Naked eye observations for morning twilight at different sites in Egypt

Twilight observation by the naked eye of the dawn sincere at Hail and other areas in Saudi Arabia

“…In addition to the naked eye observations which recorded on four locations in Egypt; Matrouh, Bahria, Kottamia and Aswan and all had the same results. In 2014, Hassan et al (2014aHassan et al ( , 2014b concluded that there is a good agreement between the photoelectric measurements and the naked eye observations of the beginning of morning twilight (true dawn) in four locations in Egypt (Issa and Hassan, 2008a, 2008b, 2008cIssa et al, 2009Issa et al, , 2011Hassan et al, 2013Hassan et al, , 2014aHassan et al, , 2014bHassan and Abdel Hadi, 2015). All the above mentioned results are summarized in Table 5.…”

Predicting the accurate period of true dawn using a third-degree polynomial model

“…All values of the polynomial parameters p 0 , p 1 , p 2 and p 3 completed with the R 2 value for the reliable data of keeping 18-day observations can be seen in Table 2. It is interesting because of the naked eye observations for the morning twilight have been reported to have an average value of −14.7°for the "dep" angle of the horizon at different sites in Egypt (Hassan et al 2014) and that of −14.7°for that at Tubruq of Libya through 4 years observations (Hassan and Abdel-Hadi 2015).…”

“…The visualisation literacy of sky brightness data recorded at Teluk Kemang of Negeri Sembilan, Pantai Cahaya Bulan of Kelantan and Kuala Terengganu of Terengganu in Malaysia starting from half an hour before the beginning of dawn prayer until the sunrise to extract information from the data visualisation graphs has been concluded that the beginning of true dawn is at a depression angle of −20°below the east horizon (Nor and Zainuddin 2012). Even though a comprehensive approach to the numerical modelling of verifying the presence of dawn twilight has been proposed using the data of the naked-eye observations (Garstang 2000;Hassan et al 2014;Hassan and Abdel-Hadi 2015), the use of digital data collected from monitoring the night sky brightness to determine the beginning of dawn twilight using thirddegree polynomial model is still not fully understood. The aim of this study was to make a measurable improvement to be used in the verification of the presence of twilight zone in a region for specifically determining the exact "dep" position of beginning the obligatory dawn prayer.…”

Image Processing Application to Know the Dawn of Shadiq Using Matlab Software

“…Meanwhile, Saksono found that the altitude of the sun against the horizon (dip) used by the Ministry of Religion to determine early dawn should be corrected immediately. The results of his research using the Sky Quality Meter (SQM) sensor state that the dawn of shadiq appears when the sun's height is - 13 The word "white thread" is a figurative word for the dawn on the eastern horizon. Because when the dawn of Shadiq comes, the first visible light extends on the eastern horizon like a white thread from north to south.…”