Okay, let's go with that figure, 200 LY cubed. That would be 8 million cubic light years. If the stars in the Koronus expanse are spaced an average of 1 parsec apart, there would be 296,296 stars. That's give us our upper number. Assuming the stars are more distantly spaced as the galaxy approaches the Halo (they seem to be, but there's some brown dwarf arguments stuck in there), what then is the average parsec in the Koronus Expanse? I went with 4 LY, which gives us 125k stars, and I rounded down to the nearest big "0." Both these numbers are within the margin of error, but so is 30k, or even 10k, or 2 million. Probably our biggest assumption here is that the Koronus Expanse is indeed an "average sector."

And btw, in the first two campaigns I ran, I went with a parsec being 10 LY, resulting in only 8,000 stars in the Expanse, which also worked pretty well. In this last campaign I've run, though, I wanted more and larger Rogue Trader fleets out there. While my star density figures are based on some pretty sketchy Terra circa-21st century science, my merchant and warship figures are based on real world numbers and tonnage. Heh. Those are also pretty questionable when comes to applying them to the vastness of the galaxy, but I made do with what I had available.

Okay, let's go with that figure, 200 LY cubed. That would be 8 million cubic light years. If the stars in the Koronus expanse are spaced an average of 1 parsec apart, there would be 296, 296 stars. That's give us our upper number. Assuming the stars are more distantly spaced as the galaxy approaches the Halo (they seem to be, but there's some brown dwarf arguments stuck in there), what then is the average parsec in the Koronus Expanse? I went with 4 LY, which gives us 125k stars, and I rounded down to the nearest big "0." Both these numbers are within the margin of error, but so is 30k, or even 10k, or 2 million.

Stellar density near Sol is estimated as 0.004 stars per cubic light year .

8 million cubic light years * 0.004 = 32 000 stars.

Also, from the Core Rulebook (page 315): "Each Segmentum is divided into sectors varying in size according to local demands and stellar density. A typical sector might encompass seven million cubic light years, equivalent to a cube with sides almost 200 light-years long."

(7 million cubic light years * 0.004 = 28 000 stars, and a 191 LY cube.)

Sector sizes vary depending on "local demands and stellar density ", so sectors closer to the rim will probably be a bit bigger on average, while having the same approximate number of stars.

I figure most of those star systems are worthless and/or effectively inaccessible by warp travel.

Oh! Countered with Wikipedia! Check and Ma....oh wait a minute!

"In the solar neighborhood, the stellar density is about one star per cubic parsec (one parsec is 3.26 light-years). At the Galactic core, around 100 parsecs from the Galactic center, the stellar density has risen to 100 per cubic parsec, crowded together because of gravity."

http://abyss.uoregon.edu/~js/ast122/lectures/lec26.html

And seriously, if you want to get into the science of it, try this out for some light reading...

http://www.astro.washington.edu/users/ivezic/Publications/tomographyI.pdf

That will give you commonly accepted numbers of near-space. Or if you're into the whole dark matter thingie, try this...

http://www.astro.caltech.edu/~george/ay20/Ay20-Lec16x.pdf

And if you want to know how this compares to other galaxies (it's hard to measure our own galaxy...the whole forest through trees thing) try this...

https://www.physics.rutgers.edu/~gawiser/689/lindner_dickinsonetal04.pdf

My favorite part of this last one is near the end of the presentation..."Possible solution:

And let's not forget...

"A typical mass density for a globular cluster is 70 M _Sun pc ³ , which is 500 times the mass density near the Sun."

http://en.wikipedia.org/wiki/Stellar_density

Off-hand, I can think of 2 globular clusters alluded to in the Koronus Expanse. Of course, this measures mass densities of suns, not number of suns. A single B-IIa can account for a lot of suns!

Look, I think all we really want are some numbers that work within our conceptual framework of ship numbers. We all want to know the scale of fleets, or that's what I thought the discussion was. That number will be necessitated by the mass and volume of goods flowing from operational starports and landing sites. How many ships does it take to move this stuff without the warehouses piling up?

I think I gave some very reasonable and workable numbers. I also gave some margins of error that I've worked with in the past. Whether you go with the 8k or 300k figure, or 32k if that's your Gospel sticking point, just take the number of ships I reckoned with and divide your holy gospel by those numbers.

Or don't. Make your own universe! I always chuckle when the fanboys start quoting facts and figures derived from sources that more than likely majored in creative writing. Not that I have a problem with that sort of degree, it's just not a good source to quote figures from. There are notable exceptions, of course. David Brin comes to mind.

Poul Anderson taught me Tau and it's ramifications- and I'm not talking about the blueberries.

The great thing about the numbers you came up with, Errant Knight, is that they seem to be scalable. If you want to use a smaller number of stars for your sector, reduce the number of ships proportionally, no? Simple.

Absolutely. Erathia wants big fleets, so to keep it believable, use a larger number of stars. Iku Rex wants a smaller number of stars. Fine, also, just keep in mind that this entails smaller fleets. There are other factors that could increase the density of a merchant marine, but that's something people should at least consider as they create their campaign worlds. Okay, the average person out there doesn't always consider such things, but we should play to the best in our world, not the average.

"In the solar neighborhood, the stellar density is about one star per cubic parsec (one parsec is 3.26 light-years). [...]"

http://abyss.uoregon.edu/~js/ast122/lectures/lec26.html

Yeah, I'm pretty confident that's BS. One star per cubic parsec means we should find around 500 stars within 5 parsecs of the Sun. Do we? Nope. Maybe 60. (Depending on how you define "star".) There may well be more of course, but 450 more seems excessive.

My guess is your guy forgot a "0." . Make it 0.1 stars per cubic parsec and you're probably not far off.

As for the 0.004 per cubic LY estimate, it is not some random number made up by a Wikipedia-editor.

Here's one source :

In the vicinity of the Sun , stellar density

can be determined from the various

surveys of nearby stars and from estimates

of their completeness. For example,

Wilhelm Gliese’s catalog of nearby stars, a

commonly used resource, contains 1,049

stars in a volume within a radius of 65 lightyears.

This is a density of about 0.001 stars

per cubic light-year. However, even this

catalog is incomplete, and its incompleteness

is probably attributable to the fact

that it is difficult to detect the faintest stars

and faint companions, especially extremely

faint stars such as brown dwarfs.

In short, the true density of stars in

the solar neighbourhood is difficult to

establish. The value most commonly

quoted is 0.003 stars per cubic light-year,

a value obtained by integrating the van

Rhijn luminosity function with a cutoff

taken M = 14.3. This is, however, distinctly

smaller than the true density as calculated

for the most complete sampling

volume discussed above and is therefore

an underestimate. Gliese has estimated

that when incompleteness of the catalogs

is taken into account, the true stellar density

is on the order of 0.004 stars per cubic

light-year, which includes the probable

number of unseen companions of multiple

systems.

-- from "The Milky Way and Beyond", page 35. Published in 2010 by Britannica Educational Publishing.

So, 0.004 is actually the high estimate.

And seriously, if you want to get into the science of it, try this out for some light reading...

Posting random pdfs you found with Google isn't going to convince me that you have some special insight. If any of those links contain relevant information, by all means, refer me to to the important bit.

Off-hand, I can think of 2 globular clusters alluded to in the Koronus Expanse.

Off-hand, that sounds very unlikely, both with regards to the fluff and to the real world science.

Look, I think all we really want are some numbers that work within our conceptual framework of ship numbers. We all want to know the scale of fleets, or that's what I thought the discussion was. That number will be necessitated by the mass and volume of goods flowing from operational starports and landing sites. How many ships does it take to move this stuff without the warehouses piling up?

I think I gave some very reasonable and workable numbers.

I don't think you did. It's hard to offer more specific criticism, since you gave no in-depth justification for most of your numbers.

Not that I care much. It makes more sense to start by guesstimating the number of ships and/or inhabited worlds based on the fluff . Then you go from there. If the fluff suggests that there are, say, a few hundred systems in the Expanse populuated by humans, any line of reasoning that concludes that there are 10 000 is flawed.

Whether you go with the 8k or 300k figure, or 32k if that's your Gospel sticking point, just take the number of ships I reckoned with and divide your holy gospel by those numbers.

I'm not sure how you got from "more like 30 000 from what I could find" and calculations of 28 000 and 32 000, to "holy gospel"... You're the one getting exited because I pointed out one problem (out of several) with your "reasonable numbers".

I can't respond much to this. From what I can see, your intuition trumps the bazillions of hours of observations made by astronomers with considerable education and access to this world's best telescopes. Maybe they misplaced a decimal point? That's your reaction? Really? Ok, live in that world. Lots of people watch Fox "News."

You throw out a Wiki stub as your source. You pooh-poohed Wash U, Oregon U, Cal Tech, and Rutgers' astronomy departments, and let's be honest, you didn't bother to read them or you wouldn't have responded the way you did. And, to follow up, you whip out the Encyclopedia Britannica. Nature magazine found Wikipedia, sans typos, to be more accurate than Britannica. Your own source mentions three distinct "commonly accepted" calcuations. That's a walking talking oxymoron.

If you want to create your game world by basing your numbers on the "fluff," whatever that is, knock yourself out. Seriously. Have fun. I'd get laughed at, but maybe my audience is tougher than yours. Not that I'm asking for an easier audience. I'll build my game worlds based on the universe I live in, which changes every decade, btw, as we learn more about it.

If you want to take a poke at any of my other numbers, feel free. I'll be happy to quote numbers from books or websites you're likely to never read. Expect some mistakes, though, because I'll be quoting from memory. You've already made it clear that reaching behind me to look up exact figures is a waste of time.

More to the point, it's only tangentially related to the topic.

I can't respond much to this. From what I can see, your intuition trumps the bazillions of hours of observations made by astronomers with considerable education and access to this world's best telescopes. Maybe they misplaced a decimal point? That's your reaction? Really? Ok, live in that world. Lots of people watch Fox "News."

Your indisputable source is a single sentence one guy wrote on his webpage.

Then you added some random pdfs you found with Google. But you are incapable of explaining why they are relevant, or of quoting the relevant part. How very odd.

You also seem to have overlooked my little experiment above. Let's try again, with more detail.

A sphere with a 5 parsec radius around the Sun has a volume of around 524 cubic parsecs. Thus, your prediction is that we'll find around 500 stars in this volume of space. My number suggests around 70.

If only there was some way to test these predictions!

But wait, there is. After all, we have "bazillions of hours of observations made by astronomers with considerable education and access to this world's best telescopes", as you put it above.

I wonder what they've found...

Oh, right. Around 60 stars. http://en.wikipedia.org/wiki/List_of_nearest_stars_and_brown_dwarfs

(I know, I know - you'll probably be along shortly to explain how anything written on Wikipedia is automatically wrong, with no need to offer any evidence.)

... "fluff," whatever that is, ...

For future reference, "fluff" is the story elements of the game – characters, setting, plot, flavor, etc.

I'd get laughed at, but maybe my audience is tougher than yours. Not that I'm asking for an easier audience. I'll build my game worlds based on the universe I live in, which changes every decade, btw, as we learn more about it.

I would however love to see your "real world" numbers for human settlement patters and safe warp routes between stars in the Koronus Expanse, or trade figures and freighter cargo capacity.

I didn't even know scientists had cracked the secret of warp travel in the "real world ". This is very exiting! And scary. Are they taking the necessary precautions to protect against demonic incursions?! Is this information perhaps also hidden somewhere in the paper you posted earlier?

I pointed out earlier that my numbers for merchant ships per capita, the density of ports-of-call, etc. were based off real world examples of the15th-19th centuries, and were sketchy to apply to interstellar commerce, but that's all I really had to go with. The numbers work for me, though. If you want to quote me out of context to cover your tracks, feel free. I'll still sleep well tonight.

What I find exciting from an RPG standpoint is the number of stellar remnants, brown dwarfs, and other objects with little or no luminosity that might contain planets rich in minerals. There is a lot of unaccounted for energy/matter in the universe and scientists are beginning to account for some of it. This gives me, as GM, a huge number of new environments I can populate my map with for my players, and an even greater number of new and original endeavors for them.

So thank you Iku Rex. Without you I would not have looked up some of this stuff and furthered my knowledge of the stars. I've already begun to draw up an endeavor based around a stellar remnant I'll merge with a randomly-generated system from Stars in Inequity. It's very promising.

Expanding this a bit further, should there be a Winterscale-Chorda War, which side would other named dynasties support?

Saul would likely remain neutral.

Armengarde would likely work for both sides, running smuggling operations. But there's a rivalry there with House Saul that could become a second, smaller war within the larger one.

I think that would be ultimately up to the GM where each of the other named RTs land. I imagine most would play both sides against each other or only sign on for short contracts or over particular locations.

The only clear RT I'd put in Winterscale's camp is Sarvus Trask. Otherwise, just take a list of all the RTs and flip a coin. I imagine most might take the opportunity to raid both sides. Why not get richer and more powerful at the expense of two of the largest dynasties? Though once the dust settles you have to hope that the victor is too exhausted to hunt you down.

Oh I will say that Wrath Umboldt would stay out of the fighting. On account that he sits on Port Wander and hands out advise and probably has a giant tip jar. His advise would probably to not get involved.

I don't think the Saul/Armengarde rivalry would got hot or get sucked into a bigger Winterscale/Chorda fight. The Winterscale/Chorda conflict would likely be centered around Lucien's Breath and radiate out from there. Saul's rivalry with Armengarde is over shipping and their rivalry actually helps them in the long run. It forces Saul to come up with new ways to tighten down on smuggling while Armengarde has to come up with ways around that. A shooting war with them would be bad for business. At least that is my take on their relationship from their blurbs. Though if they did get into a fight my money would be on Saul. His PF is stated at 93 to Armengarde's 50. Saul has the coin to hire all the guns he needs. (EotA 108, 111)

I laughed so hard at the brief flamewars that took place here that I have to bring this back to life.

It's all a matter of perspective. When you look into the sky, what do you see?

A region of space where FTL-drive is nearly impossible might be too full of gas clouds, stars spaced closely together, intersecting gravity wells, and other phenomena that tend to destroy starships that attempt FTL-travel. One person might call it Globular Cluster X-427. Another person might call it the Screaming Vortex. One person might want to explain why a thing becomes impossible. Another person might simply write it off as Warp magic and leave well enough alone. Quite frankly, the end result is the same.

To the OP, which of the two does my party support? It would likely be Chorda by default, considering Caligos Winterscale isn't on good terms with the party's House. That, and the whole bit where he cut off my character's arm in an honour duel, stabbed him through the heart with his own sword, and then proceeded to cut off both his hands and throw them into a bag...all because my character killed a distant cousin of his in a prior duel gone wrong.

My character is still alive (that's what fate points are for, thank goodness the doc had a stasis unit of some kind hidden in the body bag so he could be revived later), and now one of the other players (a Rogue Trader) who wasn't even involved with the duel wants to bring Winterscale down in every way possible.

We'll see how that goes though

To the OP, which of the two does my party support? It would likely be Chorda by default, considering Caligos Winterscale isn't on good terms with the party's House. That, and the whole bit where he cut off my character's arm in an honour duel, stabbed him through the heart with his own sword, and then proceeded to cut off both his hands and throw them into a bag...all because my character killed a distant cousin of his in a prior duel gone wrong.

My character is still alive (that's what fate points are for, thank goodness the doc had a stasis unit of some kind hidden in the body bag so he could be revived later), and now one of the other players (a Rogue Trader) who wasn't even involved with the duel wants to bring Winterscale down in every way possible.

We'll see how that goes though

My Calligos Winterscale also likes to cut off the arms of people who challenge him to duels. Or disrespect him. Did he cut off your character's arm and then pointedly cut the hand off as well? Did he give the rest of the arm back as change?

To the OP, which of the two does my party support? It would likely be Chorda by default, considering Caligos Winterscale isn't on good terms with the party's House. That, and the whole bit where he cut off my character's arm in an honour duel, stabbed him through the heart with his own sword, and then proceeded to cut off both his hands and throw them into a bag...all because my character killed a distant cousin of his in a prior duel gone wrong.

My character is still alive (that's what fate points are for, thank goodness the doc had a stasis unit of some kind hidden in the body bag so he could be revived later), and now one of the other players (a Rogue Trader) who wasn't even involved with the duel wants to bring Winterscale down in every way possible.

We'll see how that goes though

My Calligos Winterscale also likes to cut off the arms of people who challenge him to duels. Or disrespect him. Did he cut off your character's arm and then pointedly cut the hand off as well? Did he give the rest of the arm back as change?

Yeah, my character got to keep the arm, all Winterscale wanted was the hands of the man who "murdered" his third cousin (the only one he happened to like, as it was). This was fortunate, because my character has (hidden) sub-dermal armour implants, meaning if he'd lost his arm, he'd have to get new ones there. Considering they were non-standard, it would have been awhile.

As far as the game goes, the universe believes him dead, because it probably isn't a good idea to make mention of the fact you're still alive when you died at the hands of the most powerful man in the expanse after he challenged you to a duel to the death. Duel to the death is supposed to mean what is dead stays dead, at least one would assume.

His time will come though, our Rogue Trader is plotting his demise, though it could just mean everyone gets blown up by the Emperor's Vow in the end too

Cool update, it seems my group ( I play the Void-master of the group) has managed to find one of Chorda's legitimate sisters for our as yet unknown party....... though we have learned that our mystery boss has some friends in very high places.... in this case the Tricorn Palace. While our small scale piracy of Winterscale has netted us a little extra PF, we are finding a lot more guns aimed at us than I am comfortable with being aimed at my pride and joy (I don't care what the RT says the ship is MINE!). So we have taken a small detour to a little uninhabited system with a couple nice planets to restock essentials, do some repairs, and let the heat fade a little bit before we poke our noses out again.

I don't know about the rest of you but being woken up from stasis aboard an unknown ship and then being essentially carried into a sparse room with stormtroopers and an Inquisitor and being told and I quote "I am here to test you for taint and heresy, if you survive you will once again be able to hold your head high as an Imperial citizen". We left with the cliffhanger of being led from the room with only the astropath being allowed to stay (we figured so the findings could be sent instantly) and being told that as the door closed behind us we hear a scream like someone's soul is getting pulled out of them then being sent through a blender. So hopefully next session we get some answers and maybe the astropath gets to roll for insanity from what she see's.

Winterscale. He was more of a friendly chap to my players so they just backed him.