Ora-01846: not a valid day of the week

Ora-01846: not a valid day of the week

select to_date('Mon Jan 21 13:25:47 2008', 'dy mon dd hh24:mi:ss yyyy') from dual
Ora-01846: not a valid day of the week
出现的是中文的字符日期，如下：星期五 12月 19 13:53:15 2008
 是字符集的问题，解决：
alter session set nls_date_language = 'American'