TV-85 - BirdForum Opus

Rather large - 4 kg (8.5 lbs. or so). Not waterproof. Uses astronomy eyepieces (1.25 inch or 2 inch), of which there is a myriad of cheap or expensive, single power or zooms available. A 1.25 inch, 60 degree Tele Vue diagonal turns it into an angled scope. Images are reversed left to right unless you purchase a 45-degree erecting diagonal (prism), or the Tele Vue straight through porro prism. Regular zoom eyepieces (8 to 24mm focal length) produce 25x to 75x. A barlow (doubler), in front of the zoom gives 50x to 150x. Images hold up well in still air at 150x. Requires a substantial tripod (I use a surveyors). Content and images originally posted by rhop