  This writeup is an introduction to neutrino astronomy, addressed to
astronomers and written by astroparticle physicists. While the focus is on
achievements and goals in neutrino astronomy, rather than on the aspects
connected to particle physics, we will introduce the particle physics concepts
needed to appreciate those aspects that depend on the peculiarity of the
neutrinos. The detailed layout is as follows: In Sect.~1, we introduce the
neutrinos, examine their interactions, and present neutrino detectors and
telescopes. In Sect.~2, we discuss solar neutrinos, that have been detected and
are matter of intense (theoretical and experimental) studies. In Sect.~3, we
focus on supernova neutrinos, that inform us on a very dramatic astrophysical
event and can tell us a lot on the phenomenon of gravitational collapse. In
Sect.~4, we discuss the highest energy neutrinos, a very recent and lively
research field. In Sect.~5, we review the phenomenon of neutrino oscillations
and assess its relevance for neutrino astronomy. Finally, we offer a brief
overall assessment and a summary in Sect.~6. The material is selected - i.e.,
not all achievements are reviewed - and furthermore it is kept to an
introductory level, but efforts are made to highlight current research issues.
In order to help the beginner, we prefer to limit the list of references,
opting whenever possible for review works and books.
