<prompt> Translate the following text to EnglishMnara wa angani uliongezwa katika miaka ya 1920, lakini anga lenye moshi na mvuke wa treni juu ya jiji wakati huo ulifanya kuwa mahali pasipofaa kwa kutazama nyota.  <response>: An additional observatory was added in the 1820s, but the smoky skies and train steam over the city at that time made it an unsuitable location for watching the stars. 