The team spent two years getting the telescope ready for the International Year of Astronomy, which marks the 400th anniversary of Galileo's discoveries, including the then-heretical conclusion that the Earth revolved around the sun, not vice versa.
The team from Florence's Museum of the History of Science and the national institutes of applied optics, nuclear physics and astrophysics worked with the Experimental Glass Station in Murano to produce the exact composition of the glass Galileo used for the lens of the telescope he created and described in his 1610 treatise Sidereus Nuncius ("Starry Messenger").
''It was immediately clear that the telescope is not at all easy to use,'' said Giorgio Strano of the Museum of the History of Science.
Francesco Palla of the National Institute of Astrophysics' Arcetri Observatory said the team has ''almost finished'' duplicating Galileo's celestial observations.
The images observed with the replica telescope will be digitalized and published online by the end of the year.
Galileo (1564-1642) was one of the few people of his day with a lens powerful enough to observe the sky. His conclusions led to his conviction for heresy and he spent the last nine years of his life under house arrest.