# The Naked Scientists Forum

### Author Topic: Is there already a chart listing the Distances between other Stars near Earth?  (Read 723 times)

#### starman2485

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##### Is there already a chart listing the Distances between other Stars near Earth?
« on: 26/02/2016 19:45:11 »
I'm currently working on a creative project involving space travel. To help streamline the project, I need to look up at a glance the distances between just about all the stars near Earth. In my research, I've found that there are tons of lists of the distances from Earth to the surrounding stars, but there is no easy way to look up the distance between say, Procyon and Epsilon Eridani.

I have already found a website that has a calculator where I can input the Right Ascension, Declination, Magnitude, and Lightyears from Earth of two stars and it will calculate the distance between the two for me. I've used this to start building my own chart, however it has been quite time consuming to input all those numbers each time. I was wondering if anybody knew of any kind of chart like this that already exists that could save me lots of time.

#### chris

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##### Re: Is there already a chart listing the Distances between other Stars near Earth?
« Reply #1 on: 27/02/2016 00:24:38 »
This sounds so simple that I would be very surprised if someone hasn't written a basic algorithm to generate these distances and output them as a series of numbers. Astronomers must have access to systems that will do this, surely?

Failing that, drop the team at Frontiers a line; the galactic map in Elite: Dangerous is accurate and has algorithms to plot routes and distances between stars; they must have solved your problem to build their solution!

#### evan_au

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##### Re: Is there already a chart listing the Distances between other Stars near Earth?
« Reply #2 on: 27/02/2016 03:28:37 »
Quote from: starman2485
I need to look up at a glance the distances between just about all the stars near Earth
From a programmer's perspective, it is inefficient to store a list of distances between stars.

If there are n stars in the catalog, the number of distance entries is n2-n. The Hipparcos catalogue has 118,000 stars, so a table of distances between all these stars would have well over 10 billion entries!

I tried downloading part of the Hipparcos catalog, and it took a long time; downloading one with 14 billion distance entries would be even more painful! (The Gaia satellite is busy creating an even bigger catalog!)

So I suggest that you use a program, which just needs to store the n star entries that you want as 3-dimensional locations in space, and let the program calculate the distances between the stars that you want, at the time that you want them..

Up to and including the 21st century, astronomy has been very much following a Geocentric model, where all locations of stars and galaxies are described relative to the Earth (Right Ascension and Declination). All our telescopes and spacecraft are so close to the Earth and Sun that we have never had a need to do it any other way...

Maybe buying a computer game might be one way to gain access to this pre-existing information, as Chris implied?
« Last Edit: 27/02/2016 03:49:30 by evan_au »

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##### Re: Is there already a chart listing the Distances between other Stars near Earth?
« Reply #2 on: 27/02/2016 03:28:37 »