Alexan­der Beck­ers was a Ger­man born daguerreo­typ­ist and inven­tor and man­u­fac­tur­er of stere­o­scopes. He designed a mul­ti­view stere­o­scope based on a rotat­ing belt mech­a­nism. This design served as a mod­el for the chain-based stere­o­scope, a type that would con­tin­ue to be man­u­fac­tured until the 1930s.
The first record­ed pres­ence of Beck­ers in the Unit­ed States is a reg­is­tra­tion in Philadel­phia in 1836. He learned the daguerreo­type process from Fred­er­ick Lan­gen­heim and was work­ing for the Lan­gen­heim broth­ers’ com­pa­ny in 1843.
In 1857 he patent­ed his first design for a chain-based stere­o­scope. One year lat­er he sold his daguerreo­type busi­ness and sub­se­quent­ly focused on the design and man­u­fac­ture of stere­o­scopes. From 1869 to 1870 his com­pa­ny was locat­ed at 560 Broad­way in New York.
(from: Com­pendi­um of Stereoscopes)