Vijnana Bhairava Tantra · Dharana 5 · Verse 28
Ray of light from the root
Sit with the eyes closed. Imagine a thin, bright ray of light rising from the base of the body and climbing the central line. As it rises it grows finer, until it dissolves at the crown of the head and just beyond. Stay with that dissolving. The image is only a help. What matters is that attention itself grows finer, until it no longer has an object.
Older line
Contemplate the power rising from the root like a ray of light, growing subtler and still more subtle, until it grows quiet and dissolves above the crown of the head. Then Bhairava dawns.