In his book "The Real Fajr (Dawn) - Between the Quranic Determination and Linguistic Usage" (with the preface written by the two great scholars Sheikh Salih Al-Fawzan and Sheikh Abdul Aziz Al-Sheikh), the author Ustadh Doctor Ibrahim Bin Muhammed Al-Sabeheeh wrote:
"If a person or an imam comes and says, 'People are praying too early!' and another person says to them, 'Don't pray!' and another group says, 'Repeat the prayer or it is invalid!', then this is sowing doubts in one of the acts of worship. This is not allowed except based on a fatwa (Islamic legal opinion) by the highest authority of Islamic legislation in this country. This is because this matter is related to the most important act of worship, and no person is allowed to interfere in these matters based on their own opinion. People are not qualified to judge astronomical and computational issues, as well as those related to prayer times and their calculation, whether it is about sighting or calculation. Accordingly, this matter should be left to the specialists, so that the matter remains in its original form and it is not allowed to spread doubts about it."
Sheikh Uthaimin on fasting times during Ramadan حكم تأخير أذان الفجر ربع ساعة عن التقويم..
Schaych Abdul-Aziz Aal Asch-Schaych zu MWL
Schaych Abdurrahman Muhidin zu MWL
Sheikh Arafat: When does Ishaa end?
Sheikh Ubayd: Das Zusammenfassen von Maghreb und Ishaa
Regarding the spreading of doubts about prayer times (MWL)
Why are the fasting times of the Muslim World League (MWL) correct?
Warum gibt es unterschiedliche Zeiten bei Maghrib?
Warum sind die Fastenzeiten nach der 90-Minuten-Regel nicht richtig?
Calculation based on sightings or solely based on sightings?
Falsche MWL-Zeiten in anderen Internetseiten und Apps?
Warum sind die Diyanet Fastenzeiten nicht immer richtig?