The Solar Treatise with the Illumination of the Hidden Meaning

In Chapter 5—Lunar parallax and solar eclipses specifically 'avanati' or the depression of the sun.
In Chapter 6—On the projection of eclipses Parilekhadhikara: the graphical representation or drawing of an eclipse.
In Chapter 7—On planetary conjunctions, including visibility corrections Aksha-drikkarma and Ayana-drikkarma, the size of planetary disks, and the observation of planetary wars astronomical 'battles' when planets appear very close together.
In Chapter 8—On the conjunction of stars and planets, and the positions of the lunar mansions Nakshatras.
In Chapter 9—On the rising and setting of celestial bodies, the determination of time, and degrees of time.
In Chapter 10—On the elevation of the Moon's horns the phase and appearance of the crescent moon and moonrise.
In Chapter 11—On the nodes Pata, particularly the malignant aspects Vyatipata, time determination, and transitional points Gandaka and Bhasandhi.

In Chapter 12—Spiritual science, the arrangement of the celestial spheres, and the geography of the sacred mountains and cities: Meru, Bhadrashva, Yamakoti, Lanka, and Ketumala; also the distance of the stars from the Earth.
In Chapter 13—On the construction of the armillary sphere Gola and astronomical instruments.
In Chapter 14—On the determination of various systems of time.

Several trigonometric terms are used continuously, such as Radius Trijya, Arc Dhanu, Sine Jya, Cosine Koti, and Hypotenuse Karna; therefore, these should be understood beforehand. Parallax and the equinoctial shadow are determined by the latitude of one's own country. Latitude Vikshepa, Declination Kranti, and true positions Sphuta are based on the actual placement of the planets. The Mean position Madhya, Apogee Mandochcha, Perigee Shighra, and Circumference Paridhi are the sections used to calculate true positions.

The point of the zodiac which lies beyond the meridian is the tenth house and the rising sign Lagna. In the chapter on the three problems Triprashnadhyaya, it is shown how to determine direction and time, and later in the chapter on instruments, the method for making instruments and instructions for building an observatory Manmandir are given. Before concluding this introduction, many thanks are repeatedly given to the ornament of the assembly of virtuous men and the refuter of heretical views, the honorable Pandit Jwalaprasad Mishra and the honorable Vimalaprasad Siddhantasaraswati-ji, because great assistance was received from these gentlemen in the translation of this text. For the benefit of students, suitable and proper examples have also been provided in this book. Enough has been said.

Year 1952 of the Vikrami Era approx. 1895 CE.
Chaitra, Dark Fortnight, 2nd day, Sunday.