In 2014, Larry Heyda released the Heydascope Viewer. I understand that Larry is no longer producing the viewers. Two different different configurations were available:
The Heydascope Ultimate — a full-package focusing viewer complete with backlight
The Heydascope Scholar — a lower priced fixed focus viewer with optional back light add-on
Both types of viewers feature massive 2″ diameter achromatic lenses with anti-reflection coating. The focal length is 75 mm, making it perfect for ortho viewing. Larry states that the interocular spacing is 65.66 mm. Larry worked with an optics company to produce the lenses specifically for this viewer and the lenses are of high quality. The standard configuration accepts the 3D World plastic mounts, however adapters for other formats can be custom-ordered. Larry is a professional sculptor and the viewer enclosure is made of hand-cast resin. The light is activated by a momentary button switch on the bottom that is pressed with one’s thumb. It is placed quite ergonomically, however it always requires an explanation when handing the viewer to someone who hasn’t used it. The viewer is rather large and heavy, around 1 kg.
