¿ªÔÆÌåÓý

Sextant


 

Method?1
Method 1 of 7:

Finding True North in the Northern Hemisphere

  1. 1
    Locate Polaris, the North Star.?Polaris is the brightest star in the constellation Ursa Minor, also known as the Little Bear or Little Dipper. The North Star is the tip of the Little Dipper¡¯s handle, or the tail of the Little Bear.??is important to star navigation because it remains almost in the same spot all night.
    • The star is called Polaris because it appears within a degree of the Celestial North Pole and therefore appears to not move in the night sky.
    • In Greek mythology, Zeus rewarded two bears with a home in the stars of the night sky. When he threw them up there, he swung them by their tails, which elongated and formed the Ursa Minor constellation.
    • Today, most people refer to Ursa Minor as the Little Dipper instead of the Little Bear because the seven stars that make up the constellation look like a small water dipper.
    ?
  2. 2
    Use pointer stars in the Big Dipper to find Polaris and True North.?Although Polaris is visible in the northern sky at most locations north of the equator, it can be hard to spot if you don¡¯t know exactly what you¡¯re looking for. Instead,??and find Merak and Dubhe, the two stars on the edge of the Big Dipper opposite its handle. Follow these stars toward the Big Dipper¡¯s mouth to find Polaris.
    • If you go 5 times the Merak-Dubhe distance away from Dubhe, you¡¯ll be within 3 degrees of Polaris. If Polaris is clouded over, you still know where it is.
    ?
  3. 3
    Locate the Cassiopeia constellation.?Depending on your position, Cassiopeia appears as an ¡°M¡± or a ¡°W¡± in the sky. While Polaris is located at the North Celestial Pole, Cassiopeia is at the South Celestial Pole. Connect these two points to?.
    • When the Big Dipper is below the horizon, find the Great Square of the Pegasus constellation. Measure the distance from the star Alpheratz (visually a part of Pegasus but actually a part of Andromeda), to Caph, the star at the rightmost edge of Cassiopeia (W-shaped). In line with the 2 stars, measure another of these distances. You¡¯ll then be less than 3 degrees from Polaris, even if you can¡¯t physically see it.
    ?
?
Method?2
Method 2 of 7:

Finding Latitude in the Northern Hemisphere

  1. Measure the angle between the horizon and a star directly above you.?For the best accuracy, use an??or?, which lets you read the angle off its curved section. This angle measure is the same as your latitude north of the equator.
    • If you don¡¯t have an astrolabe or sextant, you can also?. Hold the??in front of you and align it to true north. Then, record the angle that is between a star and the horizon to get your latitude.
    • You can also find your latitude without the use of tools. Approximate the angle by extending your fist to the horizon and stacking fists hand-over-hand until you reach the North Star. Your extended fist is approximately 10 degrees of an angle measure.
    ?
?
Method?3
Method 3 of 7:

Finding South in the Northern Hemisphere

  1. 1
    Locate Ursa Minor.?Known as the Little Dipper or the Little Bear, this constellation resembles a small ladle with 2 stars at the end of the handle.?, then find the star at the tip of the handle and draw an imaginary line from the star down to the horizon. The point where the line meets the horizon is south.
    ?
  2. 2
    Find the Orion constellation.?Orion, or the Hunter, resembles a bent hourglass with stars making up Orion¡¯s shoulders, knees, and belt. Find Alnilam, the middle star in Orion¡¯s belt, and look for one moderately bright, one dim, and one fuzzy star hanging down from the belt. These represent Orion¡¯s sword, which points south.
    • The stars Betelgeuse and Bellatrix represent Orion¡¯s shoulders, and the stars Saiph and Rigel represent the knees or feet. Orion¡¯s belt consists of 3 stars: Alnitak, Alnilam, and Mintaka.
    • In the Northern Hemisphere, Orion is visible chiefly in the winter and early spring but can be seen late at night in the fall or before sunrise in the summer.
    • The fuzzy ¡°star¡± in Orion¡¯s sword is actually the Great Nebula of Orion, an interstellar nursery where new stars are being formed.
    ?
?
Method?4
Method 4 of 7:

Identifying South in the Southern Hemisphere

  1. Locate the Southern Cross constellation.?The Southern Cross, or Crux, is a constellation that can be seen in the Southern Hemisphere and some Southern areas of the Northern Hemisphere. Look south and locate the 2 brightest stars. Draw an imaginary line from one to the other, and this line will point south. To be more precise, extend the imaginary line until it intersects with the horizon. The intersection point is due south.?
    • The Southern Cross is made up of 4 stars total and looks like a diamond. Each of the 4 stars form a point of the cross.
    • While the Southern Cross is an important constellation (so much so that it is depicted on the flags of Australia and New Zealand), it is not particularly large. The bright pointer stars help differentiate the Southern Cross from the nearby (and slightly larger) False Cross.
    • Sigma Octantis is a star nearer to the South Celestial Pole than the Southern Cross, but it is too dim to help you find south.
    ?
?
Method?5
Method 5 of 7:

Using Star Navigation in Both Hemispheres

  1. Find Sirius, the Dog Star.?Many stars are visible in both hemispheres, including the brightest star in the sky, Sirius. Locate south by drawing an invisible line from Sirius to the horizon and noting where it intersects.
    • You can also follow the same method using Orion¡¯s Belt in both hemispheres.
    ?
?
Method?6
Method 6 of 7:

Finding East or West at the Celestial Equator

  1. Locate the star Mintaka in Orion¡¯s belt.?The torso of Orion resembles a bent hourglass, and Orion¡¯s belt consists of 3 stars: Alnitak, Alnilam, and Mintaka. Mintaka is the rightmost star in the belt and rises and sets within a degree of true east or west.
    ?
?
Method?7
Method 7 of 7:

Using Any Star¡¯s Position to Navigate

  1. 1
    Drive 2 stakes into the ground.?The??should be about 1 yard (91 cm) apart. Then, tie a piece of??between them.
    ?
  2. 2
    Select any star you see in the night sky.?While any star will work, it¡¯s best to choose one that¡¯s bright and easily visible. Then, line the star up with the tops of both stakes.
    ?
  3. 3
    Wait for the stars to move out of position with the stakes.?Earth¡¯s rotation from west to east causes the stars in the sky, as a whole, to rotate from east to west. The direction the star has moved in respect to its original position tells you which direction you¡¯re facing.
    • If the star rose, you¡¯re facing east.
    • If the star sank, you¡¯re facing west.
    • If the star moved to the left, you¡¯re facing north.
    • If the star moved to the right, you¡¯re facing south.
    ?
?
?
?