BOROSCOPE SHEATH

The invention concerns a boroscope sheath (20) for providing a boroscope with temperature protection during a boroscope inspection of a machine such as a gas turbine or a steam turbine, the boroscope sheath comprising an elongate tube extending from a front end (54) of the boroscope sheath to a back end (34) of the boroscope sheath, the elongate tube comprising a wall (32) extending from the front end to the back end and extending around a central bore (50), the central bore being configured and arranged to allow removable insertion of a boroscope (55) into the central bore, one or more cooling channels (40, 41, 42, 44) extending in the wall, and means for holding the boroscope sheath in a first position relative to the machine when the machine is in use and for moving the boroscope sheath to a second position relative to machine for inspection, and in which at least part of the boroscope sheath is configured and arranged to remain in the machine during use of the machine. Methods of cooling a boroscope sheath, inspecting a part of a machine and of manufacturing a boroscope sheath are also described.