Do you know why MOON "waxes" (grows big) and "wanes" (become small) every 15 days in a month?
Lord MOON was born to Athvi and his wife Anusuya. And he married all the the 27 daughters of Dakshan, who are the 27 Natchathirams in the sky, from Ashvini to Revati. But the MOON loved ROHINI more than all his other wifes. He spends more time with ROHINI. As usual-lah, all the other wives got jealous and complained to the father, i.e. Mr Dakshan.
Dakshan told Moon to be considerate and try being fair to the other wives too. MOON refused to listen. Where got son-in-law listen to the father-in-law, right?
The angered Dakshan then cursed the MOON , probably saying the ever famous Tamil curse, "Nee Naasamaa poa-veh". And true enough, MOON started to shrink day by day (wanes) and become diseased too in the lungs. Due to MOON's sickness, all living things also developed lung diseases too at that time. Terror-lah!
What happened then? As usual, all the celestial beings (sky, heaven, etc) teamed up and persuaded on MOON's behalf to Dakshan. "Kudumba peratchanai, keep it to yourself-lah" because your (Dakshan) curses are affecting all lives on earth succumbing to this wasting lung disease. We cannot keep quiet if other "makkels" are affected by consumption (lung diseases).
The other wives also teamed up to defend their husband & told their father like this, "kallaa-naalum purushan, pullaa-naalum kanavan". After all, "neenga father-thaane, avar vanthu our sweet hubby", ok?
Dakshan, realising he has been outnumbered, promised if MOON behaves and visit ALL his wives and spends quality time equally, MOON would be freed from his lung disease for 15 days only in a month. It will be the waxing period (SHUKLA PAKSHA) and the remaining period of the other 15 days would be the waning period where he shrinks (KRISHNA PAKSHA) because of the lung disease. That's why we are prone to chest-colds or respiratory problems when the MOON wanes. Someone there coughing? Faster go and check the calender if the Moon is waning?..Haha!
So far, MOON is still following Dakshan's order by spending two and a quarter days equally in every sign from Mesham to Meenam, hence as the MOON wanders in his celestial orbit he waxes and wanes every 15 days....what an obedient playboy!
ROHINI rules, ok!