Navigation Using the Crux Constellation (Southern Cross)

Navigation Using the Crux Constellation (Southern Cross) - Survival

Before impressive GPS systems and even a compass, we navigated using the stars. In the southern hemisphere the Crux constellation, better known as the Southern Cross makes this easy. Once, you have the constellation within your gaze, it is a simple matter of connecting the dots. Trace a line on the long axis of the cross, between Gamma and Alpha Crux. Take this distance and multiply it by four and a half, then trace a line directly down. This will provide a southerly direction. If it were not for the continuous development of our navigational skill, the world will not be mapped. The average person now simply uses triangulated GPS positioning, however, for most of our history this was not an option. In ancient days we used the stars to find our way, though it may not be perfect, it can be accurate and even fun. Let's look at a basic way to navigate using stars in the southern hemisphere.

The most prolific of which is the Southern Cross or Crux constellation.

The crux constellation borders the southern section of the Centaurus constellation. The crux constellation is visible to the southern hemisphere and tropical latitudes of the northern. Due to the precession of the equinox over vast spans of time, the Southern Cross would have been visible to most of the northern hemisphere about 10 000 years ago, however, it is currently still moving toward the south pole. It is estimated that in roughly 12 000 years it will once again be seen by most of the northern hemisphere.

The crux consists of five primary stars.

The brightest and most southerly star in the cross is Alpha Crusis or Acrux. This is a multiple star system that with the naked eye seems like one star. It is the 13th brightest star in the night sky.

Moving in clockwise order, we find Beta Crucis also named Mimosa. This binary star system is the second brightest body in the Crux constellation and 19th brightest in the night sky.

Continuing clockwise is Gamma Crucis or Gacrux, the third brightest in the Crux. This is one of the closest red giant stars to our solar system and 26th brightest star in the night sky.

Continuing clockwise we find Delta Crucis also known as 'the pale one'. The fourth brightest in the constellation and the 128th brightest star in the night sky.

These above-mentioned stars are the what defines the constellation as the Crux, however, the last star in the constellation and faintest of them all lies between Alpha and Delta Crux. This is Epsilon Crucis, also known as Ginan.

Finding south using the Southern Cross is quite simple. There are two primary ways.

First: Trace an imaginary line from Gacrux to Acrux and continue onward. Then take the distance between the two stars and multiply it by four and a half times following the initial line. When this measurement ends, trace a line directly to the horizon. Although it may be off by a few degrees, it will provide an accurate southerly direction.

Second: Close to Beta Crux are two other very bright stars known as the pointers. These are Alpha and Beta Centauri. To determine south, trace a line between Alpha and Beta Centauri, then trace a line perpendicular to it. Keep the line in mind. Then trace a line between Gacrux and Axrux and continue onward. Where the perpendicular line of Alpha and Beta Centauri crosses the line traced from the Crux, a line is then traced to the horizon. This will also provide a fairly accurate Southerly Direction.

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