Tag festivals of India

The other one is Chandra Manasa where one follows the waxing and waning of the Moon.

In Surya Manasa, the Stars, Nakshatras are given importance for calculations of festivals and auspicious occasions.

Chandra Manasa takes into account the wacing and waning of the Moon, called the Thithis. Nakshatras 28 and Thithis are fifteen.

For January Vaikuntha Ekadashi...
Next Day Parana Time = 06:45 to 08:32
On Parana Day Dwadashi End Moment = 08:32

Ekadashi Tithi Begins = 09:09 on 31/Dec/2014
Ekadashi Tithi Ends = 08:40 on 1/Jan/2015
Thitihs are taken into account for calculation of inauspicious occasions like death and performance of Death related rituals like Srardha.

The period from the New Moon Day to Full Moon Day is called Sukla Paksha, which is considered auspicious and for auspicious occasions days/dates are fixed during this period.

However major Vows or Vratas are observed during the waning Moon period, Krishna Paksha.

Vaikunta Ekadasi,Shivratri,Shashti(for Lord Subramanya), Ganesh Chaturthi are observed in this period.

Of the major Vrats, Vaikunta Ekadasi is observed in Onesiance to Lord Vishnu and this is believed to grant many a boon, including the ttainment of Lord Vishu'sfeet at His Abode, The Vaikunta.

This is observed on the eleventh day of the Moon Cycle and the one that falls during Sukla Paksha is important.

However, most important Ekadasi which occurs in the month of Mrigasira, Margazhi in Tamil,December-January in Gregorian calendar, is of special importance and is celebrated on agrand scale in sri Vaishnava Temples, Sriranagam and Srivilliputtur are famous for this occasion.

Early in the morning of the Vaikunta Ekadasy Day, the doors leading to the Inner Sanctum of Lord Vishnu is opened and people enter through this. Special poojas are performed.