Shiva’s quality is to give importance even to an inferior. In spite of spotted character Chandrama, the moon, was made a crown by Lord Shiva by placing it on his head. Shankar is called Shashi-Shekhar because he holds the moon on the head. ‘Shash’ is the name of a rabbit, so the moon is called ‘Shashi’ for possessing a shape like rabbit. ‘Shekhar’ means crown-jewel, so whose crown jewel is moon, he is called Shashi-Shekhar.

Moon was also present at the time of destruction of fire sacrifice of Daksha Prajapati and he got fined without any fault. In order to pacify the moon, Lord Shankar made him his crown-jewel. Chandrama also beautifully singed Samveda in praise of Lord Shankara. Bhaskar Roy comments here regarding Shashi-Shekhar—

मतिमयोऽखिलजीवसमष्टिरप्यमथि दक्षमखे हिमगुर्वृथा।
इति धिया दयया विधृतस्त्वया शिरसि तेन भवान् शशिशेखरः॥

‘‘I am knowledge personified and supreme self of all living creatures but this sinless moon got unnecessary punishment by me’’—thinking this out of compassion, Lord Shankara placed moon on his head.

Moon is said to be an emblem of mind and mind is an instrument of spirit-self. Mind can not become an ornament for Shiva, until it imbibes divine knowledge and Godly qualities. Shankara always sustain the moon of second phase just to denote the subtlety of impersonal knowledge of the self. Mind liberates the soul from bondage by receiving the paramount light of Shiva. The black dots in the moon represent the mental avarice. Becoming free from such contaminations is the true worship of Shashi-Shekhar.