1,720,968 research outputs found
Padre Secchi e la spettroscopia
No full textViene analizzato il contributo di Padre Secchi alla spettroscopia stellare e solare, particolarmente in relazione allo sviluppo storico-scientifico dell'astrofisica e alla successiva classificazione spettrale di Harvard
Measuring stellar temperatures : an astrophysical laboratory for undergraduate students
No full textWhile astrophysics is a fascinating subject, it hardly lends itself to laboratory experiences accessible to undergraduate students. In this paper we describe is presented a feasible astrophysical laboratory experience, in which students are guided to take several stellar spectra, using a telescope, a spectrograph and a CCD camera, and perform a full data analysis using the equivalent widths method on some spectral lines. This allows them to derive stellar temperatures after a suitable calibration and fitting procedure. On average the estimated stars temperatures agree with known results within an error margin of 5 to 10% for cold stars, and 20 to 25% for hot stars
La ricerca di caratteristiche sensibili alla luminosità negli spettri stellari fino agli anni Venti del Novecento
No full textI contributi di studiosi italiani all'astronomia gravitazionale, astronomia osservativa e all'astronomia descrittiva alla fine del XIX secolo
No full textIl laboratorio storico in un insegnamento universitario : l'esperienza del corso di laboratorio di astronomia e astrofisica
No full textMisurare crateri e montagne lunari : progetto, osservazioni, misure, monitoraggio, focus group. Il progetto LERU - Kids University 2005 all'Università degli Studi di Milano
No full textIn the context of the European Project Kids University promoted by the League of European Research Universities (LERU), the Universita degli Studi in Milan has proposed to 60 ten-to-twelve-year-old students to carry out observations of the Moon with a telescope in order to measure the height of its mountains and the diameter of its craters. The students have thus made a real observational activity and they have been requested to connect the mathematical and geometrical concepts they have learned at school to the context of physical measures. The initiative has been carried out at the Brera Astronomical Museum and its historical meaning has been emphasized: in fact lunar mountains and craters were firstly observed in the 1609 by Galileo Galilei who suggested a method, for their measurements, which has been partially used by the students. The students who have participated in the initiative presented it to kids of their own age in a very crowded meeting. Further, some students of the school "Sabin" in Segrate (Milan), with the help of their teachers, have made a video documentary about the experience. Finally, a focus group has been carried out to evaluate the impact of the initiative upon the participants
Stellar temeratures by Wien's law : not so simple
No full textA star’s surface temperature is among the most important features that can be deduced from its
light. We have made measurements to see how reliably we could determine the surface
temperatures of some A to K stars using Wien’s Displacement Law. We took spectra, corrected
them for atmospheric extinction and instrumental response, found the wavelengths of their
intensity maxima, and then from Wien’s law found the surface temperatures of the observed stars.
For F to early K stars, our results agree with temperatures determined in other ways. For A and
later K stars, the agreement is poor because the spectra are appreciably different from ideal
blackbody spectra and because our equipment responds poorly to the deep red and blue
wavelengths where the spectra of these stars have their peak intensities. This paper points out
several interesting concepts in and outside the astrophysical domain that can be instructive for
undergraduate students
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