Fasting the two consecutive months by sighting or by the calendar

Question:
He says: Honorable Shaykh, may Allah grant you success. If a person owes an expiation and fasts two consecutive months, does he fast the two months based on the calendar, or based on the sighting? And if he is unable to determine the new moon, what should he do?

Answer:
He fasts by count, sixty days. Because he does not see the new moon. If he sees the new moon, he acts according to its sighting. But if he does not see the new moon, he falls under the saying of the Messenger (peace and blessings be upon him) Complete the number of days of the month. So he completes the number of days of the month as thirty, and fasts sixty days. As for the calendar, it is not relied upon for fasting; it is not relied upon. The saying of the Messenger (peace and blessings be upon him) is: .