I've been reading the Rogue Trader rulebook and been pondering:

As I understand it: The Astronomican is the psychic beacon that allows navigators to travel vast distances in the warp without getting lost or swept off course. Ships without a navigator are limited to jumps or around 4 light-years.

Question: How do other races travel the warp? Do they also latch onto the Astronomican or do they have different ways of moving large distances?

Eldar travel through the Webway gates.

Tyranids use the will of the Hive Mind to travel through the Warp unimpeded.

Necrons have highly advanced inertialess engines that allow them to go crazy fast.

The Tau bounce their ships off the veil between the Warp and realspace. It's safe, but doesn't let them travel very far.

Orks get around in one of two ways; they either just infest a space hulk and wait around until it arrives in a system, or bolt a few Warp-capable craft onto one of their Roks and 'apparently' Wierdboyz function as Navigators.

Kroot appear to have developed their own method of Warp travel based on Ork technology.

Errant said:

Note that the Necron drives are real-space drives and they never touch the warp, don't accidentally have a necron ship in the warp on purpose.

Mmmm... And this bring up the question, how in the hell can a navigator navigate with just a single point of reference? It's called Triangulation for a reason, after all xD (and space is tridimensional, too...). Not to mention, you can time travel while crossing the Warp...

Is it actually stated anywhere that Astropaths use the Astronomicon to triangulate their position? If it does, well, I got nothing

Otherwise:

I would suggest that they don't actually triangulate, or even use it for navigation in any literal sense. In fact, I would be surprised if any of the laws that governed terrestrial or stellar navigation applied in any appreciable way in the warp. Rather, I would say, they use it in some way as an anchor to ground their will against the tides of the warp...

or something like that, anyhow.

Argus Van Het said:

Easy. The Warp isn't a three-dimensional space. At times, it may not even have one dimension. At others, it may have several billion distinct dimensions, some of which are inherently contradictory.

The Warp doesn't obey the natural laws of the universe. This doesn't just include things like gravity or time, but space as well. It is a place where up is left, down is tuesday and logic is behind the bike sheds having a smoke rather than paying attention. Consequently, things work there that shouldn't in realspace, and things that might work in realspace won't necessarily work in the Warp.

It is, amongst other reasons, why Navigators exist - because they're trained and genetically predisposed towards being able to guide a ship through the Warp, no matter how impossible it might seem.

I see some possibilities, but I basically agree with N0-1_H3r3 and Crow

1. There might be enough other points of reference to see, such as local warp storms etc. They are just not as stable as the Astronomican, which can thus mislead even Navigators.

2. Maybe the Astronomican consists of multiple beacons.

3. It's the warp! If you want to understand it, switching of logic and all sane parts of your brain is the very least you are expected to do.

The story Lacrymata in the book Deathwing published about 1990 has some interesting perspectives of a navigator doing its job.

And there are no points of reference in the warp save His celestial beacon, none that you should bother to trust anyway.

I'll quickly note that that astropaths don't triangulate or otherwise orient themselves according to the Astronomican (or if they do, do so for reasons other than navigation). Navigators (i.e. functioning members of the Navis Nobilite) do so. It seems tobe a common misunderstanding, and it is somewhat understandable, given the similarities of the names. Just remember, astropath is short for "astral telepath", or more commonly "astrotelepath": a telepath strong and disciplined enough to send a message over interstelar distances. The Astronomican is a psychic beacon formed by hundreds of telepaths even stronger than that, all screaming/chanting at the top of their brains and focused by the Big =][= on his Throne (which explains the unusual beam shape of the beacon, and the fact that it is visible from so far away).

There are a number of other, smaller psychic beacons scattered around the Imperium, but their signals lack both the shape, strength and definition of the Astronomican. The most famous of these (from our meta point of view, anyway) was guarded by a Commandery of Battle Sisters: Sanctuary 101.

I'll also note that my understanding of navigation in the Empyrean is that it is closer to very early sailing, before the development of a sextant and a sufficiently accurate clock. You take your starting position (triangulated, in this case, from star fixes in real space), and orient on certain fixed directional indicators (such as the Astronomican, or a smaller, local psychic beacon), just as a mariner would a compass, or the Pole Star, and make an estimate of your movement based on intentional navigation and leeward drift (in this case, the currents of the warp), and when you think you're approaching your destination (or starting to get lost), you make landfall (planetfall? starfall? translate back into real space, in any case) to re-determine your position, then repeat as necessary.

A Navigator, especially when equipped with a good Navis Prima (think of them as a cross between the Sailing Directions and a ship's ruter), allows a ship to better estimate their progress, and the amount of drifting to leeward that has occurred, thanks to their ability to see warp currents, meaning that the amount of time (and distance) that a ship can travel before it must re-establish its' position is far greater. Travel without a Navigator is limited to roughly a parsec at a time because any further is increasingly inaccurate. It'd be like trying to sail from one port to another by dead reckoning alone. In a fog. Dover to Calais might be alright, but Portsmouth to Boston MA would be doomed to get very lost indeed.

Oh, and No-1, I like that description of the warp; I might well appropriate that.

The Astronomicon, it's a beacon made of thousands of psykers and focussed by the Emperor. It casts it's light across a roughly spherical area in the warp.

Canonically Navigators use the fixed point of Terra (insofar as any planet is fixed) and their realtive position to it and calculate in a highly conditioned mental framework the thousands of calulations required to make the best course to their destinaion, then when within the warp having worked out how the astronomican should appear to be throught their journey they use it as a reference point to check their progress through the boiling madness of the immaterium.

In my own opinion it also allows Navigators to "see" the currents of the Warp more clearly too by creating psychic "ambient light" in the warp.

Hell, it was a rethorical question, but the answers are quite good ^^. If minor version of the Astronomican are scattered in the galaxy, well, I can see the possibilities for some interesting adventures for Dark Heresy...

And of course the "triangulation" word I used was just some sort of analogy: since time travel is possible in the warp, you would need a signal able to make predictible changes as time goes on (or be able to notice the subtle variations in position three beacons would make... good luck with that XD).

No to multiple beacons, they'd just be confusing. Imagine a black moonless night full of roilng smoke in a black volcanic desert with hundreds of signal fires in it.

A navigator could mistake one signal for another and lose his way/forget which one to steer by/get everyone killed by coming out of the warp somewhere uttlerly unsurvivable based on a flawed decision.

Plus who the hell would want the thousands of psykers that it would require on their planet without the defences of Terra? Sounds like an invitation for the evils in the void to come and feast on tasty psykers to me.

Well, that's pretty much what happened at Sanctuary 101- the necrons arrived, slaughtered the Sororitas commandery (or it may have been a preceptory; I'm not sure the Sisters' fluff had been developed enough to differentiate when they wrote the Massacre at Sanctuary 101 battle report) guarding it, and disappeared along with every psyker in the place.

I should also note that the Astronomican on Terra does not project a spherical signal- it must be something of an ovoid shape, with Terra far closer to the limits of the signal at the "fat" end, rather than at the barycentre, as Ultima Macharia (the final world Macharius conquered before he was forced to turn back or be lost beyond the light of the Astronomican), is in the galactic west (maybe 1/8-1/5 of the way round spinward from Terra, and far to rimward), while there are worlds on the Eastern Fringes, 2 or 3 times as far away which apparently have no problem seeing its light (Calth, for example, or Kar Duniash).

Given that, and given that smaller depots would obviously not have Him to amplify and focus it, their signals are going to be weaker, local beacons, probably mostly spheroid, and the fact that we know a psychic choir can sing information with their brains, I think there is not much chance in a Navigator accidentally locking on to the wrong beacon.

Alasseo said:

A psychic choir, broadcasting into the mind of a navigator or psyker while in the warp... seriously?

Are you insane?

Why on earth do you think that vital members of crew should be open to psychic intrusions in the most dangerous psychic environment imaginable? that's just begging for hideous problems with the boiling deamonic insanity outside.

Quite simply, I'm not. I'm suggesting that since we know that a 'pathic choir can transmit information, they use that capability to alter the way their beacon "looks" to Navigators and others viewing it from the Warp, so that it can be distinguished from other such beacons.

That said, there have been a number of occasions in the novels where a ship's astropath receives a message while in the warp, although those were all back in the day before Black Library was split off from GW. True, they have since been reprinted, but it's still an older conception of 40k fluff.

As mentioned above, the story Lacrymata gives some nice insights into how a Navigator may view the Warp.

In this story the Navigator uses a Warp Helm, which I assume gives him some form of electronic readout, displaying Warp disturbances that have been detected by the ship's sensors.

The Navigator, enclosed in his observation dome and making reference to his Warpscreen, looks out into the Warp and his third eye overlays his normal sight with visions and symbols that allow him to interpret the chaotic swirl assaulting his senses, and steer the vessel accordingly. It is my understanding that how a Navigator views or interprets the Warp is unique to the individual - some viewing it in two dimensions, some in three, and so on.

The Astronomican, rather than giving a physical point of reference in a realm that doesn't really possess them, provides more of an emotional and spiritual support to the Navigator, lending clarity and strength in an otherwise overwhelming realm of pure and turbulent emotion.

The psychic scream of this beacon in effect drowns out, or at least diminishes the emotional/psychic assault which threatens to mislead or distract the Navigator; providing a calming influence which allows him to ignore the many distractions of the Warp. The light of this beacon illuminates the path ahead and grants the Navigator the conviction to make the necessary steering decisions.

The Navigator's faith in the Emperor therefore plays a large part in determining the strength of support provided by the Astronomican, the clarity with which it is perceived, and the degree to which the Navigator can clearly interpret the path before him.

The significant role faith plays in the perception and function of the Astronomican explains why other races are unable to gain the benefits of this beacon, or to use it effectively for their own Warp navigation.

Lacrymata also talks of the mental residue left in the Warp by the minds of other Navigators who frequent the trade routes near Holy Terra. This residue may itself function as a minor navigation point, in the form of gigantic gates or yawning fanged maws in the most frequently used Warp entry/exit points. My guess is that these "landmarks" could only be relied upon in the most stable of Warp lanes...

Theboyidiot is no idiot. I'd say that post is exactly on the money!

N0-1_H3r3 said:

I really just wanted to jump in to say that this is one of the more amusing yet completely reasonable explanations of how navigation works in the warp. Additionally, the light of the Astronomican might function along the same lines of sailors staying within sight of land: It gives, beyond a vague reference point, a bit of a morale boost. If things get rough the sailors can just pop back to the land. Sure it might be full of angry natives or a lonely sandbar, but it's still a place where sailors can put their feet on dry land and think where they've gone wrong in lifeSomething much harder to do in the throes of a huge maelstrom or navigating without reference. As I recall, it was the dimming of the Astronomican that ground Lord Solar Macharius' crusade to a halt. By reaching the Halo Stars, the navigators were going out of sight of Holy Terra, and it scared the daylights out of them.

Its a very Terry Pratchett way of getting the point across.

CthonicProteus said:

That is bang on, if fact somewhere on the web is a map of the imperium and basically the reason why no one goes any farther is because they lose sight of the Astronomican.

With regards to what navigators do, in one of the black library books a navigator is close to the eye of terror on a rogue trader vessel and a warp storm they are flying around moves on them and they get caught inside and the navigator goes from seeing a 6 dimensional sense of the warp to a 15 dementional view. The navigator states that he is to young and does not have enough expierence and that even the very skilled navigators of the imperial navy would have a hard time with 15 demensions.

"By providing a single fixed point, the Astronomican forms a vital part of warp travel, allowing Navigators to effectively triangulate their position" - Rogue Trader core rulebook page 161.

Apparently they do triangulate >_>

Zelsior said:

That would be Farseer written by William King, part of a Eldar trilogy he never finished. Also despite the title the story is about a down on his luck rogue trader with a pressing problem...

Bassemandrh said:

Ah yes, but they triangulate in a place where a triangle can have 6 sides and 8 angles.

Regarding the OP question.

answers have been given as to how various races travel through space/warp but it leaves the question how they survive the trip without a Geller Field. and I'm not thinking of the eldar here as I suspect they do not need it in the Webway.

Quicksilver said:

And where those angles add up to a total of 704 degrees.