as most/all distances are guesswork in todays astronomy, any position ingame is guesswork, too.
Newbie Question About Star Positions
- Thread starter Old Duck
- Start date
as most/all distances are guesswork in todays astronomy, any position ingame is guesswork, too.
ED makes me want to take some online astronomy classes. I know we can figure out approximate distances of close stars using parallax created by our own orbit, but how do we know something 1000 light years away is actually that far away? That's a rhetorical question unless someone wants to answer it. Gotta love a game that makes you think!
Ok, for a first, and very interesting, course in astronomy, I'd like to refer you to this old thread here.
Next, Distances to stars... well, before Ziljan notices this and starts to thrash me, physicist are often glad to just get the right order of magnitude. Astrophysicists have to restrict themselves to the right order of magnitude for the exponent
. A bit more seriously: mostly guesswork, yes. Educated guesses, though, and with a combination of guesses you can get pretty close. Parallax measurement only gets you so far, then you'll have to rely on red shift, apparent brightness vs. colour, movement and gravitational models and generally not looking at individual stars but groups of stars. Doesn't matter that much in ED, where a star is where you put it, but if someone (can't remember who it was in this instance) compiles a list of stars from multiple catalogues, and depending on which catalogue you use, that star is either 10 ly or 1000 ly from Earth, things become slightly strange.New question about star positions - when I look at a system on EDSM and it says, "That system has known coordinates," how do I use ED coordinates to find that system in planetarium software like Stellarium? You can search by position in Stellarium, but it gives many options (Galactic, Ecliptic, etc).
Another option would be a tool that tells me the HIP number for a given system.
Here's a very specific example - how do I find the Cubeo System in the night sky IRL (again, using software like Stellarium)?
Another option would be a tool that tells me the HIP number for a given system.
Here's a very specific example - how do I find the Cubeo System in the night sky IRL (again, using software like Stellarium)?
To give co-ordinates to an object in 3-d space, you need three numbers. Exactly what those numbers mean can vary.
For example, the co-ordinate system in the ED starmap is an x-y-z Cartesian system, with all three numbers representing a distance along an axis, with the units all in light-years. However, this kind of system isn't in common use by astronomers in the 21st century, primarily because distances are a major cause for positional error. Instead, astronomers use the "right ascension-declination-distance" co-ordinate system; this gives two angles determining an object's position in the sky, followed by the distance to that object. And all an astronomer usually uses is RA-Dec, since "distance" is largely irrelevant if all you need to really know is where to point your telescope. All of which means, there isn't an easy way to convert ED galactic co-ordinates into something an astronomer would use in a planetarium.
Now, as to your Cubeo question. First, let's look at the information given for another star system. To pick one at random, I chose the Geras system. If you select that system from the galaxy map and open the system map, then select the star on the system map and then look at the star information on the system map, underneath all the usual statistics for a star (age, mass, radius, etc) you'll see down the bottom "Star catalogue information" and a list of catalogue ID numbers (for Geras, there are three: Gliese, HIPP and HD). This means Geras is a real-world star which you can find by looking up those catalogue numbers in SIMBAD or some other star database.
Now try the same for Cubeo. You will see it does not have the "Star Catalogue information" section. This means that Cubeo is not a real-world star. It's a procedurally generated system.
For example, the co-ordinate system in the ED starmap is an x-y-z Cartesian system, with all three numbers representing a distance along an axis, with the units all in light-years. However, this kind of system isn't in common use by astronomers in the 21st century, primarily because distances are a major cause for positional error. Instead, astronomers use the "right ascension-declination-distance" co-ordinate system; this gives two angles determining an object's position in the sky, followed by the distance to that object. And all an astronomer usually uses is RA-Dec, since "distance" is largely irrelevant if all you need to really know is where to point your telescope. All of which means, there isn't an easy way to convert ED galactic co-ordinates into something an astronomer would use in a planetarium.
Now, as to your Cubeo question. First, let's look at the information given for another star system. To pick one at random, I chose the Geras system. If you select that system from the galaxy map and open the system map, then select the star on the system map and then look at the star information on the system map, underneath all the usual statistics for a star (age, mass, radius, etc) you'll see down the bottom "Star catalogue information" and a list of catalogue ID numbers (for Geras, there are three: Gliese, HIPP and HD). This means Geras is a real-world star which you can find by looking up those catalogue numbers in SIMBAD or some other star database.
Now try the same for Cubeo. You will see it does not have the "Star Catalogue information" section. This means that Cubeo is not a real-world star. It's a procedurally generated system.
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Your entire post was interesting, but this especially caught my attention. What you're saying is that there are PG stars in the bubble? I wasn't expecting that. I assumed the bubble would be all cataloged stars...
I'm a PS4 player waiting in agonizing limbo, so I don't have the galaxy map. I'm not seeing this info on EDSM. Are there any 3rd party apps that provide this info?
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There are thousands of PG stars within the bubble. Many are uninhabited brown dwarf systems with standard PG names, like "Perseus Sector YZ-X b2-10". Others, like Cubeo, were nice warm stars with inhabitable planets so they've been colonized.
Imperial space is more likely to have procedurally-generated planets, as it's quite far away from Sol; a typical M, K or even G class star 200 LY away isn't going to be naked-eye visible from Earth and many stars at that range aren't even going to be in the catalogues FD imported. Some stars even closer than that aren't in ED.
Consider the TRAPPIST-1 system, which was in the real-world news a few months ago when they found a whole bunch of terrestrial planets there. People of course immediately went to find the system in-game, only to discover that there were no class M8 red dwarfs at the estimated location of TRAPPIST-1. Purely by chance, however, there was a procedurally-generated brown dwarf system in almost exactly the same position, so FD manually edited that brown dwarf system, changing the star type to M8, the planets to what the TRAPPIST telescope has detected and renaming the system TRAPPIST-1. It's now the closest uninhabited Earth-like planet to Sol; they had to make it uninhabited, otherwise inserting a brand-new high-population Agricultural system there would have messed around with the Powerplay and BGS calculations in that strategic region of space.
But the point to consider is this: TRAPPIST-1 is a red dwarf star only 40 light-years away from Sol, well within the Bubble, yet it wasn't in any of the catalogues FD originally imported into the game. It was a catalogued star, known as 2MASS J23062928-0502285 (just one of several catalogue numbers it was known as); some 2MASS stars were imported into ED, but many were not, including this one.
Imperial space is more likely to have procedurally-generated planets, as it's quite far away from Sol; a typical M, K or even G class star 200 LY away isn't going to be naked-eye visible from Earth and many stars at that range aren't even going to be in the catalogues FD imported. Some stars even closer than that aren't in ED.
Consider the TRAPPIST-1 system, which was in the real-world news a few months ago when they found a whole bunch of terrestrial planets there. People of course immediately went to find the system in-game, only to discover that there were no class M8 red dwarfs at the estimated location of TRAPPIST-1. Purely by chance, however, there was a procedurally-generated brown dwarf system in almost exactly the same position, so FD manually edited that brown dwarf system, changing the star type to M8, the planets to what the TRAPPIST telescope has detected and renaming the system TRAPPIST-1. It's now the closest uninhabited Earth-like planet to Sol; they had to make it uninhabited, otherwise inserting a brand-new high-population Agricultural system there would have messed around with the Powerplay and BGS calculations in that strategic region of space.
But the point to consider is this: TRAPPIST-1 is a red dwarf star only 40 light-years away from Sol, well within the Bubble, yet it wasn't in any of the catalogues FD originally imported into the game. It was a catalogued star, known as 2MASS J23062928-0502285 (just one of several catalogue numbers it was known as); some 2MASS stars were imported into ED, but many were not, including this one.
Forgive my very fundamental grasp of astronomy (I'm more of a star gazer than amateur astronomer), but is it safe to assume there are cataloged stars outside the bubble? You know, the huge, bright stars we can see with our naked eye even though they are many hundreds of light years away?
Yes, there are plenty of those too. Particularly bright stars, well known nebulae, some odd looking tubes of stars (those are an artefact of surveys looking at a small area of the sky in great detail) and some that are only bright if you're looking with a radio telescope rather than an eye. I seem to remember reading that there are best part of 200k stars from existing catalogues, I want to say ~160k - although I could be making that up.
Sagittarius A* (the super massive black hole at the heart of the galaxy) is the farthest away real star in game at about 26,000ly - not least because we can't really see much detail beyond it from here because the core's in the way...