Jumping while underway

[Condottiere]

As an example, if you're jumping from an empty hex to a neighbouring sun stuffed system, you could take visual readings, adjust for three and a half years drift, and you should be within a reasonable spherical error of probability.

 

[rinku]

Sure. Of the stars.

We may be going in circles a bit now.

Although really everything is going in ellipses...

 

[MasterGwydion]

Once the processing power is high enough then all of these calculations become easy. You are comparing a million datapoints to the extremely accurate model of Charted Space in your navigation software in seconds. The model knows where everything is supposed to be at any given time. Your sensors tell you where all of the stars are now and tada!

 

[Sigtrygg]

As regards to empty hexes, I tend to think that's more game mechanics driven.

The game doesn't want you to use them as short cuts for monoparsec starships, so it disallows it.

Empty hex jumps are allowed in every iteration of Traveller apart from GT:ISW.

I don't recall what the official explanation was, but I'll assume that means that jump drives need a large gravity well as some form of light house.

This was never an offivial thing, apart for GT:ISW.

Nowadays, that's somehow been overcome.

It was never a problem, apart from GT:ISW.

 

[Sigtrygg]

" One of the benefits of the jump drive is its irreconcilability: jumping is predictable. When known levels of energy are expended, and when certain other parameters are known with precision, jumping is accurate to less than one part per ten billion. Over a jump distance of one parsec, the arrival point of a ship can be predicted to within perhaps 3,000 kilometres (on larger jumps, the potential error is proportionally larger). Error in arrival location is also affected by the quality of drive tuning, and the accuracy of the computer controlling the jump; these factors can increase jump error by a factor of ten."

 

[Condottiere]

It's one of those mechanisms that surface occasionally, when the authorities want to prohibit a particular activity.

Another one would be, exactly where is the border between parsecs, so that I can jump to it, drive over, and jump again to the edge of the next parsec?

 

[CordwainerFish]

Although really everything is going in ellipses...

Not everything. Some things are going in hyperbolas (hyperbolae?).

(Yes, parabolas and circles are possible, but they require precisely the right trajectory and so can be ignored here.)

 

[Geir]

Not everything. Some things are going in hyperbolas (hyperbolae?).

eccentric hyperbole
(or whatever that crank on the corner is shouting)

 

[CordwainerFish]

eccentric hyperbole
(or whatever that crank on the corner is shouting)

I've always wanted to visit Hyde Park.

 

[Geir]

I've always wanted to visit Hyde Park.

The end is Nye!
That science guy
He strangled on his own bow tie
Now that sure makes me want to cry


(so sorry, I'll go back to my regularly scheduled court mandated therapy now)

 

[Condottiere]

misjumping is bad
mistimed by a tad
screwed a familiar miss

it made me sad
becoming my dad
the man I used to diss

 

[Fluffy Bunny Feet]

But cutting through all that, you will know where you are well enough to jump to a star's 100D, and maybe the rough vicinity of a planet. But be prepared to travel, Traveller.

This made me think. Why not link the location accuracy to the die roll for time? The longer you take the less accurate your location? Roll all 6's and you're millions of kilometres off, maybe 100s of millions if the GM wants to make it dramatic.

 

[rinku]

Once the processing power is high enough then all of these calculations become easy. You are comparing a million datapoints to the extremely accurate model of Charted Space in your navigation software in seconds. The model knows where everything is supposed to be at any given time. Your sensors tell you where all of the stars are now and tada!

It's not the calculations that are the bottleneck here, but the measurements. In order to reduce the error of your exact location you are going to need extremely precise astronomy. More data points are good, but a typical merchant starship is unlikely to be equipped to do this. But would be good to make a jump with a (relatively) large margin of error to the next system.

The key difference to jumping out of a system is that you have known local points of reference you can calibrate your precise position from (or rather, those reduce your margin of error enormously).

In an empty hex you have no local point of reference and can only rely on extremely accurate measurements of extremely distant objects. Even determining your actual vector is going to be tricky, although you would have legacy data to make an educated guess from

I'm more than happy for a survey scout or a specifically equipped warship in a fleet to get the job done quickly, though.

 

[Condottiere]

Lighthouses.

Or, I suppose, radio buoys.

 

[rinku]

If you want to cut through all of this, by the way, I'd suggest just imposing a Bane on the Astrogation roll when jumping from an empty hex. Reduces the likely quality of the plot without imposing unrealistic penalties.

 

[Fluffy Bunny Feet]

I add 6D to the time variable if the location being jumped to OR from is unsurveyed and any empty hex location is probably going to be classed as unsurveyed.

 

[boggo2300]

If you're using the Jump Emergence deviation table from Companion, you can end up quite a way from the 100D emergence poiint...

 

[rinku]

Yep.

Combine that with a Bane for only roughly knowing where you are, I think the mechanics are good.

 

[Condottiere]

If the route is jumped regularly, you'd think that statistically the odds of a misjump, or deviation, minimize.

Even better, if the crew did the route regularly, in the same starship, which would further minimize variables.

 

[rinku]

Mmm. I wouldn't think so, statistically. Each jump will have its own variance and the difference between "no one has been in this super deep space location before" and "twelve crews passed through in the last week" isn't much.

However, if it is a heavily trafficked route someone might well set up some kind of navigation thingy that knows where it is. Up to and including a station with (expensive) fuel...

Deep Space Ten.