The Antique Partnership has dated this piece to the Regency era.
It is complete with its objective lens cap (often lost) and has a viewing lens shutter. There are of course imperfections due to time and useage but it functions well and displays admirably on its later mahogany stand. Also included is a leather carrying cover which is in good order but dates from the 14/18 war .

J.cetti and Co commenced under Joseph Cetti in 1802 in Long Lane Smithfied and thereafter 54 Red Lion street from 1803-15 and 25 Red Lion street 1816-39 with his Son John.
74.5 cm long fully extended 24.7 Closed
Diameter 5 cm the object lens being about 4cm.
The Antique Partnership has dated this piece to the Regency era.
You can view the stock and full dealer information on the The Antique Partnership Profile Page