Astronomy Basics - How do I figure out star distances

[Engineer Doramos]

Here's a fun puzzle I'm having to deal with as I make a realistic star travel campaign setting. I've managed to find a list of all the yellow-orange stars within 100 light years of earth, and most of them up to about 50 light years have enough data on them that you can tell if they might possibly have a rocky planet in the water zone that would generate life. The rest, Im just guessing based on feel. I know the distance each is from earth and what constellation they are in or near, but I don't know how to figure how far they are from each other. There is a planetarium with an observatory in my home city, I was wondering about asking them, but there are lots and lots of potentially habitable planets. Hmmmm. Anyone have any resources on this, where I can determine one star's distance from another if I have the names of the stars?

[Greylond]

Try this page;
http://curious.astro.cornell.edu/question.php?number=302

[nijineko]

short of looking it up in a resource of some kind... it's a matter of plotting on a 3 dimensional grid where each planet is in relation to each other and then doing some fancy footwork with the pythagorean theorem. and that's assuming a still snapshot not taking into account movement within the galactic arm. ^^

[Engineer Doramos]

Try this page;
http://curious.astro.cornell.edu/question.php?number=302

Cool, thanks Greylond! Ugh, thats a lot of math I have to do. Not even sure if my mac can look up sines and cosines, and I haven't had a scientific calculator in a long time.


At least I don't have to use the equations at the bottom of the linked math page. ><


I'm also not sure where in all the data I have the RA and DEC are, but I might find it there... if not I search elsewhere.


I already have 72 planets and I'm somewhere between 70 and 80 light years out. You can see there's a massive amount of work I have to do.

[Edit] After pondering the sheer logistics of trying to keep track of all the distances between hundreds of planets, I'm going to have to try another tactic. I still need to find out their general locations to one another however, especially to figure out history bits.

[Lev Lafayette]

Distance between stars? Find the x, y and z axes.

Distance^2 = (x1 - x2)^2 + (y1 - y2)^2 + (z1 - z2)^2

[Engineer Doramos]

The problem is more like tying to group stars into sectors. If I have to work on a math equation on how far each star is from one another using Earth as an extrapolation every time, even if manage to get all the angles, it will be too clunky. If I try and predetermine all that data for the setting, I will go bonkers and lose my head of hair from pulling it all out. I figure since I have the constellations and the distance, I can eyeball it into some kind of 3-D sectors. There is also a page for each of the more known stars which tells me what stars are nearby, so that will help form sectors. I will still need to know the distance from one sector to nearby sectors though. Guess I need to look up a map of the constellations.

[Skunkape]

Distance between stars? Find the x, y and z axes.

Distance^2 = (x1 - x2)^2 + (y1 - y2)^2 + (z1 - z2)^2

I'm with Lev Lafayette on this one. It's not going to be realistic, but figuring out the x, y and z coordinates based on Earth being at 0,0,0, you can then use the above formula to get distance from any two stars. For a game, that's more than accurate enough for me.

[Greylond]

If you can find it the old rpg Traveller 2300 had a map just like this.

[Skunkape]

If you can find it the old rpg Traveller 2300 had a map just like this.

LOL, that's what I was actually thinking of when I mentioned the x,y,z coordinate system above!:)

[Greylond]

Yea, I wish I still had that game...

[Engineer Doramos]

Excuse me, but its been a long time since math class for me. But in my understanding of geometry, you need to know two sides and the angle between them to come up with the length of the third side. As for D squared = X squared + Y squared + Z squared, I dont have D or Z so I cannot solve that with the information I currently have. I don't have coordinates of the stars, just two angles from the earth's surface by which to measure them, and the distance, so it will take Greylond's method to find it out, which is to use sines and cosines. Now, as for Traveller - the coordinates they give might be helpful, but I'm not sure if they have the same planets marked. I guess I would have to see if I can find a copy.

Right now, I have them grouped into 4 north quadrants and 4 south quadrants, with the astrological signs they are near noted, along with the distance from Sol. I may just want to eyeball distances at this point, it won't be totally accurate but I don't think people will lynch me for it. Starships can only jump so far before they need to replace something in their cores anyway, so I shouldn't need to plot out how long it takes to jump from one end of a quadrant to the other end of an opposite quadrant.

[spotlight]

The old X^2 + Y^2 + Z^2 formula is always the way to go. The sines and cosines you mentioned before are nessasary to set the three co-ordinates to begin with. Once you have those coordinates set (in stone, so to speak) then your game is ready to go. I have seen grid maps of 3D games before, and enjoyed some, and the designer always goes thru the trouble and work setting up these X,Y,Z things before hand. The formula is only for determining the straght line distance a ship must travel.

BTW, I have done it myself in years gone by, and getting those coordinates set is A LOT OF WORK. So, don't envy my failer to finish the project. Getting the real time positions of the stars is a bunch more than I ever did. More power to you.

[Engineer Doramos]

I'm still thinking eyeballing it works best for now, as I have a lot of other things to cover. However, I am really grateful for the help and pep talks. I think the two big deciding factors are 1) I dont have the energy to do all that math and 2) I don't have all the data needed for the RA and DEC of every star so I would have to search more, and some of these stars are quite obscure. I guess what I was really looking for was a genie to tell me of some website that is like babel fish with interstellar distances lol.

[nijineko]

now you know why the sgf-1 stargate has a dial-a-planet approach! ^^ try explaining all that math on tv. =D

as far as a list goes, try this link with a handy map. http://en.wikipedia.org/wiki/List_of_nearest_stars

pretty useful. in my opinion, your best bet is to simply plot them yourself on a x-y-z grid, using whatever arbitrary units you feel like. that way you can set the centerpoint of 0,0,0 to whatever star you want, or even no star at all. then simply state how many units each star is away from that center point. then if you really want to, you can use the formulas given above to calculate exact distances between each other.

even simpler than that, just eyeball it and blame any variance on the vageries of your medium of travel. in this case, close enough is good enough. (just don't let the astrogators know that!) ^^

[Greylond]

I found a copy of the Traveler 2300 list and sent it to him. Hope it helps out...

[Engineer Doramos]

Holy Death Rays! That Traveller thing was way more useful than I was expecting! Thanks a million Greylond. It was a games workshop chart compiled from an actual star catalog, complete with x y and z vectors based in light years. Now I just have to find my chosen planets. Stupid mac can't even do square roots heh, maybe I need a widget for that. Let's see, according to google calculator, I got 16.1 light years to Eta Cassiopiae with them, and my reference says its 19.4. Could be drift, since theirs is based off 1969 data, and mine is probably more recent information. I'll monkey with the positions a bit to reflect that its 2150 ad. Thanks for the encouragement everyone! And yeah, Ninjineko, I was thinking a lot about the whole stargate thing a lot because I'm a fan of Fading Suns, which uses jumpgates left behind by elder aliens. I just wanted a free-cruising space system, where you could go anywhere. Eventually I found I had to place limits on it in order to make it playable, but I'm really happy with this new data! It will help make it so much easier to allow more player freedom (if they ever can afford a ship).

[Edit] Ohh! I just thought - While I will have relay space stations on non life supporting star systems and in deep space, I now need a random encounter table for people who hyperjump to unknown regions of space. *Laughs evilly*

[Skunkape]

Holy Death Rays! That Traveller thing was way more useful than I was expecting! Thanks a million Greylond. It was a games workshop chart compiled from an actual star catalog, complete with x y and z vectors based in light years. Now I just have to find my chosen planets. Stupid mac can't even do square roots heh, maybe I need a widget for that. Let's see, according to google calculator, I got 16.1 light years to Eta Cassiopiae with them, and my reference says its 19.4. Could be drift, since theirs is based off 1969 data, and mine is probably more recent information. I'll monkey with the positions a bit to reflect that its 2150 ad. Thanks for the encouragement everyone! And yeah, Ninjineko, I was thinking a lot about the whole stargate thing a lot because I'm a fan of Fading Suns, which uses jumpgates left behind by elder aliens. I just wanted a free-cruising space system, where you could go anywhere. Eventually I found I had to place limits on it in order to make it playable, but I'm really happy with this new data! It will help make it so much easier to allow more player freedom (if they ever can afford a ship).

[Edit] Ohh! I just thought - While I will have relay space stations on non life supporting star systems and in deep space, I now need a random encounter table for people who hyperjump to unknown regions of space. *Laughs evilly*

I used that chart to find the coordinates of the nearest stars within a 21 light year radius! Course, I didn't bother to worry about drift as the data was fine for me.

About 18 years ago, I had a Mac program that let you use an Excel spreadsheet to give it a coordinate system and it would display a pseudo 3d map of those coordinates on the screen. Can't remember the name but I'm sure that there's got to be programs that will do the same.

Somewhere I have a link for a newer program that does star mapping, but I couldn't find it so I'll have to keep looking and post it if I do find it.

[Moritz]

http://shop.nationalgeographic.com/product/179/42/123.html

Here's the maps I use.

[nijineko]

Stupid mac can't even do square roots heh, maybe I need a widget for that.

there are any number of free scientific calculators for download. try apple downloads first, then google it if you still aren't happy.


I used that chart to find the coordinates of the nearest stars within a 21 light year radius! Course, I didn't bother to worry about drift as the data was fine for me.

copy for me too, please?

[Skunkape]

copy for me too, please?

Found this on the web, it's not the link to the application, got to fire up my old computer for that and then find the link in my favorites, but I've got to hook up a network cable to it first. I'll try and make sure to do that tonight when I get home.

Anyway, found a revised version of the near star list for 2300 at the following link (http://www.caco.demon.co.uk/2300ad/NearStar.html).

The main page that the list is on is here (http://www.caco.demon.co.uk/2300ad/2300ad.html). I need to take some time to look this page over, looks like it's got some good resources listed on it.

[nijineko]

thank you kindly! i'll try to recall to bookmark those once i get home. ^^

[Skunkape]

Finally found the website with the star mapping software. I don't own this yet, but thought it was interesting and am interested in buying it.

Nbos Software (http://www.nbos.com/)

[Arch Lich Thoth-Amon]

Very cool, indeed. Me, being a fellow Traveller enthusiast, anything Traveller is cool. Cant ever have enough of a good thing, i always say.

[Edward]

I wonder if Celestia (http://www.shatters.net/celestia/) would do what you need. I know people use it for sci-fi games, and it's a free program. You might want to try posting on their forum.

If Celestia itself doesn't have the functionality you need, one of its add-ons might.

[Moritz]

Ed,
This is the sweetest thing ever.

[nijineko]

thank you for the links. there are a few free planetarium programs for the mac that i've tried. interesting stuff. i'll enjoy looking through these when i have the time. ^^

[Edward]

This is the sweetest thing ever.

Have you used it for one of your games? I've just played around with it a little so far, though I've thought about using it as a game aid.


thank you for the links. there are a few free planetarium programs for the mac that i've tried. interesting stuff. i'll enjoy looking through these when i have the time. ^^

Celestia is different from a planetarium program, because your perspective doesn't have to be from Earth. You can travel around to different points in space.

[nijineko]

heh. silly me. i just checked and celestia is one of the mac programs i was speaking of. i haven't used it in a long while.

[boulet]

Anyone knows of a list of detected extra-solar planets somewhere ?

[Edward]

Check out http://www.extrasolar.net.

I found the link in the Celestia forums (http://www.shatters.net/forum/index.php). You might want to poke around there a bit; there's some discussion of extrasolar planets. Search on extrasolar and exosolar.

[boulet]

Thanks Edward !

[Razmus]

http://shop.nationalgeographic.com/product/179/42/123.html

Here's the maps I use.
I've been rather enamoured of this one lately:
http://www.projectrho.com/smap12.html#map03
although this one looks pretty nice too:
http://www.projectrho.com/smap12.html#map02

[Razmus]

Finally found the website with the star mapping software. I don't own this yet, but thought it was interesting and am interested in buying it.

Nbos Software (http://www.nbos.com/)

Anyone use AstroSynthesis (http://www.nbos.com/products/astro/astro.htm) from NBOS and willing to comment on it?

[Skunkape]

Anyone use AstroSynthesis (http://www.nbos.com/products/astro/astro.htm) from NBOS and willing to comment on it?

Haven't purchased it yet. Still want to, but haven't had the extra funds.:(