Prayer: Determining the Direction of Qibla
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 769
Someone who wants to perform prayers must make efforts to find out the direction of qibla to the extent that he attains certainty about its direction, or that which comes under the rule (ḥukm) of certainty, such as the testimony of two dutiful people if their testimony is based on sensory perception and suchlike. If he cannot [find out its direction to this extent], he must act according to what he supposes to be the direction of qibla based on the position of the miḥrāb[1] of a mosque, or the graves of believers, or by some other way. Even if he bases his supposition (ẓann) on the words of an immoral person or a disbeliever who knows the direction of qibla by employing scientific principles, it is sufficient.