Astronomical site testing in the era of the extremely large telescopes

The quality of astronomical sites is the first step to be considered to have the best performances from the telescopes. In particular, the efficiency of large telescopes in UV, IR, radio etc. is critically dependent on atmospheric transparency. It is well known that the random optical effects induced on the light propagation by turbulent atmosphere also limit telescope’s performances. Nowadays, clear appears the importance to correlate the main atmospheric physical parameters with the optical quality reachable by large aperture telescopes. The sky quality evaluation improved with the introduction of new techniques, new instrumentations and with the understanding of the link between the meteorological (or synoptical parameters and the observational conditions thanks to the application of the theories of electromagnetic waves propagation in turbulent medias: what we actually call astroclimatology. At the present the site campaigns are evolved and are performed using the classical scheme of optical seeing properties, meteorological parameters, sky transparency, sky darkness and cloudiness. New concept are added and are related to the geophysical properties such as seismicity, microseismicity, local variability of the climate, atmospheric conditions related to the ground optical turbulence and ground wind regimes, aerosol presence, use of satellite data. The purpose of this project is to provide reliable methods to analyze the atmospheric properties that affect ground-based optical astronomical observations and to correlate them with the main atmospheric parameters generating turbulence and affecting the photometric accuracy. The first part of the research concerns the analysis and interpretation of longand short-time scale meteorological data at two of the most important astronomical sites located in very different environments: the Paranal Observatory in the Atacama Desert (Chile), and the Observatorio del Roque de Los Muchachos(ORM) located in La Palma (Canary Islands, Spain). The optical properties of airborne dust at ORM have been investigated collecting outdoor data using a ground-based dust monitor. Because of its dryness, Paranal is a suitable observatory for near-IR observations, thus the extinction properties in the spectral range 1.00-2.30 um have been investigated using an empirical method. Furthermore, this PhD research has been developed using several turbulence profilers in the selection of the site for the European Extremely Large Telescope(E-ELT). During the campaigns the properties of the turbulence at different heights at Paranal and in the sites located in northern Chile and Argentina have been studied. This given the possibility to characterize the surface layer turbulence at Paranal and its connection with local meteorological conditions.

Development and optimization of graphic user interfaces (GUIs) for infrared spectrometers at the Telescopio Nazionale Galileo

This Phd thesis was entirely developed at the Telescopio Nazionale Galileo (TNG, Roque de los Muchachos, La Palma Canary Islands) with the aim of designing, developing and implementing a new Graphical User Interface (GUI) for the Near Infrared Camera Spectrometer (NICS) installed on the Nasmyth A of the telescope. The idea of a new GUI for NICS has risen for optimizing the astronomers work through a set of powerful tools not present in the existing GUI, such as the possibility to move automatically, an object on the slit or do a very preliminary images analysis and spectra extraction. The new GUI also provides a wide and versatile image display, an automatic procedure to find out the astronomical objects and a facility for the automatic image crosstalk correction. In order to test the overall correct functioning of the new GUI for NICS, and providing some information on the atmospheric extinction at the TNG site, two telluric standard stars have been spectroscopically observed within some engineering time, namely Hip031303 and Hip031567. The used NICS set-up is as follows: Large Field (0.25'' /pixel) mode, 0.5'' slit and spectral dispersion through the AMICI prism (R~100), and the higher resolution (R~1000) JH and HK grisms.

Dalle feste di nozze alle orchestre di stato: Maria Lătărețu e l'invenzione della muzică populară

Le musiche “popolaresche” urbane, in genere trascurate nella letteratura etnomusicologica, sono state quasi completamente ignorate nel caso della Romania. Il presente studio si propone di colmare almeno in parte questa lacuna, indagando questo fenomeno musicale nella Bucarest degli anni Trenta e Quaranta del Novecento. Le musiche esaminate sono tuttavia inserite entro una cornice storica più ampia, che data a partire dalla fine del XVIII secolo, e messe in relazione con alcune produzioni di origine rurale che con queste hanno uno stretto rapporto. Il caso di Maria Lătărețu (1911-1972) si è rivelato particolarmente fecondo in questo senso, dal momento che la cantante apparteneva ad entrambi i versanti musicali, rurale e urbano, e nepadroneggiava con disinvoltura i rispettivi repertori. Dopo il suo trasferimento nella capitale, negli anni Trenta, è diventata una delle figure di maggior spicco di quel fenomeno noto come muzică populară (creazione musicale eminentemente urbana e borghese con radici però nel mondo delle musiche rurali). L’analisi del repertorio (o, per meglio dire, dei due repertori) della Lătărețu, anche nel confronto con repertori limitrofi, ha permesso di comprendere più da vicino alcuni dei meccanismi musicali alla base di questa creazione. Un genere musicale che non nasce dal nulla nel dopo-guerra, ma piuttosto continua una tradizione di musica urbana, caratterizzata in senso locale, ma influenzata dal modello della canzone europea occidentale, che data almeno dagli inizi del Novecento. Attraverso procedimenti in parte già collaudati da compositori colti che sin dal XIX secolo, in Romania come altrove, si erano cimentati con la creazione di melodie in stile popolare o nell’armonizzazione di musiche di provenienza contadina, le melodie rurali nel bagaglio della cantante venivano trasformate in qualcosa di inedito. Una trasformazione che, come viene dimostrato efficacemente nell’ultimo capitolo, non investe solo il livello superficiale, ma coinvolge in modo profondo la sintassi musicale.