What is the validity of the statement: Astronomical calculations are used to deny the sighting of the crescent, but not to establish it?

Question:
Honorable Shaykh, may Allah grant you success. Who says that astronomical calculations are used to deny the sighting but not to establish it, is his statement correct?

Answer:
No, astronomical calculations do not enter into acts of worship; acts of worship do not involve astronomical calculations. It is based on sighting, my brother. The Fajr prayer is based on the appearance of the dawn; do you see the dawn or not? It is not based on calculation alone. The Zuhr prayer is based on the sun passing its zenith; do you see the sun passing its zenith? Asr is when the shadow of a standing object equals its length; the wall’s shadow equals the person’s shadow, the person’s shadow equals the stick’s shadow, the stick’s shadow equals its own shadow; this is the time of Asr. This is something you see. Maghrib is based on the setting of the sun; look at the setting of the sun. Isha is based on the disappearance of the red twilight; look at it. It is all based on observation, my brother, not on calculation alone.
The month is determined by the crescent for entry and exit, or by completing the count. This is not difficult for people; rather, it is what makes things easy for people, and everyone knows it, praise be to Allah. The religion is ease. Allah has not burdened us with calculations, the details of calculations, or the degrees of the stars. Allah has not burdened us with this. Yes.