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The Eridani Sector: the start of a new 40K campaign setting

Regular readers may recall that all the gaming we Bunker dwellers do in the 40K mythos is set in a lovingly crafted region of space we refer to as the Achernar Sector. Every campaign, and sometimes individual games, leave their mark on the setting and help it grow.

There was just one problem.

A setting initially designed for roleplaying as Inquisition agents (the Cetus sub-sector) and contemplative space exploration (the Scyrian Expanse) doesn't lend itself to big, sweeping wars of the sort one would, on occasion, like to fight. Even fighting big wars in the other two sub-sectors in Achernar would have had too drastic an effect, so we ended up limiting our campaigns to single system affairs, and that's not ideal. One's own setting shouldn't feel constraining.

I am not a subtle creature, and thus my solution wasn't subtle either: create a whole new sector of space next to the current one, with the explicit intention of making it suitable for bigger, explodier wars.

To support this endeavour, my long-serving accomplice Tom and I have been hard at work for the last few weeks (months, technically) trying to create the resources that will be used by the rest of our gaming group and, perhaps, by you too. Naturally, this involved making a map.


Of course a map in and of itself is just a starting point; we've also written a bunch of initial broad brush strokes to get the lore ball rolling. This post is therefore going to cover the following:
  • The new map we made, and some pointers on making your own in Photoshop.
  • The substantial update we've carried out on our campaign wiki.
  • The ten thousand foot view of the Eridani Sector
  • The new map/diagram I made of the Cobalt Scions' new home system.

The New Sector Map

Making the background art

Making a map of something is my favourite way of coming up with the first few details of a thing. The process of just making up an image gives you a bunch of starting points to extrapolate from. What might that dark, dusty area be? What about that nebula, or that empty region? Who lives there, if anyone?

To ask those questions you need to have made the art, so let's talk about that. The illustration beneath the map started out as random splodges of colour over a procedurally generated starfield by adapting the technique shown in this very helpful Photoshop video tutorial.

The technique in that video is suitable for making low resolution images, so I had to fiddle around, at length, to get the initial noise filter and cloud generation to work at the massive resolution that the map file runs at (the finished Photoshop file is 1.4 gigabytes). Why so big? Partially because it's easier to add crisp detail at higher resolutions, and partially so that this thing can be printed (if I ever print it) without pixelating horribly.

Because I am a scrub, this was made using Photoshop CS2: the legacy version of Photoshop that Adobe let you use for free because it's so old it's obsolete.

Despite my limited skills and tools, the new Eridani map was immediately looking a lot nicer than the original map I made for the Achernar Sector. I don't think I even hesitated before I decided to replace the original art I'd slaved over. From that point on I just worked on Achernar and Eridani as one huge image to ensure consistency, and so that the art on the two separate maps would line up perfectly.

Naturally, immersion demanded that the new art for Achernar be somewhat faithful to its predecessor, just... amped up.

Out with the old...

...and in with the new.

Going beyond the Photoshop techniques in the video

Adding more stars in a variety of colours
This was done by drawing drawing tiny dots/circles for the stars, duplicating them, applying a gaussian blur to create a glow, and modifying the hue to create different colours. I'd also use the transform tool to make a variety of sizes. Once I had enough variety, I'd duplicate the layer(s) again and again, spreading them out and rearranging/rotating them until there was no obvious pattern, and then merging it all back down into a single layer because trust me, when you're working on a big file, you want to be organised about your layers right from the beginning or you'll get confused. If it has to be on separate layers, name those layers and keep them organised in folders.

Adding finer detail to the dust clouds/nebulae
The technique in the video is great if you're after some early 90s Star Trek-looking space, but real nebulae have way more definition than that. Now I'm not a pro illustrator, so I was never going to make something look real, but I could make it look more detailed at least.

With photos of real nebulae on my backup monitor, I set about zooming right in and creating more definition and highlights. I'd sketch the shapes I wanted with the brush tool, then use the smudge tool to get smoother fades and shapes, then finally fiddle with the layer's opacity until I was happy with how it looked. The same technique was used to add further definition to the dark dust clouds. Here's a step by step so you can see the different elements building up:

Since the original image is absurdly high res, you could cut out smaller sections of it and use it for yourself. Here's a link for the full resolution art. It's 109x37cm, or 43"x15", give or take, at 300DPI.

Standard legalese applies if you actually wish to use this background art for anything; it's copyright me, naturally. I realise it's presumptuous to assume anyone would actually want to use it, but: I do not give permission for this image to be used for profit without my explicit consent. If you want to use it for anything not profit related (which seems like the less unlikely scenario) then go ahead. Just drop a comment here on the blog and let me know! Not because you have to, just because I'm curious and it'll bring me joy. Also if you linked back to the Beard Bunker that'd be great, but I ain't the boss of you.

Here are some closeups at 50% resolution, because woo! Bright colours.

Names Workshop: putting labels on it

The worst thing about making a map is that you will inevitably have to name some stuff. This usually ends up being a mix of historical references and slinging stuff through Google Translate, then whacking some syllables with a mallet so that it's not just a word in a foreign language.

I did at least have the luxury of a starting point. The idea was that the Cobalt Scions would feel like Rome's first conquests in the Mediterranean, so their home system of Thonis would be kind of Grecian, with the nearby Alyrian sub-sector being similarly named after Illyria, which is very much in that same area. The Iolan Reaches hints at the Ionian Sea, and the ancient North African King Massinissa, the first king of Numidia, gave his name to the Massylean sub-sector.

Sticking with the classical theme, I had three very bright stars in the bottom left of Eridani, so the old crone/witch tropes pretty much demanded to be used. Again, I creatively switched a vowel, this time for the Graeae. Or rather, Maisey did, since at this point I was whining about naming stuff in the group WhatsApp chat.

System labels, or star icons?

I considered following the classic 40K map trope of having icons for each system that denoted its role (e.g. hive world, agri world, etc). However, since many systems have multiple worlds (and indeed multiple stars - this decision based on actual science) I decided against that, and stuck with icons that show the number and colour of the stars in each system. 

What's with the empty regions?

We deliberately wanted to have some areas be just broad brushstrokes, the idea being that the setting has the flexibility to have star systems added to it when we want something new to fight over and don't have it in the region already. That meant having some areas with established worlds, and some areas that emphasise the extent to which other people in our gaming group can contribute new locations and lore to the setting.

Refreshing the Wiki

As previous posts have attested, we use a wiki to track what happens in our corner of the 40K galaxy. This is all Tom's fault, since he's the Mechanicus cogitator masseuse; I just write and draw stuff. It was hitherto in standard Wikipedia display settings, which seemed a bit comedy given how hard we'd worked on the map, so we made more of an effort. Of course this also meant designing a new logo to fit the new look, but that was just a couple of hours of trial and error. Given that our biggest use of the wiki relates to our Inquisition roleplay, we decided to frame the logo as if you're browsing the archives of the Obelisk, our in-fiction Inquisition fortress in Cetus Major.

Click here to go to the wiki

Interactive map
Beyond working like any other wiki, the main thing to highlight on the practical level is the interactive map, which has now been updated. If you click on the map icon near the top right of any page covering a system or region, it links to a full screen map where all the words are hyperlinked, meaning you can load the map and then click on any word you see to be taken to the relevant wiki page. Once on that page, you just click the map/system icon at the top right to return to the map.

Of course, having a whole new sector to explore meant Tom had to go and add a whole raft of wiki pages to ensure there aren't any dead links. Some of those pages are, thus, wee baby stubs until we flesh those regions out. At the time of writing this, I've laid down basic lore for all the sub-sectors in Eridani, and of course everything in the more developed Achernar sector remains in place. I'll talk more about the lore we have got later in this article.

In case you're curious as to how Tom programmed the map, here's what he had to say on the subject:

Tom: My bit was easy; a little tedious to plot all the areas and link them up, but easy. Anyone with a little blessing of the Omnissiah can view the code to my page and see exactly how it was done. I used the HTML map tag for the main functionality and then found some javascript on Github to allow it to resize without breaking.

Welcome to the Achernar & Eridani Sectors

So here's the bit where we go into some of the actual lore. Obviously I'm not going to do so in much detail, since you can just browse the wiki, but it seems polite to provide a wee primer.

Click here for the interactive version

The Achernar Sector

This is our well-established area. It's right on the edge of the galaxy - indeed, its rimward edge is literally at the limit of the Astronomicon. This means bits of it have a frontier kind of feel; in border worlds like Erydimae, invoking Imperial authority is unlikely to hold much sway over the locals, for whom the Imperium is a distant abstraction, and the threats and business opportunities in the Halo Zone much more real.

That said, there are plenty of worlds in the region that are more classically Imperial, particularly sub-sector capitals like Cetus Major.

There are also regions like the Scyrian Expanse which haven't even been fully charted, and where most of the Imperial worlds are just newly-built outposts and mining operations. This is the area with the most known xenos activity, including SCY-039, a five-sun system utterly infested with greenskins, and SCY-028, or "N'Cea," a colony founded by a Tau fleet stranded on the wrong side of the galaxy following a malfunction with an experimental FTL device.

Click here for the interactive version

The Eridani Sector

This region is in many ways typical of the Imperium, in that of the hundreds of star systems in each sector, only a handful are under Imperial control. The Saedran and Massylean sub-sectors are relatively orderly places, with extensive trade running between the Imperial systems. Alyria, by contrast, is a collection of colonies who pay lip service to Imperial control and then spend much of their time in a state of conflict with each other trying to settle millennia-old grudges.

The Alyrian Sub-sector

The Iolan Reaches encompass possibly the most troublesome sub-sector. The few Imperial-held systems are spread thin, and surrounded by pirate wolf packs and xenos raiders. The region is a constant drain on Battlefleet Eridani's resources, but strategically cannot be abandoned as it connects the more prosperous Saedran and Massylean subs.

The sector's most notable stellar phenomenon is the Pheraean Rift, a dark region of space that occludes the light of the stars behind it, and seems to inhibit warp travel. As to whether this is a naturally occurring phenomenon or the work of xenos artifice is unknown, but the upshot is that anyone trying to cross the sector will need to follow the warp route through the heavily-defended Saedra system.

At a glance, the systems of the Graiae are perfectly normal Imperial colonies. The Ordo Hereticus, however, is very aware that the incidence of psykers in the colonies' populations is measurably higher than is normal. Whether this is due to some effect the Pheraean Rift has on the warp currents, or some other factor, is unknown.

There are other, more mysterious regions of Eridani. The lesser of these is the Targean Veil region, bordering on the equally unexplored Scyrian Expanse in the Achernar Sector. What alien threats may lurk in its many star systems remains unknown, and a superstitious Imperium stretched on all fronts finds itself disinclined to kick what may very well be a nest of bullet ants.

Finally, and most strangely, are the systems referred to as the Neophrae. Historical records indicate that there used to be trade with human settlements in this region, but that contact with those worlds was lost by the start of M36. A number of vessels that have since gone to explore the region have disappeared, or worse, found drifting in space, with no outer hull damage, a few signs of fighting in the corridors, and no bodies. Several eccentric figures in the techpriesthood suggest that if the Neophrae was home to a pre-Imperial human culture, there is a significant chance of finding archeotech, and possibly even STC data. As yet, though, they lack the influence needed to mount another expedition, given the apparent risks.

Thonis: a place for a space marine to call home

Of course one of the advantages of creating this initial draft of the Eridani Sector is that it's the home turf of my new marine army, and this in turn gave me a context in which to really develop their home system of Thonis. Clearly not satisfied with spending several weeks working obsessively in Photoshop, I made yet another map, this time of the four suns of Thonicia. I say 'map'... it's not to scale, so I guess it's more of a diagram. Once again, the map was the first thing I made; once I'd named and labelled the many planets in the system, I set about expanding their descriptions in the wiki.

This was also a chance to play with a very different visual style, although I did at least remain consistent with the font that was used in the main sector maps.

In closing...

With 40K's ninth edition almost upon us, and with it some solid tools for narrative gaming (thank you Crusade), I'm extremely stoked to start carving up the Eridani sector, not least of which because most of the group appear to be mustering Chaos armies. I'm starting to worry I'll be the lone defender of an awful fascist dystopia the mighty Imperium! Come at me, you heretical bastards.

Naturally the sector (and thus the wiki) will continue to develop over time. Leave a comment to let us know what you think so far, and if you've done something similar!


  1. That is just a fantastic resource! I wish I had some more time to work on a big campaign project like this; I have tried in the past. At the moment, though, I am incredibly time-poor teacher with two young children juggling at least 3 major tabletop gaming hobbies :-) Bravo!

    1. Uff, yeah, those are some epic time constraints. Hopefully you'll have more time when the kids are older and more independent :)

      Also thanks!

  2. I keep meaning to ask, any reason you changed the curvy warp routes into straight lines?

    1. Yes, the curvy lines method was quite finicky, and this method looks more like a map of a constellation. The alternative was to go super detailed and have them look super wiggly, but I figured it'd just look busy and take loads more effort for little reward.


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