1421 Esperanto in the outer asteroid belt at a distance of 2.8–3.4 AU once every 5 years and 5 months (1,983 days; semi-major axis of 3.09 AU). Its orbit has an eccentricity of 0.08 and an inclination of 10° with respect to the ecliptic. The body's observation arc begins with its first observation as at Heidelberg Observatory in October 1906, almost 30 years prior to its official discovery observation at Turku. This minor planet was named by the discoverer after the artificial language, Esperanto, which was created by inventor and writer, Ludwik Lejzer Zamenhof (1859–1917), who used the pseudonym "Doktoro Esperanto". The
Mark Zamenhof usage of Polish national dresses. The police in the exploration suspected, that that anonymous letter was written by Zamenhof, because he led that time a concurs school for girls and already sooner had written various denunciation letters. Zamenhof indeed that time shared the possession of the school for Jewish girls. In 1866 in it were 63 pupils. Several Polish biographers write that Mark Zamenhof was teacher of the Bialystok high school (actual school). If he instructed in that high school, probably that was only for a short episode, that probably happened after the "January Uprising" (so in 1864). Prospective hire