American Optical Microscopes (AO) was a renowned and innovative microscope manufacturer. Its early rots were in the Spencer Lens Company, which it acquired in 1935. It was later acquired by Reichert Technologies, which in turn became a part of Leica.
American Optical or Spencer microscopes were very popular from the 1940s through the 1980s, when the company was acquired. Many models from that have a robust build quality and long working lives. As a result, the US used market has many AO models available at characteristically low prices for hobbyists who enjoy refurbishing and repairing microscopes.
- Series 2/4 using 160mm finite optics
- Series 10/20 using infinity corrected optics and a 34mm barrel length
- Series 110/120using infinity corrected optics and a 34mm barrel length
- Series 410/420 (MicroStar IV), often marketed under the name Reichert, Cambridge, or Leica, and using infinity corrected optics with a 45mm barrel length
- Cycloptic The most popular early common main objective stereo microscope