Should one follow the prayer times adopted by the mosque (12 degrees) or the times provided by websites (18 or 17 degrees), especially given the lack of justification for using 12 degrees?

The legally binding method for determining prayer times relies on the cosmic signs that the Sharia (definition) has established as indicators for these times. These signs are valid for all times and places. Other calendars and astronomical calculations are merely tools to facilitate the knowledge of these regulations. If it is possible to ascertain the times according to the Sharia regulations, then it is obligatory to act upon them. It is permissible to accept the word of a trustworthy, upright person who knows the time, such as an imam or a muezzin.

If the mosque has an upright imam or muezzin who is knowledgeable about prayer times, then follow him. However, if he makes the call to prayer based on personal ijtihad (definition) (independent reasoning) and not on knowledge of the time, it is not permissible for someone capable of ijtihad to follow him. As for someone incapable of ijtihad, they may follow him.

The venerable Al-Ramli stated in "Nihayat al-Muhtaj": "Whoever is capable of ijtihad should not follow a mujtahid, because a mujtahid does not follow another mujtahid. Yes, a person blind in sight and insight may follow a trustworthy, knowledgeable person who can see. And the adhan (definition) of an upright person knowledgeable of the prayer times in clear weather is like reporting from knowledge."