The 'ha' sound goes to Pushya and 'da' sound goes to Ashlesha, Hence The sound chakra is called Hodaa Chakra and to represent ether element these sounds are placed adjacent to each nakshtra. He represents the mantras and sound elements. Pushya is ruled by Brihaspati, The Guru of Devas. Yoga: Ether/Akaash Element, The Yoga is defined as Sun+Moon+Pushy Degree.Nakshatra: Airy/Vaayu Element, The 28 nakshatras are placed from Krittika onwards in groups of 7.This is a very important form of Chakra which includes all the Five Elements of Time, Called Panchanga. Click on the below image for a bigger picture. Where 28 Nakshatras are grouped in a 8x8 square with 7 nakshtras in each side. One such arrangement called Sarvotobhadra Chakra. Most important ones are divined by the Rishi's for our usage. Potentially there can be infinite number of such chakra you can draw. When you form a 8 spokes out of the nakshtras s It's called Kaala Chakra. Like you can arrange a group of Nakshtra's to form a Tortoise and it's called Kurma (Turtle) Chakra. Yes, There is also subtler forms created by these nakshatras (group of stars), Which is not directly visible on the sky by connecting the dots(stars). But the quesion is why only can you form only Scorpio, Leo, etc out of those stars?. This can be quite prominently seen on the sky. Like Scorpion type of formation is formed connecting stars in Scorpio etc. Many stars in the sky can be formed into pictures. Even The Signs in Zodiac are created thru Nakshatras. Thru Shakti's power everything gets created. The Nakshatra's represent the power of Shakti.

Sarvatobhadra chakra book