The New Moon and Ramadan in North America
Published on Sep 25, 2006 at 5:00 pm.
4 Comments.
Filed under calendars.
The word “month” originally came from “moonth”, or a cycle of the Moon’s phases. This takes about 29.5 days. The problem is that there is not an integer number of months in a year. So, most cultures dropped the Moon going through a cycle of phases as the basis of the month. The Gregorian Calendar, the dominant one used throughout the world, uses months of 30 and 31 days (except for February), which is close to the lunar month. However, there are a couple of major calendars that still use the lunar cycle for months. These are the Jewish calendar and the Islamic calendar.
Both of these calendars have similar rules for starting the month. The month is supposed to begin with the first sighting of the Moon after New Moon. The month goes until the next sighting of the Moon after the next New Moon. Now, there are a couple of issues here. First, since the Earth does not orbit the Sun in an integer number of lunar cycles, the length of the year can not be a fixed number of months and still match up with the seasons. Twelve months is a few days too short, and thirteen months is a few days too long. The Jewish calendar fixes this problem by adding an extra month as needed to keep the beginning of the year after the Autumnal equinox. The Islamic calendar, though, just ignores the problem. The year does not match up with the orbit of the Earth or with the seasons, and if you don’t like it … tough. Really, a year is an arbitrary length of time, and it is convenient, but by no means essential, for it to be equal to the length of the seasonal year (actually called the tropical year).Â
The second issue occurs if you require the Moon to be actually seen to begin the new month. Long ago, the Jewish community decided to compute the calendar, rather than requiring the actual sighting of the Moon. However, the Islamic community retained the rule to actually sight the young crescent Moon, the Hilal. This brings up some problems. What if it is cloudy? How long after New Moon can you sight the crescent Moon?Â
There have been several studies and papers published on how soon you can see the Moon after it is New. This depends in part upon the angle of the ecliptic with respect to the horizon (which depends upon location on Earth). It also depends upon atmospheric conditions. If it is hazy, they it is harder to see the young Moon. If it is cloudy, then there are obvious problems. A number of years ago, when I was a graduate student, I was overseeing operations at the university’s teaching observatory when I got a call to drop by the Physics Department office. The department chair told me that he’d gotten a call from a local Imam who wanted to come by the observatory to see if he and a couple other men could see the young Moon. It was only going to be some 18 hours past New Moon … about the limit of when it could be seen. Actually, they need not have come by the observatory, but with the Moon right at the limit of visbility, they hoped that perhaps I could point out the right direction for them to look. It was sort of hazy, and we never saw it. That wasn’t surprising for that location.
But, this illustrates a difficulty. Someone else, at a different latitude with more dry conditions with less haze, might have seen the Moon. So, different groupls of Muslims would be starting or stopping the months on different days. Obviously this can lead to confusion and discord. Muslims who work wouldn’t know until they saw the Moon if they needed to take off a day from work. And of course, different groups were observing Ramadan (the Islamic holy month) and various holy days on different days. Furthermore, there has been some argument over whether everyone who claimed to see the Hilal had really seen it, or if they were just wishfully thinking that they had seen it.
So, this year, the Islamic Society of North America announced that the Fiqh Council of North America has decided this year to encourage the use of a computed beginning of the month rather than an actual sighting. Reportedly, this decision arose from studies of the Islamic holy writings. Apparently Mohammad gave as rationale for using lunar sightings rather than calculations being that he did not trust the computational abilities of the people of that day. Now, we can know for certainly when the New Moon is (to within a second). Studies have shown how long it takes, on average, after New Moon until the Hilal is visible. So, it seemed reasonable to them to propose use of a computed month rather than relying on sightings of the Moon. You can read more about their decision here.
OK, I am not a Muslim, so I really don’t have much say here, but as an astronomer it seems like a reasonable move. I had always thought it an interesting curiosity that the Islamic calendar still relied on actual sightings of the Moon and all the confusion that such a requirement can cause. For years, the internet has allowed almost immediate dissimination of information once someone did spot the Moon, and it was never a requirement that individual Muslims see the Hilal, so long as someone had done so. But, with this new proposal, a calendar can be calculated far in advance, making planning easier on everyone.
Oh, and that makes life easier on me, too, since I have Islamic students who have special requests during Ramadan.
-Astroprof
A Ler…-- Rastos de Luz on October 2, 2006 at 5:39 am: 1
[…] “The New Moon and Ramadan in North America“, um artigo interessante sobre os ciclos lunares e os diferentes calendários. A ler no Astroprof. […]
Roger Ally on January 25, 2007 at 7:54 pm: 2
I have been advocating that Muslims use astronomical calculation to solve this problem. Sadly, one must say that the Muslim community is reluctant to embrace change and progress.
freddy farkle on October 14, 2007 at 12:43 pm: 3
I have a simple question. The next new moon is apparently around Nov 8 ‘07. I don’t know that it will be visible in Texas on that day. On what day, and at what time, and in which place in the sky should I look to try to see the new moon? I’m an old man and don’t know for certain that I’ve EVER seen a new moon. THanks.
Astroprof on October 15, 2007 at 10:16 am: 4
Hey. Actually, the new moon will be November 9, at about sunset here in TX, so the earliest that you’d be able to see it is the evening of November 10, just after sunset. That will be a very thin crescent, and it may be too small to see if you have an haze or pollution to look through.