The equinox is the time of the year when the sun is directly above the equator. It means that the sun goes straight up and straight down at the time of sunrise and sunset. It also results in the length of day and night being roughly the same. It happens twice a year, usually around March 20th and September 22nd. In Thailand, it happened during the early hours of this morning. My house is on the East-West axis with the front door facing south. From now until March, the sun leans more towards the south and so this means that the small garden at the back of my house won’t receive any direct sunlight. The point where it does an about turn and heads back towards the north is called the Solstice and this usually occurs around December 21st. This is our shortest day of the year. March 20th is the second equinox, when the sun is again above the equator, and the sun then starts moving towards the north. From this point on, the back of my house starts to receive the sun again. Our longest day of the year is around the second solstice on June 20th. This is when the sun stops its northward march and starts returning to be straight above the equator again in September.
Really, as we are quite close to the equator, our length of day doesn’t vary that much throughout the year. In mid-December, we have 11 hours and 18 minutes of daylight. In mid-June, the length of our day is 12 hours and 56 minutes. So, the difference is only about 90 minutes. During December, I always do a project with my Thai students. They have to find the times of the sunrise and sunset in three different locations. London, England in the Northern Hemisphere. Bangkok, Thailand near the equator. And Sydney, Australia in the Southern Hemisphere. From this they need to calculate the length of day. They then repeat this for June for the same locations. The students are not expecting anything dramatic. In December, the sun rises at 6.37 a.m. and in June it goes up at 5.51 a.m. That isn’t a lot of difference. It probably means that they will still go to school during the daylight. In December in Thailand, the sun sets at 5.55 p.m. In June the sun goes down at 6.48 p.m. So, again, this difference doesn’t really affect the students. They are already back home. Probably inside the house, watching TV or playing video games. So, they probably wouldn’t notice the difference.
I think all of this will only affect people like the monks, who will be going out on their alms round when it is still dark during December. If I am going to take pictures of an alms round, then the best time of the year to do this is obviously around June. At this time of year, it is usually light enough to take pictures by 6.30 a.m. I remember sitting at a temple once at 6 a.m. waiting for the monks to leave. This was about late July. It was still dark and I could only see twenty metres or so. By the time they left at 6.10 a.m. it was just light enough to take pictures. However, any movement resulted in a blur. Then, suddenly at 6.20 a.m., it was light enough to take action pictures as normal. Which was just as well as the monks were keeping a good pace. I guess this is the advantage of living near the equator as it is almost like a light being turned on. In December I wouldn’t be able to get pictures until the end of their alms round.
The students do their research on the Internet. Before they start, I always ask them to guess the time of sunrise and sunset for these different locations. During the project, I teach them that in December, the UK, in the Northern hemisphere is having winter and hence their days are short and nights long. Places like Australia, in the Southern hemisphere, are the opposite and are enjoying the summer with long days and short nights. Even though this is a big clue, there are still completely bowled over when they discover the real times. They find it difficult to comprehend that although they enjoy an average of 12 hours of daylight throughout the year, that people in the UK don’t get much more than seven hours of daylight in December. I told them that when I went to school in the winter, it was dark when I left home and dark again when I got home. Their jaws just dropped when they saw that sunset was at 3.54 p.m. I guess they felt sorry for us, but then they saw that in June, we could play outside in the garden until quite late in the evening without lights.
Two good websites for calculating times of sunsent and sunrise are www.sunrisesunset.com and www.timeanddate.com. If you are planning a holiday to Thailand, then you don’t really need to know more than that it is usually light by 6.30 a.m. and dark by 7 p.m. throughout the whole year. It may be boring compared to some countries in Northern Europe, but at least we are more predictable. I guess the biggest advantage is that we don’t need to worry about daylight saving and having to move our clocks twice a year. I tried to explain this concept to my Primary 6 students last month and I don’t think they really understood. After all, I haven’t done this “length of day” project with them yet. At the moment, they still think that sunrise and sunset around the world happens at exactly the same time.
Related blog: Understanding… The Thai Lunar Calendar