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To view a total solar eclipse, a new moon is required because this is the only phase in which the moon passes directly between the Earth and the sun. During a solar eclipse, the alignment must be precise to allow the moon to cover the sun completely from the perspective of an observer on Earth. This alignment occurs only when the moon is in its new phase, ensuring that the illuminated side of the moon is facing away from the Earth, while the darkened side is oriented toward the sun.
In contrast, during a full moon, the moon is on the opposite side of the Earth from the sun, meaning it cannot block the sun’s light. Other phases, including partial phases or any phase besides new, would also not provide the necessary alignment to achieve a total solar eclipse. Thus, the requirement of a new moon is central to the occurrence of a total solar eclipse.