Negretti & Zambra Telescope

[DRT]

I was in Portugal last week and stumbled across this fine looking beast at a friend's house...

 

From memory it was around 4" aperture and about 1.2m in length when the focus tube was extended.

A quick google reveals that the manufacturer was a highly respected instrument maker in the second half of the 19th century and existed until the 1990s.

Does anyone know when this style of scope is likely to have been made and whether or not it has any significant value?

[Peter Drew]

Its ages since I last saw a N&Z refractor, mostly smaller than the one shown. I've no idea as to the value but would expect one to be on a par with other famous makes of the period.