I object to the subtexted implications of your wording, but agree that different explanations work for different group dynamics. Suspension of disbelief is also an interesting & important subject in a game, particularly one like Rogue Trader, as different groups with different backgrounds are going to be able to accept different deviations from "normalicy"

I've known people who just can't handle non-neutonian realspace propulsion (no matter how much semi-scientific technobabble you throw at it) and others who are trying to figure out how much 'programing' is in a servitor. It all depends on player (and to an extent gm) background, both in real-world and in their literary experiences.

Ultimately, we're dealing with a semi-fantastic universe attempting to do things we can only attempt to imagine, much less explain or devolve logically. With enough effort, one can construct a 'logical' framework to support nearly any conclusion.

Another thing Quick, is the whole bit about currents and eddies in the Warp. An astropath, maps, and anyone with the Navigation (Warp) skill IS good enough for those short jumps, but it doesn't suffice for the longer ones. I don't see how a timepiece is going to nullify a shift or twist in the warp current, and that's where the Navigator comes in, that and those longer jumps.

And yes, it's all about suspension of disbelief. I thought that went without saying. And, some groups want specifics while others are good with a hand-wave. I'm always ready with the specifics, though. My last group included some gear heads. I have a chart with random adjectives and nouns that I can randomize with dice and apply to any piece of machinery on their vessel and sound very plausible. I stole a page from another game for that trick. You don't think I think every last thing through, do you?

If you found something objectionable, object to the originator of the undertone, not its responder. I didn't grow up in the I'm-Ok-You're-Ok-We're-All-Ok generation.

I don't see an Astropath as necessary for those short jumps. If your only talking about 4-5 lightyears, it's going to be easy to see where you ended up when you arrive. All it really takes is a Map and someone with the skill to read it. (i.e., Navigation(Warp)). The map will tell you the way the currents in the Warp are supposed to be going so you can aim accordingly. If they've shifted, you'll end up somewhere different, and plan your next jump accordingly.

I agree that a Timepiece isn't going to allow for any longer of jumps. But I don't see it having any particular navigational use at all in this setting. You needed it in the Age of Sail because relative time indicated degrees from Prime Maridian. There is no 'local time' to compare against when your floating in space, nor would it tell you anything if there was.

Navigators are, of course, critical for watching out for shifted currents, eddys and Warp Shoals, being the only ones who can look into the warp and see them makes this clear. But you wouldn't need the Astronomicon if they were glorified crow's nest look-outs. It seems safe to assume, then, that they are doing in-warp navigating based on the Emperor's Great Lighthouse and anything else they can see.

That was the chart I was vaguely remembering, thank you.

The Imperium has existed for 10,000 years though, and Terra has been presumably beaming out signals for about 39,000 years so someone sensible - which I remind you are almost never the people in power - could have worked something out by now. At the very least the Segmentum Solar could have been put on reliable Terran Standard Time.

I'm really tempted to try to flesh out a group of Pilgrims who do nothing but ride through the Warp to try to hear a message from the Emperor over and over again, and that message is just the Emperor reading out the time and giving some information for Adepts to set their watches by.

Or ships of Adeptus Mechanicus, which are located within a radius of 38,000 light-years from Terra and take radio and TV broadcasts from Earth with all their scientific and educational programs

That was the chart I was vaguely remembering, thank you.

The Imperium has existed for 10,000 years though, and Terra has been presumably beaming out signals for about 39,000 years so someone sensible - which I remind you are almost never the people in power - could have worked something out by now. At the very least the Segmentum Solar could have been put on reliable Terran Standard Time.

I'm really tempted to try to flesh out a group of Pilgrims who do nothing but ride through the Warp to try to hear a message from the Emperor over and over again, and that message is just the Emperor reading out the time and giving some information for Adepts to set their watches by.

Or ships of Adeptus Mechanicus, which are located within a radius of 38,000 light-years from Terra and take radio and TV broadcasts from Earth with all their scientific and educational programs

Not quite that far. After all, while we're radiating a whole bunch of EM, it's being radiated in a sphere, and dispersed/diffused over distance. To pick up something from Earth's early transmissions at that kind of distance would probably require a rather large array of monitoring stations. Admittedly, you're on the right track with the AdMech, but anything sensitive enough is going to be too large to be particularly mobile.

Forgeworlds, Knightworlds. Anywhere the AdMech sent slowboats to before the Emperor's Reunification of Terra, they'd be able to synch perfectly with math. Anywhere settled by a slowboat should have been perfectly synched, so any of them that retained culture/tech.

Not quite that far. After all, while we're radiating a whole bunch of EM, it's being radiated in a sphere, and dispersed/diffused over distance. To pick up something from Earth's early transmissions at that kind of distance would probably require a rather large array of monitoring stations. Admittedly, you're on the right track with the AdMech, but anything sensitive enough is going to be too large to be particularly mobile.

Not quite that far. After all, while we're radiating a whole bunch of EM, it's being radiated in a sphere, and dispersed/diffused over distance. To pick up something from Earth's early transmissions at that kind of distance would probably require a rather large array of monitoring stations. Admittedly, you're on the right track with the AdMech, but anything sensitive enough is going to be too large to be particularly mobile.

Stations will be positioned only in the plane of the galaxy - no one loves the deep void. And stations can be organized on the principles of Space Very Long Baseline Interferometry (SVLBI), i.e. each "station" will be of a three or four specialized ships (AdMech's equivalents of a Viper-class scouts with two or three X-470 Ultimo arrays, servitor crew, etc.) per star sistem.

Pretty sure stations w/ distributed satellite arrays would be more effective/efficient than using ships. Then again, it is 40k.

when I DM RT, the navigators know the true time.

in the vast hall of the Astronomican, where the psykers sit to backup the Emperor's signal,

a complex song is always playing in the background.

The symphony has 12 movements, each movement takes 30 days to play through, and

the movements are divided into 24 stanzas, each stanza takes an hour to play.

For the extra five days left over, a special song is played leading up to Emperor's Ascension day.

Then the symphony repeats all though next year.

So when the Navigator feels the location of Earth for the Astrogation, all he has

to do is think for a moment on what snippet of the song was playing in the background.

and he can tell what hour/day/month it was on earth when he fixed his plot.

they then punch a little code into a cogitator, and the time gets updated

to the astropaths, captain's log, the bridge, and other parties on the ship.

In addition, the peaceful and meditational aspect of the song irritates daemons who can hear it.

I like that idea Egyptoid.

Only problem with that is it doesn't get you the year. Maybe there are variations based on year.

You can just send a signal through materium from a node (such as a Forge World) and do a fairly simple math to calculate the time from that point. Combine it with natural events such as supernovas and you can have the clocks synchronised to a really good (hours diffrence good) degree in under a 100 years across the whole Imperium.

Also, most human planets that remember the Dark Age of Technology are very likely to have extremely accurate time measurement counted from The Fall of Eldar.

when I DM RT, the navigators know the true time.

in the vast hall of the Astronomican, where the psykers sit to backup the Emperor's signal,

a complex song is always playing in the background.

The symphony has 12 movements, each movement takes 30 days to play through, and

the movements are divided into 24 stanzas, each stanza takes an hour to play.

For the extra five days left over, a special song is played leading up to Emperor's Ascension day.

Then the symphony repeats all though next year.

So when the Navigator feels the location of Earth for the Astrogation, all he has

to do is think for a moment on what snippet of the song was playing in the background.

and he can tell what hour/day/month it was on earth when he fixed his plot.

they then punch a little code into a cogitator, and the time gets updated

to the astropaths, captain's log, the bridge, and other parties on the ship.

In addition, the peaceful and meditational aspect of the song irritates daemons who can hear it.

This is one great idea but I personally don't like the thought of Astronomican is galactic timepiece. Terra or not, the psychic choir is broadcasting through warp which is not reliable time-wise. Time itself is inhomogenously in immaterium, warped and twisted.

So, despite being a choir and music, I think all Astronomican is useful for is for checking your direction.

Of course, one can always say that the Holy nature of such a beacon stabilizes temporal aspect of warp...

when I DM RT, the navigators know the true time.

in the vast hall of the Astronomican, where the psykers sit to backup the Emperor's signal,

a complex song is always playing in the background.

The symphony has 12 movements, each movement takes 30 days to play through, and

the movements are divided into 24 stanzas, each stanza takes an hour to play.

For the extra five days left over, a special song is played leading up to Emperor's Ascension day.

Then the symphony repeats all though next year.

So when the Navigator feels the location of Earth for the Astrogation, all he has

to do is think for a moment on what snippet of the song was playing in the background.

and he can tell what hour/day/month it was on earth when he fixed his plot.

they then punch a little code into a cogitator, and the time gets updated

to the astropaths, captain's log, the bridge, and other parties on the ship.

In addition, the peaceful and meditational aspect of the song irritates daemons who can hear it.

This is one great idea but I personally don't like the thought of Astronomican is galactic timepiece. Terra or not, the psychic choir is broadcasting through warp which is not reliable time-wise. Time itself is inhomogenously in immaterium, warped and twisted.

So, despite being a choir and music, I think all Astronomican is useful for is for checking your direction.

Of course, one can always say that the Holy nature of such a beacon stabilizes temporal aspect of warp...

On the one hand, yes, the Warp is unreliable and does bad things to time ... on the other, the highest temporal reliability rating you can get outside of being in the Sol system itself is being in direct psychic contact with the Sol system.

So, I'd say that the Astronomicon can probably ignore or override the temporal instability of the Warp the vast majority of the time.