Azimuth is the horizontal angular distance measured clockwise from true north, while altitude is the vertical angular distance above the horizon. Together, these coordinates help locate a star's position in the sky.
Polaris, also known as the North Star, is located almost directly above the North Pole, making it not visible from the Southern Hemisphere. Its altitude, or angular height above the horizon, corresponds to the observer's latitude in the Northern Hemisphere. Therefore, in the Southern Hemisphere, Polaris has an altitude of 0 degrees, meaning it is always below the horizon.
Zero. (It's on the horizon.)
Instruments such as a sextant or a quadrant can be used to determine the altitude of the North Star. By measuring the angle between the North Star and the horizon, navigators can determine their latitude.
The idea is there, but a couple of important terms are swapped.The altitude of the North Star above the northern horizon is approximately equal tothe observer's north latitude.
The altitude of the North Star will not change from any point on Earth. However, the declination changes depending upon where you are and when - It is less than 90 degrees.
The altitude of the North Star, or Polaris, from Minneapolis is approximately 45 degrees above the northern horizon. This is because Polaris is located nearly directly above the North Pole, and its altitude in the sky corresponds closely to the observer's latitude. Minneapolis is situated at about 45 degrees north latitude, making Polaris appear roughly at this altitude.
Northville, MI is at 42 degrees, 26 minutes North. The altitude of the North Star is between 42 degrees and 43 degrees, depending on the time. (Polaris isn't exactly at the North Pole; it is about 1/2 degree off.)
If you are at the North Pole, you'll see the star Polaris near the zenit (altitude almost 90 degrees).
To measure the altitude of the North Star (Polaris), an instrument called a sextant is commonly used. The sextant allows navigators to determine the angle between the horizon and the star, which corresponds to their latitude in the Northern Hemisphere. By measuring this angle, one can accurately ascertain their position relative to the North Star.
As you travel northward, the altitude of Polaris, or the North Star, increases. This is because Polaris is positioned almost directly above the North Pole, so at the North Pole, it is located directly overhead at an altitude of 90 degrees. Conversely, as you move south, the altitude of Polaris decreases.
This is probably about the "horizon coordinate system". Or, it's sometimes called the horizontal coordinate system. The system uses "altitude" and "azimuth" as coordinates. The azimuth is normally measured from due North as zero. So, that's the "three reference points", probably. Altitude is the angular height of a star above the horizon. Azimuth is the angle of a star measured along the horizon, from the pole.