Astro : Evening Crescents and Morning Crescents. (& amAvAsya calculations)

Crescent Moons are the favourite of poets and Gods. And me.

Yesterday was amAvAsya. The tithi is declared for the duration of about a day and covers the duration when the Sun and Moon are 12 to zero degrees apart. For pUjA sankalapam, the tithi is taken as the the tithi at sunrise.

Curious people, like you and me like to know when exactly were the sun and moon zero degrees apart? The Sun and Moon have an approximately equal angular size of about half a degree. The moon moves through a nakSatram (13 deg 20′) in a day and the Sun through a degree.

What does this really mean? When we go stand outside?

We know that aświni nakSatram (1 st) is always to the West of bharaNi nakSatram (2 nd). That means, aświni rises first and then bharaNi follows and so on all the way to rEvati nakSatram. aświni is to the East of rEvati and so it rises after rEvati (the 27 th nakSatram).

{For the illustrative example below, I am using data from Alok Mandvagane’s Hindu Calendar Android App, with settings for B.V.Raman’s AyanAmśa. I have already discussed these things in the preceding posts.}

At Bangalore, amAvasya tithi began at 14:03:14 on Aug 31st and lasted till 14:32:50 on Sept 1st.  As per the above system. Don’t worry at this time if, your calendar has slightly different times. There are different traditions and location influences. I just want to explore the concept here.

At the time the amAvAsya tithi began, candra (moon) and ravi (sun) were at 3 deg 43′ and 15 deg 43′ of simha rAśi, ie in makhA 2nd and pUrvaphAlguNi 1st pAda, respectively. rAhu was in 20 deg 9′ of simha, ie in the 3rd pAda of pUrva phAlguNi nakSatram.

In absolute nirayana values, we have 123 deg 43′, 135 deg 43′ and 140 deg 9′ respectively for candra, ravi and rAhu. (Add 22 deg 39′ for sAyana values).

At 2:32 on Sept 1st, we have candra and ravi at 16 deg 42′ of simha rAsi’ ie 136 deg 42′, in pUrvaphAlguNi 2nd pAda. And rAhu approaching them at 20 deg 6′ of simha (140 deg 6′),  in the third pAda of pUrvaphAlguNi.

Notice that the Sun is 1′ short of 1 degree advancing, the Moon is 1′ short of 13 degrees advancing and rAhu has moved 3′ in the opposite direction. As the fun T.V. serials show, he is approaching the Sun, with his mouth open, hopeful of swallowing.

Anyways, we see that, the moment of the new moon, ie.,  of zero degree separation of Sun and Moon, marks the End of the amAvAsya tithi. This is amAvAsya anta. The old month of śrāvaNa ended yesterday at that time and a new month of bhAdrapada began. śrAvaNa and bhAdrapada together form the varSa Rtu or rainy season. And in 4 days we have vinAyaka ćaviti to look forward to.

This morning, the Moon was East of the Sun in the 3rd pAda of pUrvaphAlguNi.

So the Sun rose first, followed by the moon, making the Eastern Crescent hard to see.

But this evening, the Sun will set first, followed by the moon and if the sky is clear, we can see the Western Crescent Moon.

The moon will be slightly to the South-East of the Sun, so it’s north-west side would be the lit-up side. I hope I get to see this and take a picture and add it to this post.

To see the Eastern Crescent Moon, the Moon will have to rise first and we’ll work that out another time.

It’s getting on to be breakfast time and your’s truly is hungry!

 Expected :

Actual :