## What is observed altitude?

The observed altitude is the altitude that a star is seen to be with a telescope. This is where it appears in the sky. The observed altitude is always greater than the the apparent altitude, which is the altitude that a star would be at, if there were no atmosphere (sometimes called “true” altitude).

## How do you find apparent altitude?

Index Correction refers to any mechanical offset in the sextant that could not be corrected, and Dip Correction comes from the height of the observer’s eye above the local horizon. These terms are added together with the Sextant Altitude (the observed angle measurement using a sextant) to get our Apparent Altitude.

What is true altitude in navigation?

4) True Altitude True altitude is the vertical distance of your airplane above sea level. Commonly expressed as “feet MSL” (feet above mean sea level), many of the airspace altitudes, terrain figures, airways, and obstacles you’ll find on aeronautical charts are expressed in true altitude (MSL), feet above sea level.

What altitude is measured between the body and the horizon as seen from the surface of the sea?

This is the angular difference between the altitude measured between the apparent horizon and the body as seen through the observer’s eye and the altitude which would be measured between the body and the horizon as seen from the surface of the sea.

### What is the difference between observed altitude and computed altitude?

The calculated altitude (Hc) is compared to the observed altitude (Ho, sextant altitude (Hs) corrected for various errors). The difference between Hc and Ho is called “intercept” and is the observer’s distance from the assumed position.

### What is Parallax in altitude?

parallax in celestial altitude The angle between the straight line from a celestial body to an observer, and the straight line from the celestial body to the center of the earth.

What is relative altitude?

Definitions of Altitude (ALT) AGL: Altitude above Ground Level: the altitude of the vehicle above whatever is directly below it. Relative: Relative altitude above HOME/ORIGIN position’s altitude. This is what is displayed in the ground station and OSD as the vehicle’s altitude.

What does calibrated altitude mean?

Calibrated altitude is corrected for nonstandard atmospheric conditions. It is the actual height above mean sea level, as if measured with a tape measure. Elevations of airports, mountaintops, towers and other obstructions are given in true altitude.

#### What is sextant altitude?

It is the angular height of an object, above the visible horizon or as read from the arc of a sextant, before correction for index error if any. Observed altitude: This is the angular height of an object above the visible horizon as read from the arch of the sextant and correction for index error.

How do you name a true altitude?

Points to pounder prior to solving problems of this chapter.

1. True Altitude is named same as Azimuth.
2. MZD is named opposite to T Alt.
3. If MZD and Dec are of same name so add and retain same name and If of opposite names then subtract the smaller one from the larger one and retain the name of the larger one.