Presentation on theme: "Heavenly Mathematics & Cultural Astronomy Helmer Aslaksen Department of Mathematics National University of Singapore"— Presentation transcript:
Heavenly Mathematics & Cultural Astronomy Helmer Aslaksen Department of Mathematics National University of Singapore
How to pronounce my name? Hel-mer As-lak-sen Nothing to do with Alaska! KS not SK
My Background Grew up in Oslo, Norway B.Sc. at the Univ. of Oslo Ph.D. at UC Berkeley At NUS since 1989
I want you to have a great time in this course! I want you to enjoy the lectures I want you to learn stuff that you enjoy knowing for the rest of your life, and that you will tell your children about I want you to have fun working with your group
I love teaching this course! I have fought hard for this course! I fought hard for the name of this course! I want to make this course one of the few you will remember for the rest of your life
What will you learn? We will start with some basic facts about observational astronomy from a “hemispherically correct” viewpoint We will then look at applications with a cultural flavor
The theory of hanging clothes to dry Date: Wed, 18 Dec :44:51 From: Liew Wen Hwee Subject: The theory of hanging clothes to dry Hi Sir, Ohh my... I just discovered the theory behind my mum's "theory of hanging clothes to dry"...
Mum’s theory My mum have been telling me since I was a kid that for half of the year that she will have to hang the clothes out in the kitchen and the other half of the year in the corridor for them to dry... I was perplexed by her "theory" for a long time... I thought "wasn't the sun suppose to rise East always"??
MY MUM IS AN ASTRONOMER!!! And your lesson cleared my doubts!!! My flat lies exactly (ermmm maybe not that exact...didn't notice tat until I used the compass) in the East- west plane... And so for half of the year, the sun be in the South-east and the other half in the North- east... MY MUM IS AN ASTRONOMER !!!(ha...)...
What u have taught is of practical purpose!!! Sir, what u have taught is of practical purpose!!! (Maybe u could tell the next batch of students abt tat and they could advise their mum on how to better dry their clothes.. =)) Thanks a lot, Sir!!! Warmest regards, Wen Hwee
The mathematics of the Singapore flag
Bad Moons Rising cres.htm cres.htm Malaysia Turkey
Islamic calendar The Islamic month is supposed to start with the first visibility of the lunar crescent
The Motion of the Earth and the Moon The Earth revolves around the Sun. This determines the tropical year, which is days, just under 365 ¼ days The synodic month is the time from one new Moon to the next. The average length is days
The Lunar Year Since x 29.5 = 11, a lunar year consisting of 12 lunar months is about 11 days short of a solar year After 2 years, the error is about 22 days, and after 3 years about 33 days Solution: Add a leap month
Leap months In order to prevent Chinese New Year from moving backwards through the calendar (like the Muslim holidays do), a leap month is inserted about every third year Any month can be followed by a leap month
When is Chinese New Year? Chinese New Year moves earlier by 11 days (or 10 or 12) once or twice, but if a step would take it before January 21, it jumps later by 19 (or 18 or 20) days
The Date of Chinese New Year 2005Feb Jan Feb Feb Jan Feb Feb Jan Feb Jan 31-10
How to succeed at university? There is one thing you need to realize as soon as possible: You are no longer in JC! In JC the teacher is your friend The enemy is Cambridge At the NUS, I’m both your loving, caring lecturer and the judge and executioner
What is an easy class? What does it mean to say that CA counts 50% and exam counts 50%? We have grading quotas
Is this going to be a hard math class? There will not be a lot of formulas There will be a lot of three-dimensional visualization It is not an easy class, but I think you will find it enjoyable if you put in the work and find a good group to work with
Should you take this class? Please DO NOT TAKE this class if you do not plan to attend lectures I know it sucks to have lectures at 8 am, but I’m afraid I cannot control that I want to teach a lot of 3D geometrical concepts, and those are hard to learn on your own
Should you take this class? 2 Please DO NOT TAKE this class if you plan to rely on the webcast The webcast just shows the slides, and not my demonstrations It can help you catch things I said, but that you missed, but it will not help you with the visualizations I’m sorry, but cannot control how the webcast is done
Should you take this class? 3 Please DO NOT TAKE this class if it bothers you a lot if I occasionally say something wrong I do a lot of demonstrations with props, and sometimes involving several students I try to look at your faces to see if you understand I move around the lecture theatre
Should you take this class? 4 I try to be interactive and clear up misunderstanding when I catch them If I stood at the front and read aloud from my lecture notes, I could deliver beautiful lectures But I think it would be boring
Should you take this class? 5 I hope that you will appreciate that I try to lecture in a different way and experiment, and forgive me for sometimes fumbling when I’m being interactive
Should you take this class? 6 It is a serious problem if I say something wrong in class, and 250 students waste a lot of time trying to make sense of it When I say something wrong, I almost always catch it right away I realize that it is still annoying, and I apologize in advance, but I hope you can bear with me
Should you take this class? 7 Please DO NOT TAKE this class if you insist on a small tutorial and you are not able to come to my small tutorial I am the only person who can teach this module, and I cannot teach ten tutorial groups Sometimes there are only 3 people in my small group!
What are my weaknesses? 3D concepts are not explained well in the lecture notes I hate looking at blurred faces, so I tend to repeat things I sometimes say wrong thing while doing demonstrations
What are my strengths? I try very hard to make this a fun, creative and interactive course I try to learn new things to teach you I try to fair, clear, consistent and reasonable when it comes to rules
What do I want from you? I want you to work with me, and not try to be smarter than me
What kind of s do I not want to get? I regret my absence from the Heavenly Math exam. I must explain that it was a combination of ill health and bad luck that caused my forced absence. On that day of the exam, I had yet to recover from the stomach flu virus which i had contracted days ago. However, I still tried to make my way to the examination hall, hoping that my illness would not affect my performance.
The drama goes on! On my way to school, as I was driving, my car suddenly broke down. By the time the tow-truck came to take my car away, I was already late for the paper. Thus, I had no choice but to skip the exam.
An offer you cannot refuse I would like to request, if it is not too outrageous, for you, sir, to pass me for this module, based on my performance in the continual assessment. I had put in a lot of effort in doing my work for this module during the term, and I pray that my efforts would not go down the drain. Thank you for your time.
The greatest of them all Dear Sir, Can I interpret your refusal to explain that problem as meaning that it will appear on the exam?