Most Hindus just view eclipses as something which is an inauspicious thing and also believe negative energies are radiated from it. The word 'Grahana' itself also induces a sense of fear to many.
But we have many scriptural sources also which say that eclipse times are very auspicious times. For example, Parashara Smriti says that all water becomes as pure as the Ganges during the eclipse:
सर्वं गंगा समं तोयं राहुग्रस्ते दिवाकरे।
सोमग्रहे तथैवोक्तं स्नानदानादि कर्मसु।।
When the sun or the moon is seized by Rahu, all water becomes as pure as the water of the Ganga, so far as bathing and giving, and other religious rites are concerned.
Similarly, Padma Purana goes further in stating that all twice-borns are equivalent to Vyasa during eclipse time.
सर्वगङ्गासमंतोयंवेदव्यास समाद्विजाः ||
Now (even) when that day arrives he fights with the Moon and the Sun. The son of Simhika (i.e. Rahu) would live (in them). That would be a moment difficult to secure. (At that time) all water is like (that of) Ganga, and all twice-borns are like Vyasa. (Brahma Khanda Chapter 10 Verse 22)
Shouldn't eclipse be a very auspicious time for all these to occur? Katyayana Smriti too states:
During solar and lunar eclipses all the waters, that exist on earth and even that in a well, become like that of the Ganges.(Katyayana Smriti, Chapter 10, Verse 14)
Even the symbolic meaning of Lunar and Solar eclipse is considered auspicious and as a yogic event:
Thou learned in Vedic scriptures, O Muni! (Know that) In Ida always moves the moon, and in Pingala moves the sun. When breath moves downward through ‘Ida’ nerve and reaches the place of Kundalini, that event is called as lunar-eclipse, O, knower of truth! When breath moves downward through ‘Pingala’ nerve and reaches the place of Kundalini, that event is called as solar-eclipse, O, best of all munis! ( Skandha Purana- Suta Samhita- 2.11.49)
We have Tantric sources too where Lord Shiva explains eclipse is a very auspicious occurrence and it is a union of Shiva-Shakti. For example Matrikabheda Tantra states:
Oh, listen to me! The eclipse is a very good occasion. It is of three kinds, relating to the Sun, Moon, or fire respectively. On the forehead of Sakti (Durga) fire exists, in her left eyes glows the Moon and in her right eye the Sunshine. These three types of eclipses originate differently at the time of union of Siva with Parvati. When the left eye of Parvati is kissed by Siva, the lunar eclipse occurs. At the time of kissing of right eye the solar eclipse takes place and at the time of his kissing the fore-head the fire eclipse is generated. But as the fire is the hidden energy of Siva hence fire eclipse can not be seen outwardly. Rahu, Siva and Sakti are considered to be three qualities. The union of Siva and Sakti causes eclipse. The time when Siva and Sakti unite is thought to be an auspicious hour pervaded with divinity or bliss.
● Above all sources seem to denote eclipse as highly auspicious occurrence. But there are some traditions like closing the doors of temples during eclipse time considering it as inauspicious. Are there any scriptures which say that eclipses time are inauspicious?
● From where did the concept of Sutak during Eclipse arise? Does it have a scriptural basis?
● Do various prohibitions like not eating food, not urinating, etc.. during the Sutak period which are circulated over the Internet have some scriptural basis?
● Do the Vedas (Samhitas, Brahamanas, Aranyakas, Upanishads) have anything which tells about auspiciousness or inauspiciousness or some rules about Eclipse?
● Do the Griha Sutras, Dharma Sutras, Shrauta sutras which contains rules about many things contain rules about Eclipses?
● How do other Tantras and Tantrik sources consider eclipse? Do they give some rules also to be followed during the eclipse?
As the Katyana Smriti itself mentions that eclipse is highly auspicious it is likely that Eclipse was considered as a very auspicious moment during Vedic time. It could be such that people were told that this moment is so auspicious that do not waste your time by even eating or urinating. There are many questions in this post but they all are related to each other and are not too broad to answer also. I'm aware that many quotations present in this question itself also proves that eclipses are an auspicious occurrence, but I want to know more and also about quotations which say eclipses are inauspicious (if any). Finally, I want to sum up all the above discussion by asking one final question below:
When a person is told to chant the name of God or to meditate during eclipse, is he told such because eclipse is dangerous and inauspicious and he should chant/meditate to save himself from danger/negative elements or he is told so because Eclipse is highly auspicious and divine time and he should utilize that moment taking benefit of that auspicious time?