Galactic Coordinates

[Ben Seeman]

While working on my next DH article I was referencing the map made by Keith Curtis for Terran Empire and discovered a coordinate system that could be used to pinpoint locations on the map.

 

The map is broken up into degrees as well as concentric circles every 5,000 LY. Using these measurements (and looking at the map) we can then say that Earth is located at (0,30) meaning it is on the 0 degrees line and is 30,000 LY from the center of the galaxy. Varan's coordinates would be approximately (213, 35) and the Xenovore homeworld would be at approximately (63, 36).

 

I don't know if anyone else has used this system or is interested in this, but I found that it makes it easier to reference the location of a place using coordinates instead of using a physical description.

[Fitz]

Re: Galactic Coordinates

 

I've been using this exact system, with a bogus 3rd dimension thrown in just for the sake of SoB. If I were *really* anal, I'd work out how that 3rd dimension affects travel times, but fortunately me I'm not

[lemming]

Re: Galactic Coordinates

 

That's a description of the Polar coordinate system.

[keithcurtis]

Re: Galactic Coordinates

 

I used to have an old Star Trek Navigational Handbook (and totally awesome maps) that used that as the basis of explaining the terminology, "Scotty! Deep space, 210 Mark 1"

 

Keith "No-prize to whoever identifies where those coordinates were used" Curtis

[BobGreenwade]

Re: Galactic Coordinates

 

I've caught on with the degrees, but a reference for the concentric circles has escaped me until now. I think this should become the "official" galactic reference system for the Terran Empire era. I'd been wanting one, so I could describe the location of Vexinar, the planet where the last 2/3 of my opening adventure takes place -- and this puts it very neatly at (82, 26).

 

My suggestions for other periods: For pre-Terran Empire, use Earth as the center and the galactic core as zero-reference. For Galactic Federation, use Malagar as zero-reference and use grads (400 per circle) instead of degrees.

[SirViss]

Re: Galactic Coordinates

 

..."Scotty! Deep space, 210 Mark 1"

 

Keith "No-prize to whoever identifies where those coordinates were used" Curtis

 

Not sure, but the episode with "Nomad"?

[keithcurtis]

Re: Galactic Coordinates

 

Not sure' date=' but the episode with "Nomad"?[/quote']

Good job, Sir Viss!

You're No-Prize is in the mail.

 

Keith "Hope I put enough postage on it" Curtis

[BobGreenwade]

Re: Galactic Coordinates

 

Another thought... what about the "Z" coordinate for a sector? My inclination would be to indicate it by light-years from the galactic equator, with positive being North (away from the viewer in the published map) and negative being South. Thus my coordinates for Vexinar would be (82, 26, -1).

[Drakkenkin]

Re: Galactic Coordinates

 

I would think it would be best to use Spherical Coordinates. So just use another angle. (P, theta, Phi)

 

P = distance

theta = angle along the galatic plain (earth could be 0 degrees)

Phi = the angle above or below the Galactic plain.

 

Drakkenkin

[lemming]

Re: Galactic Coordinates

 

I would think it would be best to use Spherical Coordinates. So just use another angle. (P, theta, Phi)

 

P = distance

theta = angle along the galatic plain (earth could be 0 degrees)

Phi = the angle above or below the Galactic plain.

I think that would work well since we do have three dimensions to work with.

[BobGreenwade]

Re: Galactic Coordinates

 

I'd be more comfortable using cylindrical coordinates rather than spherical, since our galaxy is more of a cylinder (wheel) then a globe, but if we do use an angle rather than a distance I think it would be easier to use one of the poles as "zero" rather than the galactic equator.

[keithcurtis]

Re: Galactic Coordinates

 

Another thought... what about the "Z" coordinate for a sector? My inclination would be to indicate it by light-years from the galactic equator' date=' with positive being North (away from the viewer in the published map) and negative being South. Thus my coordinates for Vexinar would be (82, 26, -1).[/quote']

 

I'd have to double check, but I'm pretty sure Galactic North would be toward the viewer. This is a "top down" map as much as that means anything in space.

 

Keith "Space-Fodor" Curtis

[BobGreenwade]

Re: Galactic Coordinates

 

I'd have to double check' date=' but I'm pretty sure Galactic North would be toward the viewer. This is a "top down" map as much as that means anything in space.[/quote'] My reasoning is as follows: since the sun rises in the east, the earth rotates to the east. Eastward, therefore, equals spinward. If north is in front of me, east is to my right. If I stand at the galactic rim with spinward to my right, I'm facing away from the reader. Thus, Galactic North is away from the reader.

[keithcurtis]

Re: Galactic Coordinates

 

My reasoning is as follows: since the sun rises in the east' date=' the earth rotates to the east. Eastward, therefore, equals spinward. If north is in front of me, east is to my right. If I stand at the galactic rim with spinward to my right, I'm facing away from the reader. Thus, Galactic North is away from the reader.[/quote']

 

Are you speaking as if looking at the galaxy edge-on or top down?

 

Keith "quick question" Curtis

[BobGreenwade]

Re: Galactic Coordinates

 

Are you speaking as if looking at the galaxy edge-on or top down?

The published galactic map is polar, so "top down" (or "bottom up," or whatever).

[Agemegos]

Re: Galactic Coordinates

 

I would think it would be best to use Spherical Coordinates. So just use another angle. (P, theta, Phi)

 

P = distance

theta = angle along the galatic plain (earth could be 0 degrees)

Phi = the angle above or below the Galactic plain.

 

Spherical co-ordinates have three disadvantages compared with polar co-ordinates.

 

1) They require more trigonometry in distance calculations

 

2) They make it more difficult to locate a point on a polar projection (such as a view of the galaxy from along its axis)

 

3) In the case of the galaxy all the points of interest (stars with habitable planets) are confined to the disk (the central bulge consists of closely-packed red giants, and the halo stars are all low-metallicity Population II stars: neither of which types is capable of shepherding a habitable planet, see http://www.solstation.com/stars.htm). That means that phi will always be a small value.

 

I'd recommmend spherical co-ordinates for a more spherical object such as the core or the halo, but the disk is essentially cylindrical, and polar (cylindrical) co-ordinates will work better.

[Nyrath]

Re: Galactic Coordinates

 

I would think it would be best to use Spherical Coordinates. So just use another angle. (P, theta, Phi)

 

P = distance

theta = angle along the galatic plain (earth could be 0 degrees)

Phi = the angle above or below the Galactic plain.

I believe this was the system used by Isaac Asimov in his novel The Stars Like Dust, with the minor difference that he used "Rho" instead of "P" (and to tell the truth, a lower-cased Rho does look like the letter "P")

 

For galactic north, I vaguely remember that astronomers used the old "right hand" rule, just like the physicists. Curl the fingers of your right hand and stick up your thumb. When your fingers curl in the direction of galactic spin, your thumb points north.