It goes on the whole day If you want a Darshan, then you stand in line and keep going through, You will get all of few seconds. Best to do sign up for an Abhishekam-- I would recommend early morning so they crowd will be comparatively less and you will get a peaceful time with Ambal. You would have to sit on the floor before the deity while the Abishekam is going on. The other major times are at noon, evening at around 6, and night at around 8. The crowds then will be substantially larger.
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