The astronomical reports about the timing of the eclipse must not be taken as the basis for offering Salat-ul-Kusuf. Some people of knowledge, including Shaykh-ul-Islam Ibn Taymiyyah and his knowledgeable disciple Ibn Al-Qayyim, may Allah be merciful with both of them, supported this view saying that the astronomers may sometimes be wrong and then these reports are not reliable and people should not offer Salat-ul-Kusuf depending on them. Rather, they have to offer the Salah upon seeing the eclipse when it is happening.
The publications of the astronomers’ reports about the timing of eclipse should be banned by the Ministry of Information lest some people should be deceived by them. These publications may make people feel less fear upon seeing the eclipse. Allah (Exalted be He) has made them to be frightening and hence, people remember, fear, invoke Allah, and treat their slaves well. May Allah grant us success!
Source : Browse by Volume Number > Volume 13 > Completion of the Book of Salah (Prayer) > Salat-ul-Kusuf > the manner of Salat Al-Kusuf