Legault Rukyat, Ijtima before Gurub, and the Convergence of Islamic Calendar

Author : Pimpinan Pusat Muhammadiyah | Saturday, May 03, 2014 15:20 WIB


Yogyakarta- The success of rukyat conducted by a French scientist, Thierry Legault, by capturing moon sighting in the smallest elongation on jitima, gave new hope of converging different method of hisab rukyat on determining new month of Qamariyah (Moon) Calendar. According to Syamsul Anwar, the chairman of Tarjih and Tajdid (Law and Reformation) Council, it has been 1500 years, but the Muslims still are not able to establish an integrated calendar system, while the Sumerians already has their own moon calendar system since 3000 BC. He thought it is time for Islam to have their own integrated calendar system, which can be accepted in the Muslim world.

How was the contribution of Legault Rukyat in the convergence of Islamic calendar? Or how was the ijtima before Gurub theory, which was believed by astrophysics Ustaz Agus Mustofa, able to answer the different views between Hisab and Rukyat? This was how Prof. Dr. Syamsul Anwar, M.A., the Chairman of Tarjih and Tajdid Council, explained on his essay entitled: Rukyat Legault, Ijtimak Sebelum Gurup, dan Penyatuan Kalender Islam (Legault Rukyat, Ijtima before Gurub, and the Convergence of Islamic Calendar). The article can be downloaded here.

If the article cannot be downloaded, here is the article:




Syamsul Anwar

(Professor of Syariah and Law Faculty, UIN Sunan Kalijaga

And Chairman of Tarjih and Tajdid Council Muhammadiyah)


Upon the initiative of the Central Chairman Muhammadiyah, the Central Office of Muhammadiyah Jakarta held a lecture on Tuesday, April 29, 2014 (29 Jumadil Akhir 1435 H). The lecture was about hisab and rukyat, presenting Thierry Legault, a French astronautics, and Ustaz Agus Mustofa as the chairman of Tarjih and Tajdid Council Muhammadiyah as the keynote speakers. The committee also invited K.H. Masdar Farid Masudi from PBNU as one of the speakers, but he could not come to the lecture. Prof. Dr. H. M. Din Syamsuddin, M. A. was responsible for the opening and closing of this event.

Three days before, Astrophotography Workshop was also held on Saturday to Monday (April 26-28, 2014) in Surabaya, inviting Thierry Legault. This event went for three days, the Ministry of Education and Culture did the opening, and Prof Din as the Central Chairman of Muhammadiyah—as well as the chairman of MUI—was also present in the event. Muhammadiyah Tarjih and Tajdid Council sent six participants. This event was supported by Ustaz Agus Mustofa, astrophysics and a writer.

Thierry Legault was able score a record of calculating the moon sighting on ijtima in its smallest elongation. This record was his rukyat of moon sighting for Jumadil Awal 1431 H on Wednesday, April 14, 2010 from Montfaucon, Lot, France, by the elongation point of Moon-Sun by 4.554o. Last year, just before Ramadhan, he was able to calculate (by using a telescope) the moon sighting for Ramadhan 1434 H on ijtima on 09:41 France Time (14:14 Indonesian Local Time [WIB]) on Monday, July 8, 2013 by the elongation point of 4.6o from Elancourt, a countryside of France.

Some people in Indonesia believed that Legault’s success might bring a new optimism to bring together and reduce the differences between hisab supporters and rukyat supporters. This optimism was not exaggerating and in some cases, it was true. For example, it is already predicted that there will be a difference between hisab and rukyat supporters for this year Ramadhan. The highest point of the moon is 0.5o in Yogyakarta on ijtima and this has not met the rukyat criteria applied by the Ministry of Religious Affair, Indonesia. Therefore, it is expected that there will be differences of when to start the fasting for Ramadhan 1435 H.

Ijtima for Ramadhan will be held on Friday, June 27, 2014 by the elongation point of 4.496o (4o29'47") from Pelabuhanratu on 15:09:39 WIB and from Yogyakarta by the point of 4.510o (4o30'37"). The elongation point is still lower than Legault’s record, 4.554o. However, it is expected that on 17:00 WIB, the elongation point might reach 4.602o (4o36'10") in Pelabuhanratu and 4.668o (4o40'04 ") in Yogyakarta. The elongation point is higher than Legault’s record; thus, it is hoped that the moon sighting will be visible in Legault’s telescope, even though it will still depend on the weather. If the moon sighting is visible on ijtima or sometime after ijtima until the sun completely sets and the government and rukyat supporters accepted this, then they can avoid the difference that might follow. Ustaz Agus Mustofa explained that they will invite Legault to Indonesia before the next Ramadhan 1435 H. Hopefully, Legault will be able to come and calculate the moon sighting for the next Ramadhan, so that they can avoid the difference.

That is the optimism side of it. Therefore, some analysts and experts proposed criteria to determine the beginning of a new lunar month, i.e. ijtima before the sun sets (al-ijtima’ qablal gurub). The base of this thought was when the moon sighting was visible on ijtima (by using telescope) and it will grow bigger as the sun sets. Even though it could not be seen with bare eyes, the moon sighting was already there, it was proven by its existence on ijtima or some time before the sun sets. This is the meeting point of rukyat and hisab by using wujudul hilal. Therefore, in the evening when the sun sets, it can be seen as the new month, because ijtima happens before the sun sets, we can just fulfill the day to the evening when the sun sets. Furthermore, the gap between ijtima and the setting of sun in the evening gives bigger opportunity for rukyat and it will be easier, if compared to rukyat on sunset. Actually the occasion of rukyat on sunset is very small, because the moon sighting in the horizon happens for a short time. Moreover, according to ijtima before gurub supporters, the ijtima is the sign of the end of the month and the start of a new month. However, since the day ends in the evening before gurub, then they continue the day until that evening. In order to complete the moon cycle, the day continues until the next day; therefore, the new month will start the day after tomorrow. As how it works, to complete a month cycle, it will take more than 24 hours, and it is irrational. However, as it works with ijtima before gurub, the completion will be on ijtima until the next day and it does not go past the next day.

Even though some cases of ijtima qablal gurub based on the success of rukyat on ijtima brings optimism, we still find some problems in some other cases of ijtima qablal gurub. Some of them can be described as follows. First, not all moon sighting on ijtima can be calculated when the elongation point is too small that the illuminated part of the moon does not face the earth; e.g. ijtima happens in the same time as an eclipse or before the eclipse approaching sunset. For example, ijtima for Zulhijah 1437 H that will fall on Thursday, September 1, 2016 at 16:03 WIB with the smallest elongation point [0.955o (0o57’) from Jakarta]. The partial moon eclipse will begin at 17:30:26 Indonesian Local Time, and the sun will set at 17:52:45 Indonesian Local Time, with partial moon eclipse. That evening in Jakarta, the moon will set some seconds before the sun does, at 17:52:04 WIB.

Second, it is highly possible that when the moon sighting is visible through telescope, the moon sets before the sun does. In other words, when the sun sets, the moon is already in the horizon, as explained in the example above. Another example, on Syawal 1437 H, the ijtima for Syawal will happen on Monday, July 4, 2016 at 18:00:58 WIB. The sun will set in Banda Aceh at 18:56:25 WIB and the moon will set at 18:50:11 WIB, meaning when the sun sets, the moon will be under the horizon. The elongation point in Banda Aceh on ijtima that day will be bigger than Thierry Legault’s record, resulting in the visibility of moon sighting through telescope.

In cases like this, a new problem arises, can the condition when the moon sets after the sunset (commonly called as the moon above the horizon, or precisely said the moon sets after the sunset) be ignored? If we use the criteria ijtima before gurub, then the new month will start that night and the next day even though the moon sets before the sun does. This is far more radical than wujudul hilal, as wujudul hilal determine the new month when the moon is under the horizon (before the sunset), then the next day is determined as the new month.

According to the supporters of wujudul hilal, the sun should set before the moon, and it is a parameter should be met. If it is not met, then they should complete the month until the 30th day and the new month starts the day after tomorrow. Their base is from Yasin verse 40 which states that the sun could not go after the moon, and night proceeds the day (tidak layak matahari mengejar bulan dan bahwa malam tidak mendahului siang). The statement “tidak layak mengejar bulan” means the position of the sun should not be behind the moon, it should be before the moon. The question will be: before the moon? Where, exactly? The statement “malam tidak mendahului siang” indicate the existence of a phenomenon in the horizon marking the change of day to night. This verse tells us of not only seeing the change from night to day, where there is also a phenomenon in the horizon, in which it actually signs the sunrise. On the contrary, this verse explains that the night should not proceed the day, meaning we should also see the change of day to night with the phenomenon in the horizon, marking the sunset. Thus, if we connect this to the previous statement that the sun appears before the moon, “appears before (behind) the moon” means the moon sets in the horizon. When the moon sets in the horizon, it marks the transition of day to night the sun’s position is not before the moon. Otherwise, the sun set before the moon and the moon is still visible when the sun sets.

Some writers stated that this interpretation is wrong, and the verse does not affirm such things because each celestial object circulates on its own orbit. It should be emphasized that the interpretation is not merely an “erklaren,” which explains the verse literally in factual-mathematically-positivistic way. The interpretation is beyond that; it could also be a way of looking and producing another ‘meaning,’ looking for something meaningful and useful for our lives, since interpretations grows and new meanings continue to form. In fiqh and tafsir study, the meanings are not merely dalatul-‘ibarah, but also dalatul-isyarah, dalatul-iqtida’, and dalalatud-dalalah. Meaning space is not a solid one and the definition is not eternal; rather, it is a dynamic one and keeps evolving. Meaning space in syariah text study is determined by the relation of makasid syariah, text (nas), and context. The truth is not merely a correspondence truth, which is applicable in nature science, but also a coherence and pragmatic truth. As long as the interpretation remains in its logic pattern, does not contain contradictions, and brings benefits to our lives, then it cannot be declared erroneous that the interpretation is accepted. 

Therefore, based on Yasin verse 40, we obtain a requirement that when the sun sets, but the moon has not set. Thus, when the moon sets preceding the sun, then that night and the day before could not be determined as a new month. The moon had to be 30 days and the new month will begin the day after tomorrow.

In order to complete a moon cycle by adding one day meaning the completion will exceed 24 hours, which means it will be irrational. The completion is calculated on the end of 29th day in a month, since the sunset that day. Thus, the completion will not exceed 24 hours. The completion could not be calculated on ijtima since ijtima happens before that day and the month ends. A month ends when the sun sets, not on ijtima, and the month as well as the day end concurrently. As the day ends when the sun sets, the month also ends on the sunset. Since the start of a new month when the sun sets, then that month end when the sun sets on the 29th day on that month so that some parameter are met. If they are not met, then they add another day, completing it to day 30th. By the addition of another day (24 hour), the month does not exceed 30 days—starts from the sunset on the beginning of the month until the sunset in the end of the month. As Nabi Muhammad SAW said, “Sometimes, a month runs for 29 days, sometimes 30 days.” The one-day addition or the completion of a moon cycle, as said by Nabi Muhammad SAW, is a part of correction to Islamic calendar. This is a unique characteristic of Qamariah Calendar since there will always be correction on every month so that there will be no excess day as seen in Urfi calendar as well as Masehi (Sun) Calendar, which is also Urfi.

Third, ijtima before gurub (qablal gurub) actually is a single parameter, when ijtima happens before gurub. Since it is a single parameter, then raises another question, which ijtima should be the parameter: is it geocentric ijtima or topocentric ijtima? Geocentricijtima happens after noon and it always precedes topocentric ijtima. Geocentric ijtima can happen before gurub, while topocentric ijtima happens after gurub. Which one should be used and why? This problem can rise in qablal gurub ijtima, but it does not happen with layered parameter criteria like wujudul hilal

For example, Syawal in 1437H. Geocentric ijtima before Syawal will happen on Monday, July 4, 2016 at 18:02:09 Indonesian Local Time. The sun will set in Banda Aceh at 18:56:25 Indonesian Local Time. Topocentric ijtima in Banda Aceh will be at 19:41:54 Indonesian Local Time, meaning it will be after the sun sets in Banda Aceh. Thus, if they determine it by employing geocentric ijtima, 1 Syawal 1437 H will be on Tuesday, July 5, 2016, because the ijtima (geocentric) will happen before gurub. However, if it is determined based on topocentric, 1 Syawal 1437 H will fall on Wednesday, July 6, 2016, because it will happen after the sun sets. By applying layered parameter criteria like wujudul hilal, there will be no problem on the ijtima type, because the parameter would not be the only ijtima, it will go through the next parameter, for example in wujudul hilal, the parameter of moon sets after the sun sets. In the case of deciding Syawal in Banda Aceh, as explained above, the moon sets preceding the sun, thus in wujudul hilal criteria, 1 Syawal 1437 H will be on Wednesday, July 6, 2016. Therefore, there will be no problem of which ijtima they should use.

The explanation above is actually about the traditional hisab and rukyat, which are done in certain location and on limited local perspective. We should think and see this problem under a global and cross-region perspective. Even though the practices of Islamic worship are done in certain location, they are related to the ones in different location. In this case, Arafah Fasting which can be practiced in our own location such as Indonesia, it is related to wukuf practice in Arafah, Mecca. Therefore, we should not only think of the new month in certain place such as Indonesia, but also its connection to other place. The change of month should be simultaneous throughout the world, between Mecca and other places, like Indonesia. This is why we should have a unifying calendar system with one principle of deciding new month throughout the world.

Rukyat could no longer able to accommodate this need. It is a reality we must humbly admit. It is not about mahzab, it is an important fact of nature we must overcome. Rukyat on the first visibility of the moon sighting have limited coverage over the earth surface. In the west side of the earth, it is possible for rukyat, but it is nearly possible in the east side of the earth. Furthermore, there are also other factors such as the earth condition and atmosphere. It is possible that the moon sighting of Zulhijah is visible in Mecca, but for some reasons, it is not visible in Indonesia in the same day; therefore, 1 Zulhijah in Mecca precedes Indonesia. As the result, the difference of 9 Zulhijah in both places take toll in the practice of Arafah Fasting for people in Indonesia. The transition from rukyat to hisab is not the heresy practice of hadist, which Nabi Muhammad SAW ordered rukyat; rather, we study more on the possibilities and further studies of his order. One of the possible meanings is faqduru lahu, which can be interpreted with hisab. Then, the hisab was further studied and applied in order to cover all situations, not only when the sky was clear. We should keep studying the possible meanings in order to fit with the facts of the nature and our needs to unify the day of worships and make a unifying Islamic calendar.

The writer always reiterates a heartbreaking reality that for 1500 years, Islamic civilization does not have a unifying calendar to this day. We only have our own local calendars which are different from one to another and only considered the local situation. There was one global calendar based on hisab urfi, but it was no longer used since it contained a number of drawbacks, i.e. it did not follow the factual moon phases in the sky.

The absence of unifying calendar was caused by the strong tradition of practicing rukyat, while actually rukyat’scoverage to the earth surface was limited and it was impossible to make a calendar—especially a global one—based on this. Therefore, we should humbly accept hisab which can be the only means of making a unifying moon calendar. The implementation of hisab is not to follow others’ mazhab, but because we live in a global world and we need one certain calendar system, which can be used by all Muslims around the world. Furthermore, we need a global calendar so that we can determine one of the worship days, namely Arafah Fasting, to happen simultaneously with wukuf in Arafah Plains. We have to put an end to the era where Muslims do not have one unifying calendar. Therefore, we should leave the thought of making local calendar. We have to make criteria which are applicable to global-based calendar. Even though some people might not be able to accept this for they still see things locally, we have to keep pushing through since it involves an important matter, the validity of our worship, and before we include another reasons, of course we should already have an offered which is approved by the name of religion and astronomy.

It is necessary to consider two time zones, east end time zone and west end time zone, in the making of global Islamic calendar. A global unifying calendar should not force Muslims in a certain place (east end time zone) to enter a new month when they have not experienced ijtima in the previous day. Instead, this unifying calendar should not hold groups of people entering a new month when the moon sighting is obviously visible in their horizon. In this context, the rukyat depending on Legault’s theory should be made based on ijtima before Gurub criteria in some cases will radicalize the arriving of new month. And in the context of global Islamic calendar, this can force a certain time zone to begin one Qamariah month on certain days when the ijtima in that area happens after the sun rises. [Further description can be found in a forthcoming book entitled Diskusi dan Korespondensi Kalender Global Hijriah].