[Stellar Mapping] The 2300AD Near Star Map

The 2300AD Near Star Map

The 2300AD RPG – originally published by Game Designer’s Workshop in 1988 – presented an excellent gritty, realistic near-future hard sci-fi setting with lots of exploration, mystery, and interesting aliens. It’s also about to be republished by Mongoose Publishing as a setting for their version of the Traveller RPG!

One of 2300AD’s most interesting features is that the setting is built around a realistic (for the 1980s) Near Star List based on the Gliese Catalogue (2nd Version). FTL travel in 2300AD has a maximum range of 7.7 lightyears, resulting in the creation of “Arms” that extend from Sol to connect only the stars that are within this range of eachother (this limit can potentially be extended to 11.55 ly using Stutterwarp tugs, but this is expensive and uncommon).

There are three of these Arms, each colonised by a different political power in the setting – the French Arm, the Chinese Arm, and the American Arm. The French Arm stretches “upwards” from Sol towards Galactic North, ending at the orange giant star Arcturus. The American and Chinese Arms share the same beginning, but split off so that the American Arm heads Coreward/Spinward while the Chinese Arm sprawls around the (galactic) southern part of the solar neighbourhood.

Unfortunately the Near Star List (NSL) has not been updated for the new version of 2300AD. A lot of stars have been discovered in the solar neighbourhood since the late 1980s (as shown on my Stellar Mapping page), and the locations and distances of existing stars have been greatly refined since then too – so how does the updated stellar data affect the Arms?

Quite significantly, it seems. Here’s a overview (made in Astrosynthesis) showing all of the Arms plotted on an accurate starmap consisting of the RECONS, DENSE and Hipparcos stars within 50 lightyears.

2300AD Arms

The French, Chinese, and American Arms of 2300AD (coreward is to the right).

The systems with yellow labels are on the French Arm (routes are cyan), the ones with red labels are on the Chinese arm (routes are green), and the ones with green labels are on the American Arm (routes are white). The yellow dashed lines represent routes between two stars that were closer than 7.7 ly in the original NSL, but are actually more than 7.7 ly apart in the modern data. The red dashed lines represent routes that require connecting stars that don’t exist. As you can see, there are quite a few yellow dotted lines…

Next, we’ll look at the individual Arms in more detail and see where the problems lie.


The American Arm

The American Arm (3D view)

The American Arm (2D Map)

Extending roughly Coreward from Sol, the American Arm contains five “broken links” that are longer than 7.7 ly.

– The broken link between Serurier (Ross 154) and Broward (Wolf 1061) is problematic, since there are no stars between the two that can connect them directly, and since both stars are close to Sol is unlikely that any have yet to be discovered in that region. Instead, the shortest way to connect them is via a circuitous route that goes from Ross 154 (Serurier) to AX Microscopii to SCR 1845-635 to Gliese 682 (Davout) to 36 Ophiuchi (DM -26 12026) to Wolf 1061 (Broward).
– The HIP 86287 (New Melbourne) to HIP 83762 (Ross 863) route is also troublesome, since there are no known connecting stars and the gap is particularly wide at 17.8 ly (which precludes stutterwarp tugs as a solution). Both systems are beyond the RECONS 22.8 ly sphere, which opens the possibility that there may be undiscovered objects out there – this means that fictional M dwarfs or brown dwarfs can be added to connect the two systems, though the length and geometry of the gap requires at least three such fictional objects.
– HIP 83762 (Ross 863) to HIP 82003 (Botany Bay) is another wide gap of 14.3 ly. In this case however, it is possible to connect from Ross 863 to HIP 84794 (Gliese 669) to HIP 83043 (Gliese 649) and then to Zeta Herculis (Kingsland). Gliese 669 also itself connects to Zeta Herculis.
– Gliese 667 (DM -34 11626) can connect to HIP 84720 (DM -46 11370) via HIP 80018. Incidentally, Gliese 667 is known to have planets around it!
– Gliese 661 (Red Speck) can connect to Alpha Lyrae (Vega) via 2MASS 1835+325.


The Chinese Arm

The Chinese Arm (3D View)

The Chinese Arm (2D Map)

The Chinese Arm covers much of the solar neighbourhood “below” Sol (towards Galactic South), and includes several well-known stars. Officially, it begins at Delta Pavonis, which is reachable from Gliese 682 (Davout) on the American Arm. There are several broken links/points of interest on this Arm:

– The Delta Pavonis to Gliese 682 (Davout) link is broken, but they can connect via Gliese 693.
– The link between Gliese 832 (Xiuning) and Gliese 1 (Hunjiang) is broken, but the stars can connect via Epsilon Indi.
– “Rho Eridani” is actually two unrelated stars (Rho 1 and Rho 2) that are both hundreds of lightyears from Sol – the star in its place is actually “p Eridani”. Evidently, the authors of the original map misread the lower-case “p” and thought it was a greek lower-case “rho” (&#961), and this error was propagated in later editions.
– The Delta Pavonis to Beta Hydri and the p Eridani to 82 Eridani links are broken, which means that they (and Zeta Tucanae) are isolated from the rest of the Arm. There are no known stars able to connect them to the Arm – fictional red/brown dwarfs or stutterwarp tugs would be required.
– Although there are no known stars between p Eridani and 82 Eridani, 82 Eridani can be reached from Tau Ceti (and Epsilon Eridani) by going to Gliese 1061, then to DEN 0255-470 and then to 82 Eridani.
– Ross 780 (DM -15 6290) and Gliese 908 (DM +1 4774) are separated by 7.71 lightyears, which is [i]just[/i] over the stutterwarp range limit (by a mere 600 AU or so). This could be handwaved away as being within the operational tolerances of the stutterwarp drive, or an alternate route between the two systems via either Gliese 1002 or Gliese 1005 can be used instead.
– The DM +20 5046 (Doris) system is a fictional system that does not exist – in fact, the EQ Pegasi/Ross671 finger is a dead end. A K5 V primary seems a little bright to be unknown at this distance from Sol, which makes it hard to justify this star’s existence in this location. The closest system not on the Arm is Ross 775 (a close M V binary pair, unlikely to have a habitable world around them), which is 7.98 lightyears from Ross 671. The best solution is probably to relocate Doris’ worlds to Gliese 1002, which is a solo M V star (incidentally, Kanata – Doris’ mainworld – should be tidally locked to its star in either case).
– Qinyuan is not shown on major route on the Chinese Arm, but it is located in the UV/BL Ceti system.


The French Arm

The French Arm (3D View)

The French Arm (2D Map)

The French Arm extends “upwards” from Sol towards Galactic North, ending at Arcturus (Alpha Bootis). It is the most problematic of the Arms, containing several broken links and four systems that do not exist.

– The link between Sol and Wolf 359 (Nyotekundu) is broken since Wolf 359 is actually 7.78 lightyears from Sol, so we’re off to a flying start! Fortunately there is a newly discovered brown dwarf binary system (WISE J1049-5319, a.k.a Luhman 16) that can bridge the gap between the two.
– the link from Lalande 21185 (Bessieres) to Gliese 380 (Neubayern) is also broken. The stars that connect the two result in a somewhat circuitous route, going from Lalande 21185 to DX Cancri to Gliese 388 to 2MASS 0937+293 to Gliese 380. A brown dwarf directly between the two stars would also be a viable alternative, however.
– Queen Alice’s Star and Kimanjano are both fictional systems that are required to connect Gliese 412 (Augereau) to Beta Canum Venaticorum and Beta Comae Berenices (Nous Voila). There is an alternate route to Beta Canum that involves travelling from Gliese 412 to Gliese 388 to Ross 104 to Xi Ursae Majoris (the somewhat misleadingly named “Kie-Yuma”) to HIP 57802 (DM +36 2219) to Beta Canum – the worlds of Queen Alice’s Star and/or Kimanjano could be relocated to one of the stars on this route. However, there is no alternate route between Gliese 412 and Beta Comae Berenices, so it may be better to use Queen Alice’s Star and Kimajano for that purpose since fictional systems would be required to connect them.
– Berthier is a fictional system connecting 61 Ursae Majoris (Joi) and Beta Canum – it could have been intended to be Gliese 438.1, but this is actually an orange giant located over a thousand lightyears from Sol. This system is likely to be HIP 57050 – an M4 V star that is accessible from HIP 57939 (see below) and connects to 61 Ursae Majoris (HIP 57050 also is known to have a planetary companion).
– the 2300AD maps are somewhat ambiguous, and it could be that Henry’s Star (Crater) actually connects 61 Ursae Majoris to Beta Canum instead of Berthier. Henry’s Star is HIP 57939 (a.k.a. Gliese 451 or Groombridge 1830) – this is a metal-poor G8 VI subdwarf star that is known to “superflare”, so it wouldn’t be a good place for a habitable planet at all. That said, Crater isn’t all that habitable anyway, and as luck would have it the 2300AD Colonial Atlas mentions that Crater is regularly bombarded by flares from a companion star that is now known not to exist, so this works out pretty well!
– the link between Beta Comae Berenices and HIP 66459 (DM +36 2393) is broken, but HIP 66906 can be used to connect them.
– the link between HIP 66459 (DM +36 2393) and HIP 67422 (Hochbaden) is broken, and there are no known connecting stars. These are far enough from Sol that a fictional brown or red dwarf could be added to connect them though.
– the link between HIP 67422 (Hochbaden) and Eta Bootis (Aurore) is broken, but WD 1345+238 (a white dwarf from the DENSE catalogue) can be used to connect them. This also connects to Alpha Bootis (Arcturus).
– Gamma Serpentis (the Käfer homeworld) does still connect to Arcturus via HIP 75187 and HIP 72848.
– Vogelheim is a fictional system. It could be replaced by HIP 54646, which is the next star out from HIP 57087, towards Pentapod Space.
– the Bayern Corridor is described (in 2320AD) as being along the route to the Pentapod Homeworld (which is past HIP 57087). However, this would have been an extremely circuitous route for the Bayern to take to the Pleiades – a much more direct route would be to leave the Solar Neighbourhood from the vicinity of Omicron 2 Eridani on the Chinese Arm.



It is possible to squeeze the existing Arms into the realistic star map, but the significant problems with the French Arm reveal the proverbial elephant in the room, which is that the Arms do not follow the “natural flow” of the actual 7.7 ly routes between the stars – instead they leap across gaps that separate them. This is illustrated nicely at Sol itself – the only way to reach the surrounding stars from Sol (while remaining within the 7.7 ly limit) is to travel from Sol to Barnard’s Star to Ross 154 (Serurier) to AX Microscopii, from which one can join a web-like network of systems that extends in several directions. However, 2300AD has the French Arm leaping a gap to Wolf 359, and neither the American nor Chinese Arm go to AX Microscopii at all and leap to Wolf 1061 instead!

The animation below shows the real network of 7.7 ly links around Sol, along with the 2300AD Arms. The “real” network is shown as the grey links between stars (expand the video to full size to see the detail). This significantly changes the astrography of the setting, and will be discussed in subsequent posts.

Animation of realistic 2300AD links

Next article: Realistic Near Star Map Project – Introduction

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10 Responses to “[Stellar Mapping] The 2300AD Near Star Map”

  • Fascinating read! I’m also impressed that a sc-fi rpg would engender such need to be ‘accurate’ in its star map (which of course is part of its charm). As the person who drew the star map for the new edition I can confirm that it hasn’t changed at all. Understandably so.

  • Yeah, it’s a shame that it hasn’t been updated (then again, this is largely down to bad timing). At least with this (and the next article on the subject that I’m going to write, which will examine the real network I mention at the end of this one in more detail), someone can make their own 2300AD games more realistic if they want to.

  • An excellent article. It is tempting to update the 2300AD Near Star Map to retain its original perceived accuracy, but it’s not really possible. Moving stars and planets around breaks too much else in the setting. It’s like deciding Carthage makes more sense on Sicily than in Northern Africa.

    A question I throw out in case anyone is more motivated than I am to dig through the original material is if GDW ignored any connections known at the time in favour of fictional systems. If I remember correctly, in the Challenge articles about the original map, the designers admitted to nudging Nyotekundu to open up the French Arm.

    • I’m not so sure… after all, one K or M V star is pretty much like any other (that said, there seem to be an awful lot of planets that aren’t tidelocked to their stars that should be…). I’d like to try to keep any moved systems on the same Arm at least though.

      I don’t know if the designers tweaked the map a bit. Certainly Wolf 359 (Nyotekundu) should be too far to reach from Sol, but pretty much the entire French Arm is broken really. As for ignoring known connections, there are actually a lot of “minor routes” that are shown in the back of the 2300AD Directors Guide that I didn’t show here – to an extent that seems to reflect the weblike network of stars that you can see in the animation that AX Microscopii allows access to. That’s something I want to look at in more detail in a future article.

  • Very good maps. I still miss your presence over at SJGames. Any chance of getting the reworked arms in a format that is printable on a standard 8 x 11 page. I’m thinking of using the real world data to augment that 2300AD stuff. I’m going to chalk it up to an AGRA created pocket universe (think Grandfather from Traveller) that seeps into the 2300AD universe. This will play havoc with astropolitics, mess up the arms and open more star systems to customized planetary systems. Looking forwards to future updates.


    • Thanks! I should be posting a big update to the stellar datasets this weekend, after which I will hopefully be able to actually get on with sorting out the reworked Arms.
      The printing format is limited to what Astrosynthesis can produce – the most appropriate format for your purposes is a map on a white background like the one at the bottom of the Stellar Mapping page, which I should be able to produce (not sure how great it would look crammed onto a single page though).
      (Also, I’m still active on the SJG forums as Malenfant, I’m just not on the JTAS boards).

  • Most excellent Doctor G, I seem to recall hearing that GDW *intentionally* included a few bogus stars so as to know if someone ripped off their hard work on the 3D starmap. If someone stole it wholesale and didn’t know there were ‘hidden mines’ in it, it would be pretty easy to prove the theft since some do not line up with even data available at that time.

    That may well explain the imaginary systems.

    What would be interesting would be to create an updated map that tried to not take liberties with known star data (or likely to be discovered) and that salvaged as much of the Colonial Atlas material as possible. One would have to accept some changes, but creating something sensible that could work using actual refined distances would be pretty wonderful.

    I’m guessing you used Astrosynthesis for some of the above graphics. Do you have a sector file that you used during the production that you’d care to share?

    Nice work, BTW. Have bookmarked this site!

    • That’s possible, but I suspect that they included those systems simply because they needed to join up some real stars to make the Arms that they wanted. If it made the map unique, then all the better for them I guess 🙂

      I’m actually working on figuring out some new Arms that only use links that are shorter than 7.7 ly, and so far there are a lot of stars that can be reached like that – I’ve got many Arms going out in pretty much every direction. Most of those Arms end around 60 ly from Sol because the dimmer stars that can be used to connect them haven’t been discovered yet, but it goes to show that there are still plenty of systems that are accessible to normal stutterwarp (and also, to answer your other question, that the routing is still interesting at 7.7 ly).

  • Another interesting question would be:

    If SW didn’t stick at 7.7 and 11.5, can you make better sense of the routing? That is to say, if you selected a different ‘magic number’ for the SW distance, will that remedy some of the connectivity issues without rendering other routes senseless?

  • It struck me very early on that the 7.7 ly limit produced a very similar astrography to the one in Jerry Pournelle’s CoDominium/Empire of Man universe: Interstellar travel is limited to a web of usable routes. The designers admitted they chose 7.7 ly after fooling around with their 3-D map of local space simply to limit travel from any one system to only a few others.

    The easiest solution if you want to stick to the canon is to say: “This is the way this universe is” and go on from there.

    If you want go by Dr. Pournelle’s route, it allows for occasional longer jumps but also makes for more effective system defense: If you can maintain fleets at the jump points into a system, you can ambush ships coming through because they have to come through more or less one at a time, and the jump confuses both people and computers. If you aren’t concerned with going through the point yourself, you can mine it, like the Federation did at the Deep Space Nine wormhole to cut off the Dominion.

    Pournelle’s universe requires different drives for jumping and for travel in normal space, sort of like…Traveller, which came out a few years after Pournelle’s stories began to be published. But stutterwarp might allow jumps as a free bonus; it is functionally the same as the “Ion Engines” used in the “Starfire” series of games and novels.

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