Zenith

Definition

The zenith is the point in the sky that is directly above an observer's position on the Earth's surface. It represents a 90-degree angle from all points on the horizon.

5 Must Know Facts For Your Next Test

1. The zenith is always located directly overhead regardless of the observer’s geographical location.
2. Astronomers use the zenith as a reference point for measuring celestial objects' positions.
3. At the equator, celestial objects can pass through or near the zenith if their declination is zero.
4. The altitude of the zenith is always 90 degrees above the horizon.
5. In astronomy, observing stars at their highest point, when they cross the meridian near the zenith, reduces atmospheric distortion.

Review Questions

• What is the definition of zenith in astronomical terms?
• How does an object's position relative to the zenith impact its visibility and clarity?
• Why do astronomers prefer to observe celestial objects when they are near or at their zenith?

Related terms

Horizon:

The line where the Earth's surface appears to meet the sky.

Nadir:

The point in the sky directly below an observer, opposite to the zenith.

Altitude:

The angular distance between an object in the sky and an observer's horizon.