It results from an apparent irregular movement of the Sun caused by a combination of the obliquity of the Earth's rotation axis and the eccentricity of its orbit. The equation of time is the difference between time as read from a sundial and a clock. These two measures are the equation of time and the declination of the Sun. There are two astronomical measures that are essential for computing prayer times. The next section provides information on how to calculate the above times mathematically for any location if the coordinates of the location are known. The mean time from sunset to sunrise (or from sunset to Fajr, in some schools of thought). The time at which darkness falls and there is no scattered light in the sky. The time at which the Sun disappears below the horizon. The time when the length of any object's shadow reaches a factor (usually 1 or 2) of the length of the object itself plus the length of that object's shadow at noon. When the Sun begins to decline after reaching its highest point in the sky. The time at which the first part of the Sun appears above the horizon. These times are defined in the following table: Perhaps more familiar to us as Yule, the 12-day festival centred around the solstice has given birth to many of our most familiar Christmas traditions including the Christmas tree, the Yule log and the Christmas wreath.To determine the exact time period for each prayer (and also for fasting), we need to determine nine points of time per a day. Solstice and ChristmasĪmongst the many festivals that centre around the solstices and equinoxes, the Scandinavian festival of Jul has some rituals that are probably more familiar than you think. True solar noon, the point at which the Sun reaches its highest point in the sky, occurs around 10 minutes earlier than when our clocks strike 1200, and it is this discrepancy that means the sunset also arrives a little later on the solstice. Logically you'd expect the earliest sunset to fall on the shortest day, but the earliest sunset actually occurs a few days earlier in the calendar and it's all to do with our clocks not quite mirroring the Earth's orbit. The summer solstice in June is just short of 16 hours and 38 minutes long, while on the day of the winter solstice the length of the day is a mere 7 hours and 50 minutes. You're probably aware that the day of the winter solstice marks the shortest day of the year, but did you know that its almost nine hours shorter than the longest day of the year? Winter beginsĪs well as marking the shortest day of the year, the winter solstice marks the first day of winter in the astronomical calendar, whilst in the meteorological calendar, we are already three weeks into winter. Owing to the Sun appearing to 'standstill' in the sky when it reaches the Tropic of Capricorn, the word solstitium was used which in turn is composed of the words sol (meaning 'sun') and sistere (meaning to 'standstill'). Like many other astronomical terms, the word solstice comes from Latin. The solstice marks the point at which the Sun is exactly overhead the Tropic of Capricorn, which this year will happen on Sunday, 22 December at 04:19 GMT. While many focus on the winter solstice as a day in the calendar, what we are actually talking about is a very specific moment which is over almost as soon as it has begun.
0 Comments
Leave a Reply. |