Saudi & ISNA Hijri Calendars

Saudi lunar dates are not calculated from the earliest visual sighting of a crescent moon in Makka.  Before 1420AH, Saudi calendar was fixed by the astronomical conjunction date based on the meridian of Greenwich. Since 1999 (1420AH) Saudi lunar month begins at sunset of the 29^th day if:

1.       The geocentric conjunction occurs before sunset; and

2.       The moon sets after the sun (in Makka).

If the two conditions are not met, then the current lunar month lasts 30 days. Of course, the moon’s actual visibility in Makka on the conjunction date or at the next sunset is not assured.

ISNA consultant, Khalid Shaukat (2006) did nothing but rehash the Saudi rule into:

                 “Islamic month begins at sunset of the day when the conjunction occurs

BEFORE 12:00Noon GMT” (3:00pm Makka time).

Obviously, the two are almost identical and a Hilal will not be visible on the dates calculated by either Saudi or ISNA criteria.