The ruling on relying on a compass to determine the qiblah

The listener Muhammad Ahmad from Egypt, Sharqia Governorate, sent a message containing an issue. He says: A month ago, one of the brothers visited our town, and when he stood to pray, he said: This mosque is not facing the qiblah. The people were stunned, and when he brought out the compass, we found that the qiblah the mosque was facing was indeed incorrect. It is known that this mosque is very old, about forty years old. Some people said that this man is a liar, even though he proved it to us with evidence. So, a group of people prayed facing the new qiblah as he said, and another group from the congregation prayed facing the old direction. What do you advise the people to do? May Allah reward you with good.
Answer: We advise everyone to return to the people of knowledge, the people of knowledge in the town from the supporters of the Sunnah, and the scholars known for the Sunnah, uprightness, knowledge, and virtue, so that they can look into the qiblah, together with the responsible officials from the endowments (waqf) who are with them, so that they can cooperate in rectifying the qiblah. If the deviation is slight, it is excused. If the deviation is slight, it is excused. But if the deviation is significant, it is corrected. One should not look to those who objected to the mosque without proof, but rather return to the people of knowledge and the officials in the endowments. So, if the people of knowledge determine that the deviation is significant, the mosque is corrected. And if the deviation is slight, it is excused. This is based on the saying of the Prophet (peace and blessings be upon him): meaning: the direction is sufficient, even if there is a deviation. Likewise, what is between the south and the north is the qiblah for those who are in the east and the west. And for those who are in the south or the north, what is between the east and the west is the qiblah, like the people of Madinah. So, the result is that the direction is sufficient. So, for the one in the west, what is between the south and the north is sufficient. And for the one in the east, likewise, what is between the south and the north is sufficient. As for the one in the south or the north, his qiblah is the direction between the east and the west, as the Prophet (peace and blessings be upon him) said in the hadith of Abu Hurayrah.
The point is that the direction is sufficient, and a slight deviation is forgiven. And if someone comes to object, they return to the people of knowledge known for uprightness, along with ... the officials in the endowments, so that they can look into the matter and strive to correct the qiblah if there is a significant deviation. Yes.
The presenter: May Allah reward you with good. If it becomes clear that the mosque was indeed not facing the qiblah, they ask about the ruling on the previous prayers in that mosque?
The Shaykh: ... They were making ijtihad (independent legal reasoning), and it does not harm them. The previous prayers do not harm them; they are valid, there is nothing wrong with them; because they prayed making ijtihad facing the qiblah that was designated for them. The discussion is about the future: they look and pray as they are until the people of knowledge known in the town, along with the officials in the endowments, verify for them, so that it becomes easy, meaning the thing that gives peace of mind from the perspective of the people of knowledge; because they are the ones responsible for these issues. The people of knowledge are the ones responsible. Yes.
The presenter: May Allah reward you with good. What is the ruling on relying on a compass, Your Eminence?
The Shaykh: The compass is a good and useful device, but it must be handled by the people of knowledge and people of insight. Yes.
The presenter: May Allah reward you with good.