# Altitude

Also called: elevation, height above the horizon.

How high an object is above the horizon, from 0° on the horizon to 90° straight overhead.

Altitude, with [azimuth](https://astropilot.space/glossary/azimuth), tells you where to look. Low objects shine through much more air: they're dimmer (see [extinction](https://astropilot.space/glossary/extinction)), redder and blurred by [seeing](https://astropilot.space/glossary/seeing). Most objects are best near their highest point, when they cross the [meridian](https://astropilot.space/glossary/meridian).

**At the eyepiece:** Measure altitude with your hand at arm's length: a fist is about 10°, so the horizon to overhead is about nine fists.

**In AstroPilot:** AstroPilot gives every object's altitude and direction, the hours when it's above your minimum altitude, and when it's highest.

**Related:** [Azimuth](https://astropilot.space/glossary/azimuth.md), [Zenith](https://astropilot.space/glossary/zenith.md), [Meridian](https://astropilot.space/glossary/meridian.md), [Extinction](https://astropilot.space/glossary/extinction.md), [Angular size](https://astropilot.space/glossary/angular-size.md)

From the AstroPilot astronomy glossary: https://astropilot.space/glossary/altitude