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Jump destination

Posted: Thu Apr 19, 2012 8:20 am
by dzanis
Hi, everyone,

I can't find information about how you know where you arrive after Jumping. On page 141 of rulebook it says: When the ship exits Jump space after an accurate Jump, it tends to arrive close to the target world, but outside or on the verge of the hundred-diameter limit.

and here are my questions:
Can you choose which planet to Jump to? (if i want only to refuel, I jump to Gas giant not the habitable planet)
Is it meant that through astronavigation calculations you actually can choose more or less precise point where to exit Jumpspace (tkaing into account planet movements and such?)
What if i want to arrive in asteorid belt or relatively nearby it? I mean, is there a detailed information avalable on ships about movements and gravities orbital velocities of thousands of asteorids?

Re: Jump destination

Posted: Thu Apr 19, 2012 8:30 am
by far-trader
Quick answers:

Can you choose which planet to Jump to? (if i want only to refuel, I jump to Gas giant not the habitable planet)

Yes.

Is it meant that through astronavigation calculations you actually can choose more or less precise point where to exit Jumpspace (tkaing into account planet movements and such?).

Yes.

What if i want to arrive in asteorid belt or relatively nearby it? I mean, is there a detailed information avalable on ships about movements and gravities orbital velocities of thousands of asteorids?

Yes. (at least the major ones)

Re: Jump destination

Posted: Thu Apr 19, 2012 12:53 pm
by Rikki Tikki Traveller
In one of the older versions of Traveller, the game's creator stated that Jumps were accurate to about 3000 km.

Personally, I think that is too accurate, but you can use whatever you want in your game.

The impression from the core book and HG is that you can jump anywhere you want outside the 100D limit.

So most ships jump just outside the 100D limit of the planet they are heading towards. For some worlds, they have to jump to the 100D limit of the star but still, they go to the closest approach to the planet and then Maneuver in from there.

Re: Jump destination

Posted: Thu Apr 19, 2012 2:04 pm
by dzanis
Thank you both. So simple and precise jumping...

Re: Jump destination

Posted: Thu Apr 19, 2012 4:56 pm
by Egil Skallagrimsson
dzanis wrote:Hi, everyone,

I can't find information about how you know where you arrive after Jumping.
Look out of the window? :)

Otherwise what far-tradersaid.

Egil

Re: Jump destination

Posted: Fri Apr 20, 2012 1:55 am
by Vargrz
In most of the adventures I run, the jumps are fairly accurate and the players choose before the jump (and the dice rolling) which planet in the system they are aiming for.

Re: Jump destination

Posted: Fri Apr 20, 2012 7:34 am
by locarno24
Yup, in theory (at least for a 'mapped' system) you have a pretty accurate chart and can jump wherever you like. It's only the week-duration-regardless-of-range which stops jumps being the preferred method of getting to remote planets; nothing stops you making an intra-system jump if you want.

The key restriction on jump locations is the 100D of large objects; you can therefore expect that anything whose 100D region is of significant size (big comet, moon, lagrange point station, etc) will be on the chart.

Note that asteroids are the big unknown; there will be a survey programme of this sort of thing done - I assume by the scouts - on a fairly regular basis. However, a newly colonised world, or a world which doesn't rate scout survey (a non-imperial world off the trade routes) may well have an incomplete or outdated object catalogue. Which can lead to deeply unpleasant experience. Of course, the odds of a jump path intersecting the 100D of even a massive comet is so close to zero as makes no odds, and obviously no GM would ever have an unfortunate misjump crash the ship out of jumpspace inside the comet's tail, with fragmenting chunks of rock and ice tumbling past them the instant the jump bubble pops...that would just be mean. :mrgreen:

Re: Jump destination

Posted: Fri Apr 20, 2012 12:19 pm
by dzanis
locarno24 wrote: Note that asteroids are the big unknown; there will be a survey programme of this sort of thing done - I assume by the scouts - on a fairly regular basis. However, a newly colonised world, or a world which doesn't rate scout survey (a non-imperial world off the trade routes) may well have an incomplete or outdated object catalogue. Which can lead to deeply unpleasant experience. Of course, the odds of a jump path intersecting the 100D of even a massive comet is so close to zero as makes no odds, and obviously no GM would ever have an unfortunate misjump crash the ship out of jumpspace inside the comet's tail, with fragmenting chunks of rock and ice tumbling past them the instant the jump bubble pops...that would just be mean. :mrgreen:
As one esteemed author said something close to "those things that are highly improbable to happen with odds of one in ten million; in real life these happen nine times out of ten" :)

Re: Jump destination

Posted: Fri Apr 20, 2012 6:03 pm
by phavoc
A quick little rule of thumb works here.

Have the player roll a d6, whatever number they roll is how many thousands of Km's they are off from their point of entry. If they roll a 6, then roll again and add that to the total. Every 6 they roll means another roll.

Re: Jump destination

Posted: Sat Apr 21, 2012 11:09 am
by Reynard
Jumps are fairly accurate because of those honking huge ship's computers. Takes a lot of computing power to store all that stellar data then continuously calculate normal vector shifts of the system in general and all the known components specifically.

When a new system is to be surveyed, scout vessels sit in a nearby system collecting general information especially concerning the system's actual location at the moment. Remember what we see is from light produced in the past. Scouts will observe a system's distance and vector and calculate where it actually will be. That includes where it will be in a week's time. Very little will be known about the system's components so a jump is made well away from the core. Even today scientists are locating gas giants and very large planets so these will be known before jump. This is very useful for refueling consiterations.

Once scout vessels enter a new system all components are accurately catalogued. This data now allow other vessels to make jumps in system close to their target destinations.