O Son !

(’ulûm ad-dîn). The ’ulamâ’ (authorized Islamic scholars) of (the
branch of Islamic knowledge termed) fiqh wrote in their books of
fiqh the teachings which mujtahids (extracted from the Qur’ân alkerîm
and hadîth-i-sherîfs and) explained. It is permissible to
exercise oneself in the recalculation of the prescribed times,
(which have already been explained by mujtahids.) Results of such
calculations, however, are conditional on the aforesaid Islamic
scholars’ approval. It is noted in the section dealing with (the
essentials of) “facing the Qiblâ in salât” in Radd al-muhtâr by Ibn
’Âbidîn, and also in Fatâwâ-i Shams ad-dîn ar-Ramlî, that it is jâ’iz
(permissible) to determine the times of salât and direction of the
Qibla by calculation. It is noted in Mawdû’ât-ul-’ulûm: “It is fard
kifâya to calculate the prayer times. It is fard for Muslims to know
the beginning and the end of the prayer times from the position of
the Sun or from the calendars approved by Islamic scholars.”
The Earth rotates about its axis from west to east. In other
words, an overhead view of it, like that of a globe placed on a table
(with the North Pole pointing upwards), would reveal that it
rotated in a counterclockwise direction. This is called the true
(direct, prograde) motion. The Sun and the fixed stars appear to
make a revolution per day from east to west. This is called the
retrograde motion. The time between two successive meridianal
transits of a star at a certain location is defined as one sidereal day.
One-twenty-fourth of this period is one sidereal hour. The time
interval between two successive transits of the centre of the Sun
across the meridian, that is, the time between successive instants of
true zawâl is called one true solar day. Meanwhile, the Earth
moves from west to east along the ecliptic and completes one
revolution per year around the Sun. Due to this motion of the
Earth, the Sun appears to move from west to east on the ecliptic
plane, rotating about the ecliptical axis through the Earth’s centre
perpendicular to the ecliptic plane. The average speed of this
translational movement is about 30 kilometres per second, though
it is not constant. Since the orbit of the Earth on the ecliptic plane
is not circular but elliptical, the angles subtended by the arcs
travelled in equal intervals are not equal. The smaller its distance
to the Sun, the higher its speed. As a result of this movement of the
Earth, the Sun is slower than the stars by about 4 minutes per day,
thus completing its daily revolution about 4 minutes later than the
stars. Therefore, the “true solar day” is about 4 minutes longer
than the sidereal day. This extra time slightly varies from day to
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