I read a few things about warp travel in 40k and it got me thinking. Why does imperium send soldiers from Tallarn for example into segmentum obscurus or far reaches of ultima? Since journey from terra to calixis take 4 years in real time according to fluff why would they send soldiers from so far away? Or how did they muster so many forces for third war of Armageddon or 13th black crusade since at least half of these regiment would need years to travel to said places. Not to mention that sometimes one regiment or space marine chapter is in ultima segmentum in 998M41 only to show up on Cadia year later when such jurney would take few years of real time. Are GW writers just lazy or maybe GW has some new fluff that i am not aware of regarding warp travel times?

I was thinking about throwing my players into region which would be attacked by hive fleet leviathan but then i realized it would not make sense to move soldiers from calixis to ultima/tempestus since it would take years before they arrive and tyranid threat will be long gone (one way or the other)

Because 40k as a franchise does not have a uniform canon. Warp travel times differ depending on the source you're looking at, so FFG may have simply made up other standards for it, just like their starships are bigger and with way more crew than the numbers Andy Chambers wrote up for Battlefleet Gothic.

Thanks for clarification Lynata. So we can assume that some ships can travel faster so it won't take few years to move troops across segmentum. It's kinda sad they don't include fluff like this in only war books (or any w40k line books) and we players have to look for info (which is kinda vital info for me at least ) in over decade old codices

I also noticed that most of the maps are not reliable source of imformation. For example Tesla prime, Jorn V and Rigant on one map are in segmentum tempestus on the other in segmentum ultima and on tyranid map they are in veiled region. Any idea which w40k galaxy map is most accurate to the fluff? Preferably a map which is more detailed than 7th rulebook map which only show a few planets.

Travel times depending on the ship is mentioned in the Rogue Trader RPG as well - plus there is always the possibility of a ship being thrown off-course, which by nature of the Warp can significantly alter its timetable and make it arrive several years late, or perhaps even sooner than it actually departed.

Still, I bet most discrepancies are simply a result of many if not most writers pursuing their own vision of the 41st millennium (see some quotes on the topic of "canon" I gathered here ). Sometimes it is just easier to accept this and disregard contradictory fluff - although other times I actually find it fun to come up with potential explanations how two seemingly contradictory sources can still fit together. It all depends on just how feasible it is, so personally I decide it on a case-by-case basis.

Any idea which w40k galaxy map is most accurate to the fluff?

Given that "the fluff" is just a collection of contradictory opinions, I'd say this depends entirely on how you weigh the various sources, so that is a rather personal issue. Myself, I'm prioritising GW studio stuff such as codices or White Dwarf or Citadel Journal (and I've even started to develop a "micro-preference" for earlier editions over what they are printing now), simply because that is how I got to know the setting - but others stick more to specific Black Library novel series, and yet others are looking at FFG's RPG books first.

Each of these approaches is equally "right". The only thing that matters is that all players in your group share a common ground when it comes to expectations from the game world, so perhaps you can get some input from your party on this subject, too.

Yeah, lots of things can alter a trip through the Warp, from little things like how well the Navigator peered into the Warp this time, to what sort of ship you are flying, and what strange, arcane devices it might have. In Rogue Trader, you might have a ship with a Background that can shorten warp trips, for whatever reason, or a device that is later installed, and does the same. Your Navigators, and no one else's, might have access to ancient (or just recently made by them) star/warp maps, which show "safe passages" through the Warp, allowing your ship to make it through faster, and/or, much more importantly to the plodding Imperium, more safely. If a warp storm springs up, and pear-shapes your trip, you might have problems, or if you accidentally drift into a warp calm, you might be stuck, where otherwise your journey was set to be short. The Immaterium can also have its own hand in things as, like Lynata said above, there are scenarios where you might arrive at your destination before you actually left your starting point. As with so many things, who you are, who you know, and what you have can make all the difference between a safe, quiet trip, Gilligan's Island in Sphess, or nightmares to make the end of Event Horizon seem tame, by comparison, from which there will also be no escape.

Some folks might also quietly argue, and you can take this however you might feel on the issue, that the faith of the crew will effect things. While Humans are no gestalt psychic cheese, able to fly through space in junk that shouldn't work, and scaring away daemons who themselves induce fear, and probably serve Khorne, and the God-Emperor can't possibly protect every vessel of the Imperium that plods the space ways, their faith in their Emperor can have miraculous benefits, from time to time, and a ship strong in that faith might get a quiet voyage, at least comparably, where a less pious crew might be left to fend for themselves. Also, much like airplanes today, we only really think of the few that crash when, comparatively, many more fly with no hiccups. While the travel mode in the Imperium is, in grimdark fashion, much less safe, if it didn't still frequently, even usually work, the idea of the Imperium being a galaxy-spanning Human empire would have fallen away. It's just that those few that do go poof are considerably terrible losses, and the percentages aren't as good.

Is there any sort of reckoning of distance between the worlds of the Spinward Front? I imagine it could take weeks or months, but I don't want it to be unrealistically short or long (besides the awkward times when the Warp makes it so) and I am struggling to come up with distances. Short of trying to plot it with RT mechanics, is there anything official?

It is official table at least i think so, not sure where i got this. But these travel times are unrealistic since minimum travel time from calixis to terra would be something like few months and 4-5 years would pass in real space. For example trip from Vibrius to Kalf or Kalf from Kulth would take few hours for ship crew and a week time of real space so it's ok but the longer the distance the more unreasonable travel times are. And that was the point i made this topic since i don't belevie that so many regiments are send to another segmentum (like catachan to outer reaches of ultima segmentum) using this travel times since it would take years for them to reach destination.

Some folks might also quietly argue, and you can take this however you might feel on the issue, that the faith of the crew will effect things. While Humans are no gestalt psychic cheese, able to fly through space in junk that shouldn't work, and scaring away daemons who themselves induce fear, and probably serve Khorne, and the God-Emperor can't possibly protect every vessel of the Imperium that plods the space ways, their faith in their Emperor can have miraculous benefits, from time to time, and a ship strong in that faith might get a quiet voyage, at least comparably, where a less pious crew might be left to fend for themselves.

That reminds me of how it's been said that Saint Sebastian in M37, and Saint Joachim in M41, were both able to "calm the Warp" in order to arrange safe passage for their fleets. Of course, with 40k, this could also just be coincidence, or a lie, or even the workings of other beings dwelling in the Warp.

"Junk that shouldn't work", though? That sounds a bit too orky imho -- they still have stuff like Geller fields etc!

It is official table at least i think so, not sure where i got this.

How can you be so sure, then?

But yeah ... perhaps I wouldn't say "unrealistic", it just doesn't add up with what has been written elsewhere, especially in the bigger picture (various armies showing up across space in a relatively short timeframe, as you mentioned).

The simple answer is ther is no answer. Alot of 40k authors say there is no official cannon. It's just what they make It to be. Warp travel time is a fickle thing at best of times. It can take weeks or months to a simple jump in the same sector maybe or a few days to travel to another sector it all depends on the story you want to tell. In rouge trader you have to tell them how much time passes.that means you can be a **** and say it took over a millennia if you really want. So just make It up.

Some folks might also quietly argue, and you can take this however you might feel on the issue, that the faith of the crew will effect things. While Humans are no gestalt psychic cheese, able to fly through space in junk that shouldn't work, and scaring away daemons who themselves induce fear, and probably serve Khorne, and the God-Emperor can't possibly protect every vessel of the Imperium that plods the space ways, their faith in their Emperor can have miraculous benefits, from time to time, and a ship strong in that faith might get a quiet voyage, at least comparably, where a less pious crew might be left to fend for themselves.

That reminds me of how it's been said that Saint Sebastian in M37, and Saint Joachim in M41, were both able to "calm the Warp" in order to arrange safe passage for their fleets. Of course, with 40k, this could also just be coincidence, or a lie, or even the workings of other beings dwelling in the Warp.

"Junk that shouldn't work", though? That sounds a bit too orky imho -- they still have stuff like Geller fields etc!

I was referencing Orks, so I HOPE it sounded Orky I suppose Greenskins might have something like Gellar fields, though I have no idea how. I'd say there's no way they could build that, and someone will remind me that some Orks simply have"certain knowledges" inbred into them, on a genetic level. Mekboys don't know how they build some of their crap, any more than Marvel Comic's Forge does; his mutant power is that he can invent stuff. (In truth, it is something like "on a subconscious level, he can attempt something numerous different ways, simultaneously, and glimpse the future to see what results are favorable. Then he "picks" the one that works, and that's what he does. It's also why he hates his power; there is no likelihood of failure, nor any epiphanies or inspirations, as a result. It just works, and is kind of boring, which, for an inventor, can suck.) Still, I was more under the impression that Orks' gestalt psychic mcguffin imposes their own theme on the warp, in their traveling vicinity, thus making most daemons not want to bother them. Daemons also get little out of it, as Orks are often written as immune to Chaos, beyond being frequently duped into being a weapon.

I was referencing Orks, so I HOPE it sounded Orky

Ohh, okay - misunderstanding then! I had thought that would still refer to humans as it sounded like a list rather than comparison.

And yeah, I recall reading that Orks travel through the Warp unprotected, but given how the setting works I also wouldn't be surprised if there was a novel that said otherwise.

It's Orky, but I don't even entirely know how they travel through the Warp. If there wasn't that little bit in Frozen Reaches where one exits the warp, and immediately goes BOOM!, I wouldn't be sure they do in the typical way. I have no idea what resides within the warp drives "fuel casket", other than Faith & Coin says it can REALLY screw you over, but I'm not sure the Tech-Priests REALLY know, either, and while it could be programmed into their genetics, so their Mekboyz just know, I don't think the warp was quite like it is when the Old Ones wrote that code (one less Chaos God, a lot less mess in there), so I'm surprised they can still do it so easily, with such small risk.