By constraint on the pole star—knowledge of the motion of the stars.
Dhruva nakshatra in Sanskrit means “immovable star” and in the Mahabharata epic is a term for the polar star. With this context in mind, when one fixates one’s attention on an immovable object one becomes aware of all other movements around it. Hence the motion of other stars around the immovable polar star known as Dhruve when constraining one’s attention on it.
Every external focus designed for the attainment of Siddhis has also its internal counterpart in as much as what’s here is also elsewhere (‘as above so below’, ‘as within so without’). Dhuva also stands for the roof of our internal space, our own immovable internal star at the Ajna Chakra.
Focusing at Ajna ('the star to the astral gateway') allows us to become aware of our destiny as it is after all 'written in the stars'.
Only the Self is immutable. Everything else comes and goes, has its time and its own expression.
It is the dance of existence within the cycle of generation, order, dissolution and regeneration.