Lunar calendar or crescent moons and others employing detailed calculations. Since each lunation is approximately days (29 days, 12 hours, 44 minutes, 3 seconds, or days), it is common for the months of a lunar calendar to alternate between 29 and 30 days. Since the period of twelve such lunations, a lunar year, is only 354 days, 8 hours, 48 minutes, 34 seconds ( days), purely lunar calendars lose around 11 days per year relative to the Gregorian calendar. In purely lunar calendars like the Islamic calendar, the lack of intercalation causes the lunar months to cycle through all the seasons of
Dundrod Circuit the 2017 Ulster Grand Prix. The race record for the Dundrod Circuit is an average speed of set by Bruce Anstey during the 2017 Ulster Grand Prix. The lap record for the RAC Tourist Trophy on the Dundrod Circuit is 4 minutes and 42 seconds at an average speed of 94.67 mph (152.3582 km/h) held by Mike Hawthorn driving a Jaguar D-Type set during the 1955 RAC Tourist Trophy. The race record for the RAC Tourist Trophy on the Dundrod Circuit is 7 hours, 3 minutes and 12 seconds an average speed of 88.32 mph (142.139 km) for 84 laps