''Sullam al-sama, also known as Resaleh-ye Kamaliyyeh (

Arabic Arabic (, , or , ) is a Central Semitic languages, Central Semitic language of the Afroasiatic languages, Afroasiatic language family spoken primarily in the Arab world. The International Organization for Standardization (ISO) assigns lang ...

*: سُلَم السماء, Transliterated as Sǒllam os-Samā'), meaning "''The Ladder of the Sky''" or "''The Stairway of Heaven''", is an

astronomical Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall evolution. Objects of interest include ...

treatise written by the

Persian Persian may refer to: * People and things from Iran, historically called ''Persia'' in the English language ** Persians, the majority ethnic group in Iran, not to be conflated with the Iranic peoples ** Persian language, an Iranian language of the ...

mathematician and astronomer Jamshid Kashani in 1407 about the determination of the distance and size of heavenly bodies such as the

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

, the

Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...

and the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

The text

Kashani finished writing the book on 1 March 1407. He mentioned in the preface of another book of his, ''Meftah al-Hesab'' (lit. "The Key of Arithmetic"), that: "I studied all books on astronomy that the scientists had written before me and I realized that they had many difficulties and disagreements about the determination of the size or distance of the astronomical objects like Mercury or

Venus Venus is the second planet from the Sun. It is often called Earth's "twin" or "sister" planet for having almost the same size and mass, and the closest orbit to Earth's. While both are rocky planets, Venus has an atmosphere much thicker ...

to the Sun. So I decided to write this book and I named it Sullam al-sama' to be a guide for the wise."

Series adaptation

The book shares its title with a TV series about Kashani produced in Iran in 2008.

Footnotes

{{Islamic astronomy 1407 books 15th-century Arabic-language books Iranian books Astronomical works of the medieval Islamic world