O Senhor Nrsimha é uma forma eterna do Senhor que aparece em diversos universos em diferentes momentos para executar Seus passatempos divinos.
Seu Nrsimha Caturdasi, o décimo quarto dia lunar da lua crescente do mês de Madhusudana, é, portanto, eternamente um dia sagrado, no qual Seus devotos jejuam a fim de glorificarem o aparecimento transcendental do Senhor.
Tithi
As we have discussed, the lunar month marks the time from one full moon to the next. The lunar month is divided into 30 parts, called lunar days, or tithis. The tithis are simply the different phases of the moon. Thus the first tithi starts at the moment when the moon is full -- that is, when the angle between
the moon and the sun is 180 degrees and it continues until the angle has increased 12 degrees.
Then, that much less of the moon seems bright to us: the moon is no longer completely full.
Now the second tithi starts, and it continues until the angle between the sun and moon has increased 12 degrees more. Slightly more of the bright side of the moon now has its back to us, and so the moon is even less full.
When 15 such tithis have passed, the angle between the sun and the moon has increased by 180 degrees. This time the bright side of the moon cannot be seen at all, and so we have a new moon.
Then 15 more tithis gradually pass, and the moon again becomes full. When 30 tithis have thus passed, the month ends.
The period when the moon wanes, or decreases in size, is called krsna paksa ("the dark fortnight"), and the period when it waxes, or increases, is called sukla paksa or gaura paksa ("the bright fortnight"). The words Krsna and Gaura used here are specific to the Gaudiya Vaisnava tradition.
Some lunar calendars start the month from the 0-degree position -- that is, directly after the new moon. Such calendars are called mukhya candra. Other calendars, such as the one used by the Gaudiya Vaisnavas, start directly after the full moon, with
the Krsna paksa. Such calendars are called gauna candra.
Except for the new moon and the full moon, the names of the tithis are simply counting words: pratipat, dvitiya, trtiya (first, second, third), etc. These names are the same for the tithis occurring during Krsna paksa (the dark period of the
moon) and the gaura paksa (the bright period). The new moon is called amavasya, and the full moon purnima.
Krsna paksa Gaura paksa
Tithi Name Tithi Name
1 Pratipat 1 Pratipat
2 Dvitiya 2 Dvitiya
3 Trtiya 3 Trtiya
4 Caturthi 4 Caturthi
5 Pancami 5 Pancami
6 Sasti 6 Sasti
7 Saptami 7 Saptami
8 Astami 8 Astami
9 Navami 9 Navami
10 Dasami 10 Dasami
11 Ekadasi 11 Ekadasi
12 Dvadasi 12 Dvadasi
13 Trayodasi 13 Trayodasi
14 Caturdasi 14 Caturdasi
15 Amavasya (new moon) 15 Purnima (full moon)
Because the speed of the moon in relation to that of the sun is not constant but varies, a tithi is not a fixed duration of time. Its length fluctuates between 19 and 26 hours. Therefore, since a lunar tithi does not correspond to the 24-hour solar day, a tithi may start at any time of the day.
There are certain tithis on which the followers of the Vedic culture follow various observances or celebrations. On what day is such a tithi to be observed? The general rule is that one will celebrate a tithi on that day whose sunrise falls within the tithi, though sometimes other rules come into effect.
The Ekadasi tithi is especially important, and special rules determine when to observe Ekadasi. Special rules also sometimes apply for festivals such as Sri Krsna Janmastami.
http://vcal.iskcongbc.org/VcalExplanation.txt
