Interstellar navigation represents the future of spatial travel in the cosmos, made viable by advancements in understanding the larger scope of the galaxy. It facilitates navigation on a wide scale and revolutionises the conventional terrestrial concepts of direction.

The traditional notions of North, South, East, and West become insufficient when transposed upon the vast, three-dimensional canvas of the galaxy. The challenge of interstellar navigation necessitates a system that could describe any location within this unbounded expanse.

Ascension, Declination, and Radius

At the heart of interstellar navigation are three linear coordinates: Ascension, Declination, and Radius. These distinctive measures, reappropriated from ancient astronomical terms, have been redefined to serve the needs of galaxy-wide travel.

Ascension (Asc/A) replaces traditional longitudinal measurements, indicating the horizontal direction of a point in the galaxy relative to the Galactic Core, the pulsating anchor amidst the cosmic sea. It is commonly measured in

• Degrees (Aº ranging from 0 to 360)
• Arc-hours (*, 1/10 of 1º)
• Arc-minutes (', 1/100 of 1*) and
• Arc-seconds (", 1/100 of 1').

Further precision is acquired through decimal Arc-seconds.

In layman's terms, we pick a direction - like the hand of a clock - in which we point to find our destination - but instead of a clock, which is two-dimensional, we point with a semicircle instead. Now we need to point to a direction along that semicircle.

Declination (Dec/D) offers a substitute for latitudinal measurements, showing the vertical alignment of a point with reference to the galaxy’s Planar Middle, an imaginary equatorial plane bisecting the galaxy. It is commonly measured in

• Degrees (Dº - ranging from -90 to 90)
• Arc-hours (*, 1/10 of 1º)
• Arc-minutes (', 1/100 of 1*) and
• Arc-seconds (", 1/100 of 1').

Further precision is acquired through decimal Arc-seconds.

Using Ascension and Declination from the galactic core, we have constructed an imaginary ray. Asc and Dec determine where it points - now it just needs to stop at a destination.

Radius (Rad/R) outlines the distance from the Galactic Core to any specific location. This is measured in

• Core Radii (Cr or kPc)
• Parallaxes (Parsec/Pc, 1/1000 of 1 Cr)
• Milliparallaxes (mPc, 1/1000 of 1 Pc)
• Microparallaxes (µPc, 1/1000 of 1 mPc)
• Nanoparallaxes (nPc, 1/1000 of 1 µPc)

delimited by apostrophes with trailing zeroes omitted ('). One nPc is approximately 31000 Kilometres.

Interstellar Coordinates

The correct format for interstellar coordinates is A(Unit)D(Unit)R(Unit). Some examples include:

S. Navareo - A(228º5*22'99")D(3º0*11'41")R(1'272'997)
S. Eris - A(265º8*71'03")D(-17º4*53'20")R(7'615'106)
Galathea Station - A(165º2*41'87")D(56º1*72'97")R(87'211)

Interstellar Directions

To encapsulate each of the six directions in this coordinate system succinctly, each movement in Ascension, Declination and Radius has its own shorthand: Spinward and Trailward (Ascension), Zenithward and Nadirward (Declination), and Coreward and Rimward (Radius).

• Spinward (Sw/A+) implies movement in the direction of the galaxy’s rotation, leading to an increase in Ascension.
• Trailward (Tw/A-), the reverse of Spinward, signifies traversing against the direction of the galaxy’s rotation, hence decreasing in Ascension.
• Zenithward (Zw/D+) determines ascension above the galactic plane, an increase in Declination.
• Nadirward (Nw/D-), refers to descent below the galactic plane, a decrease in Declination.
• Rimward (Rw/R+) refers to movement away from the Galactic Core, increasing in Radius.
• Coreward (Cw/R-) denotes movement towards the Galactic Core, decreasing in Radius.