Here's why:

* The Equator's Advantage: The equator is the only place on Earth where, over the course of a year, the celestial poles (north and south) are both below the horizon. This means that theoretically, stars in both hemispheres are visible throughout the year.

* The "Almost" Part: The reality is slightly more nuanced. While the celestial poles are below the horizon at the equator, there are a few factors that complicate the visibility:

* Atmospheric Conditions: Weather and light pollution can obscure the view of fainter stars.

* Earth's Tilt: While the Earth's tilt doesn't directly affect visibility at the equator, it does cause the sun to be high in the sky for longer periods, making it harder to see stars during the day.

* Ephemeral Stars: Some stars are simply too faint or too close to the sun to be visible even under ideal conditions.

In summary: The equator offers the most complete view of the night sky over a year, with the fewest limitations from the Earth's tilt. However, atmospheric conditions and faint stars can still affect the visibility of some objects.