ANSWER : The Lord Himself says “ma:sa:na:m ma:rgasi:rsho:ham,” in Bhagavad Gi:tha. “which means “I am the month of Ma:rgasi:rsha among months.”

ANSWER : The time when the divine surfaces in us is the pious uththara:yana (the six months when the Sun moves northward). The month preceding this period is Ma:rgasi:rsha and is like the bra:hmi: muhu:rtham, suitable for undertaking pious, sa:thvik deeds. The month suitable for undertaking uplifing work is Ma:rgasi:rsha.

ANSWER : (1) Vaikunta Ekadasi (Mukkoti Ekadasi)
(2) Krishna told Arjuna Bhagavad Gita(BG appearance day)

Note : Today is special for 2 Reasons they are as follows:- (1)Vaikunta Ekadasi. (2)Gita Jayanthi. Vaikunta Ekadasi Importance:-Vaikunta Ekadasi is the sukhla Paksha Ekadasi in Dhanurmasam. According to the Vishnu Purana, fasting on Vaikuntha Ekadashi is equivalent to fasting on the remaining 23 Ekadashis of the (Hindu) year. Vishnu opened the gate of Vaikuntham (his abode) for two demons(Madhu and Kaitabha) in spite of their being against him. They also asked for the boon that whoever listens to their story and sees the image of Vishnu coming out of the door (called Dwar), called Vaikunth Dwar, will reach Vaikunth as well.In many Divyadesams Vaikunta Dwaram (Uttara Dwaram) will be opened on Vaikunta Ekadasi and Dwadasi. (2)Gita Jayanthi Importance:- Gita Jayanthi, also referred as Bhagawad Geetha Jayanthi, is the day when the Bhagvad Gita was rendered by Lord Krishna to Arjuna in the Kurukshetra on the first day of the famous 18-day battle in the Mahabharata. Gita Jayanthi falls on the Ekadashi day of Shukla Paksha (the bright half) of the Margashirsha month (November-December) in traditional Hindi calendar.

ANSWER : The Anadhyayana kaalam (period of non-recital of prabhandham) is observed from Karthigaiyil Karthikai(from Karthika Pournami) to Thai Hastam(which happens to be Sri Kooratazhwan’s appearance day). Ths is the custom in homes. For temples, some follow this, for some others there are some variations.

Note : The reason for Anadhyayana kaalam is for the fact that when Thirumangai Azhvar started the Adyayana utsavam in Srirangam, the vigraha of Swami Nammazhvar was brought from Azhvar Thirunagari and then once it completed it was to be taken back. Later the vigrahas of other acharyas and azhvars from various divyadesams were also brought to Srirangam. This used to take alot of time, as few hundreds of kilometres need to be travelled. Since most of the Sri Vaishnavas were involved in the transfer of the divine vigrahas of Azhvar, recital of divya prabhandam at home did not happen. Only during the adhyaya utsavam, the recital happened. This practice carried over and is referred to as the Anadyayana kaalam. Since Thirumangai Azhvar started the Adhyayana utsavam, the anadyayana kaalam starts from karthikayil karthika his tirunakshattiram,.

ANSWER : Thiruvoimozhi is recited during Iraapathu and the verses of other Azhvars (other than the iyarpa section) are recited during Pagal pathu during the Adhyayana utsavam celebrations.
Adyayana utsavam is cekebrated in most divyadesams that follow Ramanuja sampradaya. Check notes for information.

Note : In Srirangam there is one more day added. Because, Sri Thirumangai Azhvar started it, the day before the Pagal Paththu Uthsavam first day, Namperumal listens to ThiruNedunthandagam of Sri Thirumangai Azhvar.
So, originally started as ten days festival by Sri Thirumangai Azhvar and was later modified as Twenty one days (+one day for
ThiruNedunthandagam) by Swami Emberumanar.
Thiru Adhyayana Utsavam is celebrated for 23 days in Tirumala. This is usually held from the night of Amavasya that occurs before Vaikunta Ekadasi in Dhanurmasa. SInce vigraha of Swami Nammazhvar is not there in Tirumala, Vishvaksenar and Swami emperumanar conduct this festival here. Lord Venkateshwara exclusively listens to Ramanuja Nootrandhadhi on the last day as a mark of respect to the great acharyar who offered sankhu chakram to the Lord and thus re-established sri vaishnavism.

ANSWER : Adyayana utsavam is celebrated around Suklapaksha ekadasi of Dhanurmasam (Ma:rgasi:rsha). The celebrations start 10 days before this ekadasi(Vaikunta ekadasi) and go on 10 days after it, totalling to 21 days. The last day is devoted to the recitation of iyarpa. The first 10 days is PagalPathu and the next 10 days starting ekadasi is Iraa pathu.