The Avestic texts we know are almost all recitatives of various Mazdean ceremonies. Even so, our knowledge of Mazdean rituals is very limited. Modern editors of the Avesta have based the edited text on Pehlevi manuscripts. For the recitative of the long ceremony, these give only one complete ceremony: the Yasna. For the other ceremonies (Wīsperad and the intercalation ceremonies), they give only a selection of texts, texts which still require translation. Consequently, the Pehlevi manuscripts and Geldner's edition of the Avesta do not provide information on the different variants of the long liturgy. These variants are, however, described in the sāde manuscripts. Today, we know that the descriptions of the ceremonies that appear in the sāde manuscripts continue a tradition that goes back at least to Sassanid times and possibly even earlier. As a result, we now know that the ceremonies described in the Avestic manuscripts as early as the 13th century were already being celebrated in a very similar way in Sassanid times. They must even be very much earlier, but we are unable to give a precise date for the origin of these ceremonies as they appear in the manuscripts.
The internal analysis of the Avestian texts combined with comparative data on Vedic ritual and information from the Nērangestān and sāde manuscripts present us with a more complex view of Mazdean ritual than Geldner's edition. The standard Yasna, the only fully edited recitative of the long liturgy, is the daily morning ceremony. There is also a similar ceremony, the Yašt ī Rapihwin "midday ceremony", which is celebrated only during the summer months. The Wīsperad, on the other hand, is the solemn ceremony celebrated during the great annual festivities (the six Gāhānbār and the five days of Frawardīgān). During the great festivities, each day combined five ceremonies (auroral, morning, midday, afternoon and evening) in summer and four in winter (auroral, morning, afternoon and evening) for five consecutive days. The sacrificers could change, and the substitution of the priestly college took place after the first pressing of the haoma, at the end of the Hōm Stōd. The title of the Wīsperad ceremony refers to the possibility of celebrating it during different sacrificial moments.
The main ceremony in the combined celebrations of four or five ceremonies a day was the auroral ceremony (theušahina ceremony). Indeed, at the base of the text of the "articulations of the day" of all the ceremonies of the long liturgy is a version of the sacrificial moments of the day that begins with theušahina. Also, in Old-Avestic texts, the sacrificial moment par excellence is theušahina and not the hāuuani "morning" as in the standard Yasna and in most ceremonies attested in manuscripts. In the course of history, sacrificial moments have increased from three (in Old-Avestic texts) to five in the long liturgy of Late-Avestic. What's more, there's a similar dispute in the Mazdean world to that found in the Vedic world over the exact morning sacrificial moment: the auroral sacrifice that begins before sunrise is opposed to the morning sacrifice that begins with sunrise. So much so that the auroral sacrifice seems to be older and more solemn in the Avesta, the daily Yasna ceremony and most of the ceremonies attested in the manuscripts are morning ones. The Wīsperad with the double recitation of the Yasna Haptaŋhāiti may originally have been an auroral sacrifice with an original solution to the polemic between auroral and morning sacrifice: an auroral sacrifice (the first Yasna Haptaŋhāiti) and a morning sacrifice are celebrated at sunrise (the second Yasna Haptaŋhāiti).
In addition, the auroral ceremony is the basis of the intercalation ceremonies. The daēnā, which has inherited some traits from the aurora, makes it possible to see the beyond, access the world of the gods and consequently communicate with divinity. During auroral ceremonies, one obtains auroral "vision", the daēnā, and communication with the divinity is therefore possible. This is the moment for the frašna "Interview" with Ahura Mazdā and can therefore be included in the ceremony at this point. Most of the texts in late Avestic (all the frašna) were composed to be recited during the long ceremony.
