Certain factors are at play for sighting the crescent on the first night of the month. These factors include “the time when the sun and the moon sets”, “the interval between the setting of the two”, “the coordinates of the sun and the moon and also the difference between the angles of them which is down to the latitudinal as well as the directional difference of the moon and the sun”, “the percentage of the crescent illumination, also known as the phases of the moon”.
Nowadays, by taking these factors into consideration, computer programmers have built some applications which work for most parts of the world. These programs can predict and draw visibility patterns of the crescent through computing and according to mathematical and scientific criteria. (the criteria for the latitudinal zone are 60 degrees south to 60 degrees north and do not work for latitudes more than 60 degrees.)
Take a look at the following pictures:
Map colors explanation based on the Yallop criterion:
In the green shaded area, the crescent should be easily visible to the naked eye.
In the yellow (similar to orange) shaded area, the crescent should be visible to the naked eye under favorable atmospheric conditions.
In the purple (similar to pink) shaded area, sighting the crescent might require special equipment and an aided eye, that is to say the crescent may become visible to the naked eye after sighting through the equipment.
In the blue shaded area, the crescent can only be sighted with an aided eye.
In areas with no color, sighting the crescent is impossible and infeasible (because although conjunction occurs before the sunset and the moon also sets after that, the crescent is not illuminated enough for it to be sighted even with an aided eye.)
In the red shaded area sighting the crescent is impractical and absolutely out of the question (because the moon sets before the sun does, in other words, conjunction occurs after the sunset).
Conjunction between the moon and the sun occurs at 10:02 a.m. UTC on Monday, June 3, 2019; but it requires more than 15 hours for the crescent to become visible with the aided eye and almost19 hours for it to be observable with the naked eye.
According to various Jurisprudential bases, the crescent visibility (for the latitudinal zone of 60 degrees south to 60 degrees north) is predicted in such a way:
(You only have to find the name of your Marja al-taqlid (the highest religious authority) and read the lines related to that particular basis. At the end of the bases which have multiple lines, it is mentioned that which region in the lines Iran belongs to.)
The first basis: The basis that “requires sighting the crescent with naked eyes” and “the horizon’s integrity conditions” (well-known jurisprudential basis of jurisconsults (in Mohammedan law) like the highest Islamic authorities: Imam Khomeini (may Allah bless his soul), َAyatollah Safi Golpaigani (M.A.B.H.S), Ayatollah Araki (M.A.B.H.S), Sayyid Muhammad Sadr (M.A.B.H.S), Bahjat (M.A.B.H.S), Ayatollah Sistani, Shabiri Zanjani, Makarem Shirazi, and Sayyid Muhammad Taghi Modarresi).
1.Sighting the crescent of the moon with naked eyes will easily be materialized at that sunset of Monday, June 3, 2019 A.D, at the far west end of Pacific ocean, only in the orange area of the map No.1 [which are: a part of Cook islands, a part of Line islands (such as Kiritimati islands, Jarvis Island, Palmyra, and Kingman Reef),Johnston Atoll, and the marine areas surrounding them] if the crescent of the moon become visible, Tuesday, June4, 2019 A.D, it will be the first day of Shawwāl1440 (L.H.) and it will be Eid al-Fitr.
- Excluding the regions in paragraph 1, for most parts of the earth (the continents of America, Africa, Europe, Asia, and Australia except the areas that will be discussed in paragraph No.3) at sunset of Tuesday, Khordad14, 1398 S.H. (and Ramadan29, 1440 (L.H.) in Iran, Iraq, and Saudi Arabia) that is equal to June4, 2019 A.D., the crescent would be visible with naked eyes, and Wednesday, June5, 2019 A.D., will be the first day of Shawwāl 1440 (L.H.) and it will be Eid al-Fitr.
3.Areas which are in pink and blue parts of map No.2; a part of the southern of Oceania [a small part of the Southeast of Australia (cities like: Traralgon, Melbourne, Geelong, Ballarat, Warrnambool, and all Tasmania) and all New Zealand] and the northeastern and the north of Asia [a part of the north of Japan (cities like: Sendai and some upper areas and all Hokkaido) a small part of the northeastern of China (cities like: Changchun, Jilin, Harbin, and more northern areas than them), the northern half of Mongolia(including Ulaanbaatar, its capital), almost all Russia except some cities like: Ufa, Kazan, Nizhny Novgorod, Moscow, and more southern areas than them] and all Estonia, at sunset of Wednesday, Khordad15, 1398 (S.H.) /June5, 2019 A.D., the crescent would be visible with naked eyes and Thursday, Khordad16, 1398 (S.H.)/ June6, 2019 A.D. will be the first day of Shawwāl 1440 (L.H.) and it will be Eid al-Fitr.
The second basis: the basis that “requires sighting the crescent with the naked eye” and the basis indicating “the sufficiency of sighting the crescent in areas where most of the nighttime fell simultaneously” (the Jurisprudential basis used by Grand Ayatollah Wahid