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"I offer my respectful obeisances unto His Divine Grace A.C. Bhaktivedanta Swami Prabhupada, who is very dear to Lord Krsna, having taken shelter at His lotus feet. Our respectful obeisances are unto you, O spiritual master, servant of Bhaktisiddhanta Sarasvati Gosvami. You are kindly preaching the message of Lord Caitanyadeva and delivering the Western countries, which are filled with impersonalism and voidism."

I offer my respectful obeisances unto His Divine Grace Bhaktisiddhanta Sarasvati, who is very dear to Lord Krsna, having taken shelter at His lotus feet.

I offer my respectful obeisances to Sri Varsabhanavi-devi-dayita dasa [another name of Srila Bhaktisiddhanta Sarasvati], who is favored by Srimati Radharani and who is the ocean of transcendental mercy and the deliverer of the science of Krsna.

I offer my respectful obeisances unto you, the personified energy of Sri Caitanya's mercy, who deliver devotional service which is enriched with conjugal love of Radha and Krsna, coming exactly in the line of revelation of Srila Rupa Gosvami.

I offer my respectful obeisances unto you, who are the personified teachings of Lord Caitanya. You are the deliverer of the fallen souls. You do not tolerate any statement which is against the teachings of devotional service enunciated by Srila Rupa Gosvami.

Sri Yajnavalkya said: I offer my respectful obeisances to the Supreme Personality of Godhead appearing as the sun. You are present as the controller of the four kinds of living entities, beginning from Brahma and extending down to the blades of grass. Just as the sky is present both inside and outside every living being, you exist both within the hearts of all as the Supersoul and externally in the form of time. Just as the sky cannot be covered by the clouds present within it, you are never covered by any false material designation. By the flow of years, which are made up of the tiny fragments of time called ksanas, lavas and nimesas, you alone maintain this world, drying up the waters and giving them back as rain. (Srimad-Bhagavatam 12.6.67)

Let us meditate on that worshipable effulgence of the divine sun who enthuses our meditation.

Srila Bhaktisiddhanta Sarasvati Thakura is world famous as the inimitably powerful and uncompromising proponent of truth who as the founder of the Gaudiya Matha brought new focus and direction to the purely spiritual movement of Sri Caitanya Mahaprabhu. However, during youth, Srila Bhaktisiddhanta achieved fame and notoriety in a different field: that of jyotisa, the Vedic science of astronomy and astrology.

Beginning its study at age eleven, he grasped jyotisa so thoroughly as to quickly outstrip many savants with decades of experience. In 1888, at age fourteen, he started translating from Sanskrit to Bangali two classical astronomical treatises: Siddhanta-siromani, which he completed and published in 1893, and in 1896 Surya-siddhanta with its original Sanskrit verses and his own Bengali rendition. Recognizing his extraordinary proficiency and contribution in both the Eastern and Western systems of astrology and astronomical calculations, specifically for his initial unpublished work on Surya-siddhanta, his tutors Pandita Mahesa Candra Cudamani and Pandita Sundara Lala conferred upon him the title Sri Siddhanta Sarasvati when he was just fifteen years old.

With superlative knowledge and insight Sri Siddhanta Sarasvati revivified the hoary practice of jyotisa by championing its genuine principles by fearlessly protesting dilution and distortion of its pristine and immutable teachings. Had he remained in this line, undoubtedly he would have become one of the most prominent jyotisis in history. Yet on the order of his gurudeva, Srila Gaura Kisora dasa Babaji, Sri Siddhanta Sarasvati shifted his didactic efforts to preaching the Absolute Truth. His early polemic encounters in astronomy, upsetting its entrenched but mistaken orthodoxy, foreshadowed his letter battles against prevailing attitudes, trends and institutions in religion and philosophy, that were to earn him the unique appellative "lion guru."

Srila A.C. Bhaktivedanta Swami Prabhupada, the successor of Srila Bhaktisiddhanta Sarasvati Thakura who fulfilled his desire by spreading his message throughout the world, wanted to established the Vedic cosmographical view in opposition to that of current empiric science. This was part of a broader strategy to demonstrate Vedic knowledge as perfect and applicable in all circumstances, and the much-lauded contemporary scientific agglomerate as fundamentally flawed and insufficient.

These translations of Sri Siddhanta Sarasvati's renditions of Surya-siddhanta and Siddhanta-siromani have been prepared under the guidance of His Holiness Danavira Gosvami, as part of his research into the nature and form of the universe as described in Vedic texts. Although not easily intelligible, this publication importantly presents to the English-speaking world authoritative modern insights on an ancient but neglected disciple whose study has the potential to revolutionize man's perspective on the universe and his role within it.

Sri Srila-siddhanta is acclaimed throughout India as the base-text for Hindu mathematical astronomy. Nearly all calendars (pancangas) of India and hence all our daily religious works are based on the mathematics want to read this book at least once.

A lot of person consider that the Surya-siddhanta is so difficult that it is impossible to understand. Although it is difficult, it is not impossible to understand. If a person versed in preliminary knowledge of mathematics reads the chapter from beginning slowly, it is not difficult to understand. Of course, one has to do a considerable amount of computation, but it is not really that difficult.

For a new student (gaining) familiarity with technical terms is somewhat hard. If the book is read with examples then it would be much easier. If one understands the initial few things the others become automatically easy. Then taking the help of other reference books (karanagranthas) one would be able to understand the inferences contained in the original text and thus get a thorough knowledge of the subject. Our only submission is that one should not just read it once and then throw it far away on the pretext that it is difficult.

The author of the Surya-siddhanta is ever ready to come to the aid of all honest and sincere readers concerning all topics. Where the esteemed reader finds difficulties, he may find it particularly useful to review the same topics that had been discussed in earlier sections. Previous study of reference books (karanagranthas) would be helpful (too).

For calculation I have done away with the further smaller divisions of vikalas as they are not necessary.

Due to the patronage of the government, the division of fellow countrymen and financial help from the rich and the distinguished, every year thousands of Hindu young men are gaining proficiency in mathematics. It is our hope that many amongst then would respectfully pursue with great care the indigenous mathematical and astronomical sciences.

This book has 14 chapters. They are:

Chapter 1 – Of the mean motion of planets; Preface, division of time, measurement of Yogas (Yugamana), number of days, aharganas, revolutions, Mean of bhagana planets etc., conjunction and node of apsis for planets (Mandoca and sighra), Deshantara and inclination of their path to the ecliptic (paramavikshepa).

Chapter 2 – Of the true places of the planets; Causes of planetary motion, types of motions, determination of sines (jya), declination and finding out the Kendra, determination of circumference from the base and perpendicular and their results of sine and cosine, corrected position of the planets, correction of base, corrected motion, true latitude (vikshepa), length of day and night, Chara, Tithi, constellations (nakshrata), yoga, karana (portions and halves of lunar days).

Chapter 3 – Of direction place and time; Determining east-west meridian, part of solstice, equinoctial shadow, sine of co-latitude, zenith-distance, measure of amplitude, angle of the cone, Niraksha, point upon ecliptic (Lagna) and meridian ecliptic point (Dashama).

Chapter 4 – Of eclipses especially of lunar eclipse; corrected longitude of moon, measure of sun and the shadow (chaya), obscuration (Grasa), half-duration of the eclipse (Stithyardha), corrected perpendicular (Kotii), Valanamsa (degree of deflection).

Chapter 5 – Of parallax in solar eclipse; parallax in longitude of moon (Candra Lambana), parallax in latitude, solar eclipse (Suryagrahana).

Chapter 6 – Of the projection of eclipse; Parilekhadhikara

Chapter 7- Of planetary conjunctions; planetary conjunctions (Grahayutyadhidara), Akshadrikkarma, Ayanadrkkarma, disc of the planet (Grahavimba) viewing of the constellations. (Yudha)

Chapter 8 – Of the constellations; planet-constellation conjunction (Yutyadhikara), position of the constellations.

Chapter 9 – Of heliacal rising and setting; containing; rising and setting (Udayastadhikara), determination of time, portions of time (Kalangsa).

Chapter 10 – Of moon's rising and setting and elevation of her cusps; sringonnati.

Chapter 11 – Of certain malignant aspects of sun and moon; Patadhikara, Vyatipata, Determination of time, Gandaka, Bhasandhi.

Chapter 12 – Of cosmogony, geography, dimensions of the creation; Spiritual science, Kakashasthiti, Pole, Bhadrasva, Yamakoti Lanka, Ketumala, Polar star, Distance from the earth.

Chapter 13 – Of armillary sphere and other instruments.

Chapter 14 – Of the different modes of reckoning time.

A few trigonometrical terms like trijya (Radius), dhanu (arc), jya (Sine), koti (Cosine), karna (hypotenuse) have been repeatedly used, therefore, it is necessary to gain mastery over these right in the beginning. Perpendicular (Lamba), equinoctical shadow (visuvachaya) etc. are determined from the longitude of the place. Vikshepa (Latitude), kranti (Declination), sphuta etc. are depended on planetary positions.

Madhya, mandocca, sighra, circumference etc. are the tools for correction of planetary positions. The point situated on the prime meridian in the zodiac circle is the point upon ecliptic for meridian and rising. In the last 3 chapters the author of this book has detailed the ways of finding direction and time and how to build an observatory.

Sri Bimalaprasada Siddhantasarasvati