New crescent on Friday

Based on the astronomical calculations, the Qatar Calendar House (QCH) has announced that the new crescent of the Hijric month "Rabia II 1440 H" will be born on Friday 29 Rabia I 1440 H (December 7, 2018 ) at 10:21am Doha local time (07:21am Universal Time).
The duration of the new crescent of "Rabia II 1440 H" will be 6 hours and 22 minutes over Qatar sky on Friday, said Dr. Beshir Marzouk, astronomy expert at QCH.
Dr. Marzouk said the time of sighting of new crescent over Qatar sky on Friday will be 5:01pm and the sunset will be at 4:44pm, which means the new crescent will be seen 17 minutes after sunset over Doha sky. The time of sighting of new crescent after sunset time over sky of two holy mosques (Makah & Medina) and over all Gulf countries will be varied between 16 to 18 minutes. The duration between the sighting of the new crescent and sunset time will be more over countries on west side.
Dr. Marzouk added that it will be possible to observe the new crescent of "Rabia II 1440 H" from most of Arabic and Islamic countries with astronomical telescopes and from places without environment pollutions on the evening of Friday..
Consequently & according to astronomical calculations, the first of Hijric month "Rabia II 1440 H"  will be start on Saturday, December 8, 2018, while the Hijric month "Rabia I 1440H" will be ending on Friday.
The Hijric calendar calculations are based on Moon's motion on its orbit around the Earth, while the Gregorian calendar is based on Earth's motion on its orbit around the Sun.