Abu Sa'id Ahmed ibn Mohammed ibn Abd al-Jalil al-Sijzi (c. 945 - c. 1020, also known as al-Sinjari and al-Sijazi; Persian: ابوسعید سجزی; Al-Sijzi is short for "Al-Sijistani") was an Iranian[3] Muslim astronomer, mathematician, and astrologer.

He replaced the old kinematical trisection of an angle by a purely geometric solution (intersection of a circle and an equilateral hyperbola.)

Al-Biruni tells us that Al-Sijzi invented an astrolabe, called "al-zūraqī", whose design was based on the idea that the Earth rotates:[6] I have seen the astrolabe called Zuraqi invented by Abu Sa'id Sijzi.

I liked it very much and praised him a great deal, as it is based on the idea entertained by some to the effect that the motion we see is due to the Earth's movement and not to that of the sky.

It is just for the physicist to see if it is possible to refute it.Al-Biruni also referred to Al-Sijzi as a prominent astronomer who defended the theory that the earth rotates in al-Qānūn al-Masʿūdī.