& 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 29th day if:
The geocentric conjunction occurs before sunset; and
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.
Khalid Shaukat (2006) did nothing but rehash the Saudi rule
“Islamic month begins at sunset of the day when the conjunction
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.