If someone used a compass to find the qibla and later on he found out that the direction was wrong, should he repeat his Salah? Is the use of a compass equivalent to taharri?
بِسْمِ اللهِ الرَّحْمنِ الرَّحِيْم
In the name of Allah, the Most Gracious, the Most Merciful
If a person prays his salah after doing some research as to which direction is the qibla, thereafter comes to know that the direction was incorrect, his prayer would be valid. There would be no need to repeat that prayer. The use of a compass will be equivalent to taharri.
Only Allah knows best
Written by Maulana Irfan Ali
Checked and approved by Mufti Mohammed Tosir Miah
Darul Ifta Birmingham
 Kitabul Nawazil vol 3 page 437 Darul Ishat