Question about Space

[dunmurderin]

Does anybody know how to figure out the distances between stars that aren't the Sun? Like, I want to know the distance between, say, Barnard's Star and HIP 76976 (aka the Methuselah Star). Actually, what I'd like to be able to do is create one of those distance charts like you see in a road atlas, showing how far it is to drive from Chicago to Albequerque or New York to Miami, that kind of thing.

I've found some information online, including a couple of calculators and I've got enough information to begin making some speculative ideas for some worldbuilding I'm doing, but I'd like a nice, easy to read and expandable spreadsheet. I found some sources that give a mathematical formula for doing it but I cannot make my data come out right (this might be a user-interface problem because this is spherical trigonometry and I barely passed college algebra).

I'm specifically looking for stars that are within 190 light-years of Earth because I'm trying to create an interstellar empire of sorts. If you can explain the math to me, please put it in the most basic terms possible. Like, explain it to me like I'm five kinda thing.

These are my sources:

http://fmwriters.com/Visionback/Issue14/wbputtingstars.htm

https://worldbuilding.stackexchange.com/questions/148584/how-can-i-measure-the-distance-between-two-stars#:~:text=The%20unit%20for%20the%20distance,the%20angle%20between%20the%20stars.

http://www.neoprogrammics.com/stars/distance_between_two_stars/index.php

https://www.wolframalpha.com/widgets/view.jsp?id=1ece06643e87f3c4d90813af5ee12223

ALSO: I'd like a reliable source for the ages of various stars because I need stars that are at least as old as the Sun, but preferably older.

Comments

[unavee]

Not sure if this is helpful for creating your spreadsheet. But looking at the first and third links you posted, it seems like you want to convert from "this is how far the star is from Earth" (in spherical coordinates; like latitude, longitude, and distance away) to "this is the distance between two stars" (in light years). And the easiest way to do that is to convert the spherical coordinates to a cartesian coordinate system (as if everything was located in a big box grid; X, Y, Z) so you can use geometry to calculate the distance.

(A note about using cos() and sin() in spreadsheets--you might need to convert degrees to radians, depending on the software you're using?)

[dunmurderin]

Thank you for your reply, sorry for taking this long to get back to you - I posed that question at a point where my sleep schedule for the week went Coco-Bananas.

I went back and converted degrees to radians and that gave me figures that match up with the examples in the first link (Putting Your Stars In Their Places) but with one hiccup: when I go to do the last formula, where you're doing:

Distance2 = (X1 - X2)2 + (Y1 - Y2)2 + (Z1 - Z2)2

(Edit: OR)

Distance = SQRT((X1 - X2)2 + (Y1 - Y2)2 + (Z1 - Z2)2)

I get a figure that doesn't match up with the results the author got. The author got a result of 60.991494 light-years and I got a result of 45.65. Do you have any idea what I might be doing wrong? I can send you a copy of the spreadsheet I've created since that might be more helpful.

Thank you again for your time and consideration, if nothing else, you've gotten me further along than I was!

[unavee]

Sure, I can take a look at the spreadsheet if you want. I'm glad you were able to make some progress!

[dunmurderin]

Awesome! where's the best place to send it?

[unavee]

If you have a link, feel free to send that, or you can email it to my user name at gmail.

[dunmurderin]

I sent it to your gmail and thanks in advance!