe here the instrument and its
  performance characteristics especially with respect to the obtainable
  spectral, temporal and spatial resolutions, providing examples of the
  actual observations.

Title: IBIS: Instrument Description and First Results
Authors: Cavallini, F.; IBIS Team
Bibcode: 2004AAS...204.3709C
Altcode: 2004BAAS...36R.710C
  In June 2003, the Inferometric Bidimensional Spectrometer (IBIS)
  was installed at the Dunn Solar Telescope at Sacramento Peak
  Observatory. This new instrument uses two Fabry-Perot interferometers to
  permit the detailed sampling (30-40 mÅ FWHM) of solar spectral lines
  over an 80 arcsecond diameter field of view in the range 5800-8600
  Å. IBIS operates in combination with the NSO adaptive optics system,
  allowing it to achieve diffraction-limited images, while being able to
  scan through an entire spectral line in 5-10 seconds. The instrument
  design placed a premium on reducing parasitic spectral light and
  maintaining a stable and uniform spectral transmission profile across
  the field of view. <P />We present the operational characteristics
  of the instrument as determined from laboratory calibrations as
  well as tests performed during the initial observing runs with the
  instrument. We provide examples of the datasets obtained during these
  first observing runs and some preliminary results gleaned from these
  data. We also indicate some of the scientific programs for which this
  instrument is ideally suited.

Title: IBIS Observations of Quiet Sun Photosphere - Velocity Structure
    from Fe I 7090.4 Å
Authors: Janßen, Katja; Cauzzi, Gianna; Falchi, Ambretta; Cavallini,
   Fabio; Reardon, Kevin
Bibcode: 2004IAUS..223..631J
Altcode: 2005IAUS..223..631J
  In our contribution we introduce the new Interferometric BIdimensional
  Spectrometer (IBIS) and present the first results on bisector velocities
  of two dimensional spectral scans in FeI 7090.4 Å comparing granules
  and intergranular regions.

Title: Recent results from IBIS
Authors: Cavallini, F.; Baffa, C.; Reardon, K.; Berrilli, F.;
   Cantarano, S.; Egidi, A.
Bibcode: 2003MmSAI..74..796C
Altcode:
  IBIS (Interferometric BIdimensional Spectrometer) is a new instrument
  for solar bidimensional spectroscopy. It essentially consists
  of two Fabry-Perot interferometers, piezo-scanned and capacity
  servo-controlled, used in classic mount and in axial-mode, in series
  with a set of narrow-band interference filters. This instrument will
  operate on a large field of view (80") and on a large wavelength
  range (580 - 860 nm), with high spectral, spatial and temporal
  resolution. IBIS, developed to become one of the focal plane instruments
  of THEMIS, has been completed in its essential form and some tests have
  been already performed. It is now possible therefore to compare expected
  with measured values of the more relevant instrumental parameters.

Title: Characterization of the IBIS Transmission Profile
Authors: Reardon, K.; Cavallini, F.
Bibcode: 2003MmSAI..74..815R
Altcode:
  We describe the techniques used to characterize the components of
  the IBIS instrument in the laboratory in order to determine the
  operational performance of the completed instrument. In particular,
  we have measured the surface and coating irregularities of the two
  Fabry-Perot interferometers at the heart of IBIS. From this we construct
  a theoretical transmission profile for the instrument and relate that
  to the accuracy that can be obtained in measurements of the Sun.

Title: IBIS (Interferometric BIdimensional Spectrometer)
Authors: Cavallini, F.
Bibcode: 2002ESASP.477..585C
Altcode: 2002scsw.conf..585C
  IBIS is a new instrument for solar bidimensional spectroscopy, now under
  construction at the Arcetri Astrophysical Observatory. It essentially
  consists in two Fabry-Perot interferometers, used in classic mount
  and in axial mode, in series with a set of narrow-band interference
  filters. This instrument will operate on a large wavelength range,
  with high spectral, spatial and temporal resolution. Some preliminary
  results, obtained during the ongoing evaluation of the instrumental
  set-up will be described.

Title: IBIS: a new instrument for solar bidimensional spectroscopy
Authors: Cavallini, F.; Berrilli, F.; Cantarano, S.; Egidi, A.
Bibcode: 2001MmSAI..72..554C
Altcode:
  IBIS is a new instrument for solar bidimensional spectroscopy, now
  under construction in Arcetri, which will operate on a large field
  of view and on a large wavelength range, with high spectral, spatial
  and temporal resolution. When completed in 2002, it will be one of the
  leading instruments for solar research, well suited for new generation
  telescopes such as THEMIS.

Title: IBIS: A Purely Interferometric Instrument for Solar
    Bidimensional Spectroscopy
Authors: Cavallini, F.; Berrilli, F.; Cantarano, S.; Egidi, A.
Bibcode: 2000ESASP.463..607C
Altcode: 2000sctc.proc..607C
  No abstract at ADS

Title: Italian panoramic monochromator for the THEMIS telescope:
    the first results and instrument evaluation
Authors: Cavallini, Fabio; Berrilli, Francesco; Caccin, Bruno;
   Cantarano, Sergio; Ceppatelli, Guido; Egidi, Alberto; Righini, Alberto
Bibcode: 1998SPIE.3355..940C
Altcode:
  We briefly describe the design and the characteristics of the Italian
  Panoramic Monochromator installed at the focal plane of the THEMIS
  telescope built in Izana by a joint venture of the French and Italian
  National Research Councils. The Panoramic Monochromator substantially
  is a narrow band filter (approximately equals 22 mAngstrom bandwidth)
  tunable on the visible spectrum for quasi simultaneous bidimensional
  spectrometry of the solar atmosphere. The narrow bandwidth is
  obtained by using a non standard birefringent filter and a Fabry Perot
  interferometer mounted in series. This assembly has the advantage of
  the spectral purity of one channel of the Fabry Perot interferometer
  and a very large free spectral range. Moreover the spectral stability
  depends on the interferometer, the environment of which may be carefully
  controlled. The design of this instrument is not really new, but,
  only now it has been possible to build it thanks to the development
  of servo controlled Fabry Perot interferometers, which are stable in
  time and may easily be tuned. The system seems to perform well. It is
  stable in wavelength and the spectral pass band and stray light are
  within the expected values, as it may be deduced by very preliminary
  tests performed at the THEMIS Telescope and in Arcetri (Firenze) at the
  'G. B. Donati' solar tower.

Title: The Italian Panoramic Monochromator
Authors: Cavallini, F.
Bibcode: 1998A&AS..128..589C
Altcode:
  A new instrument for solar bidimensional spectroscopy, the Italian
  Panoramic Monochromator (IPM), has been recently installed on the
  Telescope Heliographique pour l'Etude du Magnetisme et des Instabilites
  de l'atmosphere Solaire (THEMIS), the French-Italian solar telescope
  built in Tenerife (Canary Islands). On a square field 33''x 33'',
  this instrument allows one to obtain monochromatic images of the solar
  surface with high spectral resolution ({cal R} &gt;= 256000 at 5500
  Angstroms), preserving all the spatial resolution delivered by the
  telescope ( =~ 0.2''). The wavelength stability of the instrumental
  profile is very high, the maximum drift in 10 hours amounting to about
  10 ms(-1) .

Title: Purely interferometric solar bidimensional spectroscopy
Authors: Cavallini, F.
Bibcode: 1998MmSAI..69..627C
Altcode:
  No abstract at ADS

Title: The IPM-Italian Panoramic Monochromator operating at the
    THEMIS telescope.
Authors: Cavallini, F.; Ceppatelli, G.; Righini, A.; Berrilli, F.;
   Caccin, B.; Cantarano, S.; Egidi, A.
Bibcode: 1997cpyt.conf..119C
Altcode:
  From April 20, 1997 the Italian Panoramic Monochromator (henceforth IPM)
  will be the first operating mode of the THEMIS telescope. It basically
  consists of a Fabry-Perot interferometer mounted in tandem with an
  universal birefringent filter. The image acquisition system consists
  of two CCD cameras controlled and read-out by dedicated electronics and
  personal computers. One of these cameras acquires a simultaneous white
  light image for the application of off-line destretching procedures
  in order to reduce seeing effects. An optical link connects the CCD
  camera and the PCs while the handshaking and the data transfer between
  the PCs and the work station controlling the IPM is performed via LAN
  and IEE488 bus.

Title: A rheological model for anelastic anisotropic media with
    applications to seismic wave propagation
Authors: Carcione, José M.; Cavallini, Fabio
Bibcode: 1994GeoJI.119..338C
Altcode:
  No abstract at ADS

Title: The height dependence of intensity and velocity structures
    in the solar photosphere
Authors: Salucci, G.; Bertello, L.; Cavallini, F.; Ceppatelli, G.;
   Righini, A.
Bibcode: 1994A&A...285..322S
Altcode:
  Results about a statistical analysis of the solar granulation, obtained
  by analyzing a series of narrow band (20 mA FWHM) images in the 6162.18
  A CaI photospheric line, are presented. The observations have been
  performed at the Vacuum Solar Tower of the National Solar Observatory
  at Sac. Peak (NM-USA) in 1988, using a Fabry-Perot interferometer and a
  Universal Birefringent Filter mounted in tandem. We computed coherence,
  phase and power spectra of intensity and velocity fields in a 27"x27"
  quiet region at the disk center. Energy spectra, plotted in the usual
  log-log coordinates, clearly show a linear shape for wavenumbers between
  3 and 10 Mm^-1^. The exponent is -17/3: it does not significatively vary
  within the considered photospheric layers and largely differs from both
  the theoretical value and the results of previous 1-D observations. This
  result indicates that in the photosphere we are in presence of a
  redistribution of the convective energy through a cascade from larger
  granules to smaller ones, although the size distribution does not follow
  the Kolmogorov law. The physical processes involved in the granulation
  have been investigated by studying the height dependence of coherence
  and phase spectra of Velocity-Velocity (V-V) and Velocity-Intensity
  (V-I) fields. We find that the photosphere is divided in two regions:
  the velocity structures existing in the lower layers (first region)
  are convective and extend up to about 170 km. The decay of these
  granular motions generates well correlated velocity structures in the
  second region (height range 170-400 km), at spatial frequencies 5-10
  Mm^-1^. In this region, moreover, the coherence moderately increases
  with height, while the phase is stable around +/-180°. This means
  that velocity and intensity fields are predominantly anticorrelated,
  as expected for gravity waves.

Title: The THEMIS telescope
Authors: Rayrole, J.; Mein, P.; Cavallini, F.
Bibcode: 1994ASIC..433..507R
Altcode:
  No abstract at ADS

Title: The influence of the stray light in the solar image on the
    Fraunhofer line profiles
Authors: Barducci, A.; Cavallini, F.; Ceppatelli, G.; Righini, A.
Bibcode: 1994A&A...281..955B
Altcode:
  In the solar spectroscopy the scattered light produced by the Earth's
  atmosphere and telescope optics may bias the result of spectral
  and photometric measurements. The problem of correcting the spectral
  observations from the stray light has assumed a great importance in the
  studies of large-scale motion into the solar atmosphere. Nevertheless,
  it is not yet known how the light smearing may affect the observed
  values of the relevant parameters of the Fraunhofer lines, with the
  exception of their wavelengths (the so called 'velocity error') which
  has been already examined. In this paper we discuss the effects of the
  light scattering in the solar image on the spectroscopic measurements
  and we discuss some data reduction techniques. Moreover we calculate
  the analytical distribution of the velocity error over the solar disk,
  obtaining new insights on the understanding of the solar rotation
  peculiarities.

Title: Project for the installation of the panoramic monochromator
    to the THEMIS solar telescope
Authors: Cavallini, F.
Bibcode: 1993MmSAI..64..764C
Altcode:
  No abstract at ADS

Title: First measurements of solar oscillations with the THEMIS
    panoramic monochromator
Authors: Berrilli, F.; Caccin, B.; Cantrano, S.; Cavallini, F.;
   Ceppatelli, G.; Egidi, A.; Francia, P.; Pietropaolo, E.; Righini, A.
Bibcode: 1993MmSAI..64..781B
Altcode:
  No abstract at ADS

Title: High-resolution spectroscopic imaging of the Sun with a
    Universal Birefringent filter and a Fabry-Perot interferometer.
Authors: Cavallini, F.; Ceppatelli, G.; Righini, A.; Berrilli, F.;
   Caccin, B.; Cantarano, S.; Egidi, A.; Francia, P.; Pietropaolo, E.
Bibcode: 1992NCimC..15..509C
Altcode:
  The authors describe an optical device consisting of a Universal
  Birefringent Filter and a Fabry-Perot interferometer used in tandem
  to obtain monochromatic images of the Sun in the visible spectrum
  (between 4200 and 7000 Å). They give an account of the preliminary
  results obtained by measuring the global velocity field on the solar
  photosphere. These results show that the instrument is well suited
  for global oscillation measurements.

Title: High resolution granulation spectrophotometry with a UBF and
    a FP interferometer in tandem.
Authors: Salucci, G.; Bertello, L.; Righini, A.; Bonaccini, D.;
   Cavallini, F.; Ceppatelli, G.
Bibcode: 1992ESASP.344..157S
Altcode: 1992spai.rept..157S
  Recent studies have shown that in the solar granulation, granules sizes
  lower than 3″may be considered as turbulent eddies. However this
  result is in contradiction with morphological studies carried out by
  other authors. In this paper the authors analyse in the spatial domain
  the autocorrelation and crosscorrelation functions of the velocity
  and of the intensity fields at several depths in the solar atmosphere,
  using narrow band filtergrams obtained at Sacramento Peak Observatory
  Vacuum Tower Telescope with a UBF and a FP interferometer mounted in
  tandem. The results show that the granular motion is turbulent for
  heights larger than 170 km while at lower heights is convective.

Title: About Spectroscopic Measurements of the Solar Meridional Motion
Authors: Cavallini, F.; Ceppatelli, G.; Righini, A.
Bibcode: 1992A&A...254..381C
Altcode:
  A large number of spectroscopic measurements of meridional mass
  motion on the Sun has been carried out in the past. The results are
  rather contradictory, although a 10 ms<SUP>-1</SUP> poleward flow
  might be inferred. Some authors have pointed out that the so called
  "meridional motion" might be ascribed to a latitudinal dependence of
  the convective flux. In this paper we describe new observations carried
  out with the spectro-interferometer installed at the G.B. Donati Solar
  Tower in Arcetri: these measurements have been performed using lines
  having either similar or very different physical parameters in order
  to disentangle convective effects from true mass flows. We discuss the
  results and we conclude that the great variety of "meridional motions"
  so far observed by spectroscopic means may be ascribed to an intrinsic
  variability of the meridional flow pattern and in part to the presence
  of a large scale velocity field.

Title: The solar aureola - Theory and observations
Authors: Barducci, A.; Righini, A.; Cavallini, F.; Ceppatelli, G.
Bibcode: 1990A&A...240..203B
Altcode:
  The stray light, which originates in the earth atmosphere and in the
  telescope optics, produces a 'cross-talk' between spectral as well
  as intensity information held in different picture elements. In this
  paper the mathematical formulation of the scattering processes and
  their dependence on the wavelength and on the zenith distance of the
  source are discussed and compared with aureola observations carrried
  out at the G.B. Donati Solar Tower in Arcetri. The analysis confirms
  the zenith and wavelength dependence of the relevant aureola parameters
  as given by the theory, and shows that the logarithmic description
  of the aureola intensity, sometime given by other authors, correctly
  applies also to the Arcetri measurements. This result suggests the
  possibility of evaluating the stray light effects on spectroscopic
  and photometric observations stemming from a few aureola measurements
  performed at given distances from the solar limb.

Title: Depth dependence of the intensity-velocity phase difference
    in the solar '5-min' oscillations
Authors: Alamanni, N.; Bertello, L.; Righini, A.; Cavallini, F.;
   Ceppatelli, G.
Bibcode: 1990A&A...231..518A
Altcode:
  Previous measurements carried out on four Fe I photospheric lines have
  suggested that the different oscillating power observed on the blue and
  red line flanks is produced by the intensity-velocity phase lag in the
  '5-min' waves. Former measurements and new additional observations on
  the 6149.2 A Fe II and 6162.2 A Ca I lines have been used to evaluate
  more accurately the dependence of this intensity-velocity phase
  difference on the photospheric height. A nonadiabatic and nonisothermal
  bidimensional model of the thermodynamic fluctuations induced in the
  photosphere by the high degree p-modes suggests that radiative damping
  might explain the observed line profile oscillations.

Title: CA I 6162 A line oscillations observed in a solar active region
Authors: Alamanni, N.; Righini, A.; Cavallini, F.; Ceppatelli, G.
Bibcode: 1990A&A...228..517A
Altcode:
  The effect of the magnetic field on the high degree p-modes in the
  solar atmosphere is still controversial, both from the theoretical
  and the experimental point of view. The temporal behavior of the 6162
  A Ca I line profile in an active region has been observed with the
  spectrointerferometer of the Arcetri solar tower. It is found that
  the presence of magnetic field suppresses several modes of oscillation
  and that the line oscillates almost 'rigidly'.

Title: High resolution solar bidimensional spectroscopy with
    a universal birefringent filter in tandem with a Fabry-Perot
    interferometer
Authors: Bonaccini, D.; Righini, A.; Cavallini, F.; Ceppatelli, G.
Bibcode: 1989A&A...217..368B
Altcode:
  The design of an optical device consisting of a universal birefringent
  filter and a Fabry-Perot interferometer to obtain monochromatic images
  of the solar atmosphere with a spectral resolving power of about 300,000
  is discussed. The instrument may be continuously tuned between 4200 A
  and 7000 A and, using commercially available Fabry-Perot, may reach a
  wavelength stability of about 0.1 mA. This system preserves all the
  spatial resolution delivered by the telescope and limits the size
  of the observable field to a maximum of 400 widths of the telescope
  diffraction pattern.

Title: Polarization properties of a `Zeiss-type' coelostat: The case
    of the solar tower in Arcetri
Authors: Capitani, C.; Landi Degl'Innocenti, E.; Cavallini, F.;
   Ceppatelli, G.; Landi Degl'Innocenti, M.; Landolfi, M.; Righini, A.
Bibcode: 1989SoPh..120..173C
Altcode:
  A theoretical model of the polarization properties of a `Zeiss-type'
  coelostat is presented and discussed in detail. The Muller matrix
  describing the modification of the Stokes vector of the incident
  radiation as a result of the multiple reflections on the coelostat
  mirrors is derived as a function of the solar coordinates, the
  geometrical configuration of the coelostat, and the parameters defining
  the optical properties of the mirrors. These parameters, or more
  particularly, the index of refraction n and the extinction coefficient
  k, have been evaluated by means of laboratory measurements performed
  on a series of specimens having characteristics similar to those of
  the coelostat mirrors. The geometry of the coelostat configuration
  is described in full detail. The theoretical model has been then
  particularized to the case of the Donati Solar Tower in Arcetri,
  and some experimental measurements have been performed to check the
  correctness of the model. These measurements show the basic adequacy
  of the mathematical model, although some offset terms are found in
  the Stokes parameters U and V.

Title: Line Bisectors In and Out Magnetic Regions
Authors: Cavallini, F.; Ceppatelli, G.; Righini, A.
Bibcode: 1989ASIC..263..283C
Altcode: 1989ssg..conf..283C
  No abstract at ADS

Title: Profile variations of some photospheric lines as observed in
    active regions across the solar disk
Authors: Cavallini, F.; Ceppatelli, G.; Righini, A.
Bibcode: 1988A&A...205..278C
Altcode:
  Some photospheric lines have been observed in active regions at
  different distances from the solar disk center. Assuming that the
  line weakening monotonically changes with the changing of the magnetic
  field intensity, it is established for the observed lines how the line
  width, line asymmetry and line shift vary with the magnetic field. In
  particular, near the disk center, an increasing red-shift of the higher
  part of the lines is observed with the increasing of the field, while,
  at the bottom of a strong line, a small blue-shift is observed. These
  results may be interpreted as due to the fading of the convection in
  active regions produced by the magnetic field.

Title: Bounds on the eigenvalues of the planetary-scale baroclinic
    instability problem
Authors: Cavallini, Fabio; Crisciani, Fulvio; Mosetti, Renzo
Bibcode: 1988DyAtO..12...71C
Altcode:
  In the framework of the linear baroclinic instability problem for
  planetary geostrophic flows, bounds on the related complex eigenvalues
  are deduced. The main feature of this result is the independence
  of these bounds from the latitude and the density stratification,
  so that it generalizes the results of previous work on the subject.

Title: The spectro-interferometer of the Arcetri Solar Tower
Authors: Cavallini, F.; Ceppatelli, G.; Meco, M.; Paloschi, S.;
   Righini, A.
Bibcode: 1987A&A...184..386C
Altcode:
  The authors describe the spectro-interferometer installed at the
  Arcetri Observatory Solar Tower. This instrument basically consists
  of a Fabry-Perot interferometer mounted in tandem with a medium sized
  grating spectrograph, acting as order sorter. This mounting allows
  the measurement of solar absorption lines in the range 5500 - 6500
  Å with high wavelength stability (0.08 mÅ rms in 12 h) and high
  spectral resolution (900,000 at 6328 Å). An image guider allows
  the pointing of an assigned solar region with an accuracy better
  than 2arcsec rms. This instrument, suitable for investigating line
  shifts and asymmetries, has been extensively used for studying such
  solar problems as meridional mass motions, line asymmetry "5-min"
  oscillations, and convective effects in solar active regions.

Title: 5-min oscillations in the wings and bisectors of solar
    photospheric Fe I lines
Authors: Cavallini, F.; Ceppateli, G.; Righini, A.; Alamanni, N.
Bibcode: 1987A&A...173..161C
Altcode:
  Former observations carried out at the center of the solar disk on three
  Fe I photospheric lines have shown that, during the 5-min oscillation,
  the bisector and the line flanks show an oscillation amplitude
  decreasing in a different way from the line core to the continuum. New
  observations, obtained in a magnetically insensitive line, in and
  outside the disk center, confirm the previous findings. From these
  and the former measurements it follows that the ratio between the
  V<SUB>rms</SUB> of the blue and the red flanks in the observed
  lines depends on the height in the photosphere. This result may be
  qualitatively interpreted as due to the coupling of the velocity and
  brightness oscillations in the 5-min waves, and its height dependence
  as due to a phase effect.

Title: Interpretation of shifts and asymmetries of Fe I lines in
    solar facular areas
Authors: Cavallini, F.; Ceppatelli, G.; Righini, A.
Bibcode: 1987A&A...173..155C
Altcode:
  An attempt is made to evaluate the effect in active regions of
  the suppression of convective phenomena, and of the different line
  profiles arising from the fluxtubes on the spatially averaged line
  profiles. Through use of a multi-column model, the asymmetries and
  shifts of three Fe I photospheric lines (g not equal to 0), observed in
  facular areas have been analyzed. It is assumed that the facula consists
  of magnetic fluxtubes (1.5 kG field) with a zero downflow embedded in
  an atmosphere where the convection is partially inhibited. This model
  satisfactorily reproduces the observed line shifts and asymmetries
  for all three lines.

Title: Drift Velocities in Flux Tubes Inferred by Spatially Averaged
    Line Bisectors
Authors: Cavallini, F.; Ceppatelli, G.; Righini, A.
Bibcode: 1987rfsm.conf..110C
Altcode:
  The bisectors of the spatially averaged line profiles observed in
  active regions may be a useful tool to investigate the drift velocities
  within flux tubes. The authors show that a simple heuristic model may
  account for the major effects observed in some Fe I line bisectors in
  active regions. The model satisfactorily reproduces the behaviour of
  the line shifts and asymmetry with the increasing magnetic field. The
  authors assume that an active region consists of static magnetic
  flux tubes embedded in an atmosphere where the convection is partially
  inhibited. However one cannot exclude a slight downflow up to 250 m/s in
  the flux tubes. The case of non static flux tubes showing downflows as
  large as 1000 - 2000 m/s with disappointing results are also considered.

Title: Meridional Flows and Latitudinal Dependence of the Convection
Authors: Cavallini, F.; Ceppatelli, G.; Righini, A.
Bibcode: 1987rfsm.conf...21C
Altcode:
  Theoretical studies on the differential rotation of the Sun require a
  surface meridional flow. Recent measurements of the drift of tracers
  suggest that this flow must be lower than 1.4 m/s, while spectroscopical
  measurements give contradictory results. These measurements may be
  strongly affected by different convection between equator and poles
  produced by the magnetic field which locally inhibits convective
  effects. In the last years several measurements of meridional motion
  have been performed at the Arcetri Solar Tower. The authors discuss
  from a critical point of view the obtained results.

Title: A solar filter for two dimensional spectroscopy
Authors: Bonaccini, Domenico; Righini, A.; Cavallini, F.; Ceppatelli,
   G.
Bibcode: 1987LIACo..27..235B
Altcode: 1987oahp.proc..235B
  Not Available.

Title: Solar limb effect and meridional flow - Results on the Fe I
    lines at 5569.6 A and 5576.1 A
Authors: Cavallini, F.; Ceppatelli, G.; Righini, A.
Bibcode: 1986A&A...163..219C
Altcode:
  A description is given of an investigation on the center-to-limb
  variation of the line asymmetry and shift along the polar and equatorial
  diameters of the sun on two Fe I photospheric lines. The observations,
  obtained with the Fabry-Perot spectrointerferometer installed at the
  Donati Solar Tower Telescope in Arcetri, do not show any significant
  latitudinal dependence of the line asymmetry. Instead, the limb shift
  curves obtained along the polar diameter systematically differ from
  those obtained along the equator. This difference, if interpreted as
  due to a surface mass flow, implies a poleward meridional motion with
  a maximum of about 50 m/s at 45 deg of latitude in both hemispheres. A
  detailed analysis of these and previous results suggests that the so
  called 'meridional motions', found by spectroscopical means, mainly
  originate from latitudinal effects on the convective line shift, which
  might also be modulated by the activity cycle. This interpretation does
  not exclude the fact that small meridional mass flows are present on
  the sun, like those found from the tracers drifts.

Title: Long-term width and asymmetry variation of some Fe I
    photospheric lines in solar quiet regions at the disk center.
Authors: Cavallini, F.; Ceppatelli, G.; Righini, A.
Bibcode: 1986A&A...158..275C
Altcode:
  Observations obtained in the years 1983 and 1984 at the Donati Solar
  Tower in Arcetri show that at the disk center the asymmetry and width
  of three Fe I photospheric lines show a long term variation. These
  results are in agreement with previous full disk observations of
  secular trends in asymmetry and equivalent width.

Title: Prospects for an orbital determination and capture cell
    experiment
Authors: Cavallini, F.; Ceppatelli, G.; Righini, A.; Alamanni, N.
Bibcode: 1986A&A...156..310C
Altcode:
  Recent measurements of the 7699 Å K I line by other authors have shown
  that the line asymmetry, during the 5-min oscillations, varies in an
  tiphase with the line shift. We have measured, at the center of the
  solar disk, the bisector variations of three Fe I photospheric lines at
  6297.8 Å, 6301.5 Å and 6302.5 Å. The oscillating power of the line
  bisectors and of the line flanks is distributed in several modes, the
  highest one is at 3.45mHz. The power decreases along the bisector from
  the line core to the continuum, confirming previous results on the 7699
  Å K I line. The oscillating power, at equal intensity levels in all
  the three observed lines, is generally different in the two line flanks,
  and it decreases differently from the line core to the continuum.

Title: Meridional and equatorial center-to-limb variation of the
    asymmetry and shift of three Fe I solar photospheric lines around
    6300 A
Authors: Cavallini, F.; Ceppatelli, G.; Righini, A.
Bibcode: 1985A&A...150..256C
Altcode:
  In this paper we describe an investigation on the center-to-limb
  variation of the line asymmetry and shift along the polar and
  equatorial diameters of the Sun, carried out on the Fe I photospheric
  lines at 6297.8 Å, 6301.5 Å, and 6302.5 Å. In particular we aim at
  ascertaining how much of the so called meridional motion is due to a
  possible latitudinal dependence of the convection, and how much to real
  large scale mass flows. The observations, obtained with the Fabry-Perot
  spectrointerferometer installed at the Donati Solar Tower in Arcetri,
  do not show any significant latitudinal effect on the line bisector
  shapes. The results regarding the latitudinal dependence of the limb
  shift are ambiguous.

Title: Shortterm Profile Variations of Photospheric Lines in Solar
    Quiet Regions at the Disk Center
Authors: Cavallini, F.; Ceppatelli, G.; Righini, A.
Bibcode: 1985tphr.conf...87C
Altcode:
  No abstract at ADS

Title: Terrestrial O2 lines used as wavelength references Experimental
    profiles and asymmetries vs. model computations
Authors: Caccin, B.; Cavallini, F.; Ceppatelli, G.; Righini, A.;
   Sambuco, A. M.
Bibcode: 1985A&A...149..357C
Altcode:
  In order to evaluate wind and pressure effects on telluric lines,
  the profiles and the bisectors of four rotational lines of the
  gamma band is compared with the results of detailed theoretical
  calculations. The analysis is carried out using standard models of
  the terrestrial atmosphere and the molecular data available in the
  literature. In particular, a height-dependent pressure shift of the
  line profile has been included in the calculations, leading to a
  satisfactory agreement with the observations. The computer code for
  line transfer in the earth's atmosphere correctly reproduces also the
  profiles and the bisectors of the same lines obtained at the height of
  the Jungfraujoch, as can be deduced from the Liege Atlas (Delbouille et
  al., 1973). Finally, the line shifts observed by Balthasar et al. (1982)
  are compared with line shifts computed with the present code, including
  wind shifts and pressure shifts. It is found that the amount by which
  the varying asymmetry of the lines may affect wavelength determinations
  depends upon the definition of the line wavelength itself.

Title: Asymmetry and shift of three Fe I photospheric lines in solar
    active regions.
Authors: Cavallini, F.; Ceppatelli, G.; Righini, A.
Bibcode: 1985A&A...143..116C
Altcode:
  The asymmetry and the red shift of three Fe I solar lines around 6300 A
  have been measured in active regions with a Fabry-Perot spectrometer. At
  the disk center, the active region line bisectors are always displaced
  to the red and their shape is heavily modified. This red-shift nearly
  compensates the convective blue-shift for strong magnetic fields,
  suggesting that the inhibition of convection in magnetic regions
  might be responsible for the red-shift instead of the often invoked
  'downdraft'. Moving from the center to the limb, at about 0.56 solar
  radii, the red-shift changes to a slight blue shift. This effect might
  explain, without the need of invoking a poleward meridional flow,
  why the center to limb red-shift of the line wavelengths is found to
  be smaller along the solar equator than along the meridian on large
  ensembles of data.

Title: Solar Two-Dimensional Spectroscopy with Universal Birefringent
    Filters and Fabry-Perot Interferometers
Authors: Bonaccini, D.; Cavallini, F.; Ceppatelli, G.; Righini, A.
Bibcode: 1985LNP...233..118B
Altcode: 1985hrsp.proc..118B
  A bidimensional solar spectrometer that utilizes a Fabry Perot
  interferometer (FPI) and a universal birefringent filter (UBF) and
  operates in the 4200-7000. A region of the spectrum is described. The
  UBF is a chain of nine Lyot elements which are composed of a calcite or
  quartz retarder plate, a lambda/4 achromatic wave plate, and an input
  and output linear polarizer. The telecentric optical interference
  of the system is examined. The high passband wings of the FPI are
  analyzed; an FPI in double-pass configuration is proposed to lower
  the FPI passband wings and improve its contrast.

Title: Short term profile variations of photospheric lines in solar
    quiet regions at the disk center.
Authors: Cavallini, F.; Ceppatelli, G.; Righini, A.; Alamanni, N.
Bibcode: 1985MPARp.212...87C
Altcode:
  The authors study short term profile variations of photospheric
  lines. These asymmetry oscillations might put new constraints on the
  modelling of the line asymmetry forming processes in presence of a
  turbulent regimen.

Title: Preliminary Results About the Bisector of 6301.5 Solar Line
    in Active Regions
Authors: Cavallini, F.; Ceppatelli, G.; Righini, A.
Bibcode: 1984ssdp.conf..334C
Altcode:
  Preliminary results of the observations performed with the Fabry-Perot
  spectrometer of the Arcetri Solar Tower show that the bisector of the
  6301.5 Fe I solar line is red shifted and the C-shape is distorted in
  active regions when compared with that obtained in quiet regions.

Title: Absolute measurement of the bisector of the 6301.5091 Fe I
    line in the solar spectrum
Authors: Cavallini, F.; Ceppatelli, G.; Righini, A.
Bibcode: 1982A&A...109..233C
Altcode:
  In order to test whether differences in results about the shape of
  the 6301.5091 Fe I solar line can be ascribed to temporal fluctuations
  of the line asymmetry or to instrumental effects, measurements of the
  absolute bisector of the line have been obtained with the Fabry-Perot
  interferometer built at the Arcetri Solar Tower. The bisector agrees
  with that previously obtained by Adam et al. (1976). The wavelength
  of the line coincides with previous measurements, suggesting that, at
  the disk center, the line is stable within 5 m/s for an integration
  area of two arcmin. This result also shows that the three telluric
  lines used as wavelength references are stable down to this limit.

Title: Fabry Perot Interferometers for High Resolution Solar
    Spectroscopy
Authors: Cavallini, F.; Ceppatelli, G.; Righini, A.
Bibcode: 1981siwn.conf..243C
Altcode:
  No abstract at ADS

Title: Solar oscillations
Authors: Cavallini, F.; Ceppatelli, G.; Righini, A.
Bibcode: 1980MmSAI..51..611C
Altcode:
  Theoretical and observational problems in the study of solar
  oscillations are reviewed. Consideration is given to models of solar
  pulsations, for which accurate values of initial solar abundances
  and a more complete knowledge of convective zone dynamics are
  required. Measurements of variations in the solar diameter or the
  radial velocity of the center of the solar disk are then discussed,
  and arguments are presented in favor of the terrestrial origin of the
  160-min solar oscillations. The importance of the study of short-period
  (about 5 min) solar oscillations to theories of the solar convective
  zone is also pointed out.

Title: A Fabry Perot spectrometer for measuring solar velocity fields
Authors: Cavallini, F.; Ceppatelli, G.; Barletti, R.; Righini, A.
Bibcode: 1980A&A....85..255C
Altcode:
  A solar spectrometer based on a Fabry-Perot interferometer has been
  developed as an alternative to grating spectrometers for measuring solar
  velocity fields. The spectrometer features high stability and provides
  measurements of velocity fields down to 8 m/s over solar surface areas
  up to two arcmin in diameter. Wavelength drifts of the system are slow
  and predictable, and the results may be rectified by a continuous test
  of the interferometer thickness with a standard wavelength source. Data
  obtained on the bisector of the 6301.508 Fe I line are reported.

Title: H and K (Ca II) emissions as observed in coronal spectrum in
    the July 20, 1963 solar eclipse
Authors: Cavallini, F.; Righini, A.
Bibcode: 1975SoPh...45..291C
Altcode:
  From a detailed analysis of a coronal spectrum taken from a DC-8 jet
  airplane during the Eclipse of 20 July, 1963 a rough model of a coronal
  cold region (T ≈ 10<SUP>5</SUP> K) has been obtained.

