戴盆望天　

◎ 戴盆望天 dàipén-wàngtiān

[work blindly;try to discover the mystery of the sky by covering the head with a tub] 头戴盆子而想看天上。比喻行动跟目的相反,愿望无法实现(语出司马迁《报任安书》)

戴盆望天,不见星辰。——《易林·小过之蛊》