According to Osho, in tratak the object is incidental; the act of unwavering, alert gazing stills the mind’s habitual movement. An open sky, a master’s photo, or darkness are merely different anchors: sky/light can aid wakeful expansiveness, darkness invites inwardness but risks sleep, and a master’s image can add love—useful unless it triggers thinking. What matters is total, present awareness.
What you gaze at doesn’t matter—just look without blinking and stay fully awake; sky, a master’s face, or darkness only help in different ways.