The dogon in africa were given four calendars by visitors from sirius b : solar , lunar , venu sian , and civil 非洲多贡人被来自天狼星的来访者授予了四种历法：太阳，月亮，天狼星和金星。
2.
The dogon calendar identified the 12 or 13th century as the date of last visit ; the mayan calendar identified july 11 , 1991 , as an upcoming date of visit 多贡人历法把12或13世纪看作是最后一次到访的日期，玛雅历法是鉴定为1991年7月11日，是一个即将来临的来访日。
