Is Using Telescopes to Sight the Crescent Moon Permissible?
Is sighting the crescent moon with telescopes allowed in Islam? Learn the Islamic ruling on using modern optical tools for moon sighting (hilal).
Portal Islam 
This article was first published in Indonesian. Baca versi Bahasa Indonesia →
Question
Must the crescent moon (hilal) be sighted with the naked eye, or is it permissible to use telescopes and modern equipment?
Answer
All praise is due to Allah. Textual evidence in Islamic law indicates that a person is not required to sight the hilal using optical aids such as telescopes or modern technological instruments. Direct observation with the naked eye is completely sufficient.
However, if someone sights the crescent moon using these instruments after sunset, is certain of their sighting, and is an upright ('adl) Muslim, their sighting is valid and accepted. This is still considered visual sighting (ru'yah), rather than purely astronomical calculation (hisab).
