Jumps, Time to Orbit, to 10D and 100D

[aramis]

IMTU, Jump masking and jump shadows of intervening objects don't count; your entry point and exit point ONLY matter. You can enter from within a shadow, but if your exit is within a shadow, you are displaced to the surface of said shadow. Masking only applies in as much as your destination might be inside the star shadow, the planet shadow, or in regina's case, the GG's shadow.

Vectors: IMTU, a vector CAN be retained, and it's related stellar and planetary positions (Ray from largest Jump shadow to second largest Jump shadow being the reference point for vector). Excess velocity is corrected by the jump-space travel.

But , to get a "Bingo Jump", one MUST have been goingin the right direction, and exit at the right point.

 

[mike wightman]

OH NO,
someones mentioned jump masking and shadowing, here we go again

Seriously though I think people have to realise that MWM has authorised the GURPS version. But do not be down-hearted. In much the same way as a computer is obsolete as soon as you sign for it, once you start your first adventure in the(many) Traveller OU(s) then it becomes yours, do with it what you will

I personally have always done it much the way Aramis sets it out except all velocity is retained after jump, well it is a vector quantity afterall

 

[Hal]

Originally posted by Sigg Oddra:
OH NO,
someones mentioned jump masking and shadowing, here we go again

Seriously though I think people have to realise that MWM has authorised the GURPS version. But do not be down-hearted. In much the same way as a computer is obsolete as soon as you sign for it, once you start your first adventure in the(many) Traveller OU(s) then it becomes yours, do with it what you will

I personally have always done it much the way Aramis sets it out except all velocity is retained after jump, well it is a vector quantity afterall

For the record, I myself use the concept that the 100 diameter rule only applies to entry and exit from jump space. And here is why. Things move in our universe (gasp!). What was an ok route today may not be an ok route tomorrow, and then 1 hour later, be an ok route again! This means that misjumps can occur far more often. In the original Traveller Universe (CT style) Misjumps via a ship that has always kept up its maintenance repairs, always uses refined fuel etc, has *NO* chance of a misjump.
Also - I don't use the "variable" jump space timing either. If you miss your jump entry and/or exit by X amount of time, then the combined movements of the star of that system plus the planets of that system will make for some real "headaches".

The only way I can see where a person might exit improperly from jump space someplace other than where they intended, should be based on the navigational computations made by the navigator. Sort of like when you fire a gun. You may pull the trigger properly, and you may be more or less aimed in the right direction - but if your aim is bad, you miss by how badly you aimed. If your hand is shaky, you miss by how much your hand was shaky at the moment you fired and so on.

I guess the best way that I LOOK at it is thus:

Make your navigation roll properly, and you jump as intended to where you want. Miss by 1 or so, and you're more or less in the right ballpark. Miss by too much, and you won't be in the right ball park even. Crit fail (or spectacular failure or what ever you want to call it) and you ain't in Kansas no more Dorothy!

 

[Straybow]

Everything I've seen about jump calcs, from masking to velocity matching, seems to ignore the fact that orientation of eccliptic planes is random. Centauri system has two large stars defining a primary eccliptic plane which is tilted from our perspective here in Sol system. The exact data is known to modern astronomy.

AC is visible from the southern hemisphere, and the angle of the chord relative to Sol's eccliptic is also known.

The chord between the stars will almost always have a high angular displacement from the eccliptic of the target system. Instead, you must move in a vector out of the eccliptic of the originating system if it is to be useful relative to the target system.

Maybe jump space has very little to do with real space, when Solomani left earth and jumped to Centari matbe it was a 1J jump, They where flighing an experimental craft so they realy didnt want to try it deep in the grav well so they flew it out past neptune or pluto to try it.

Well, Neptune and Pluto are out around 30-36 au. One light year is ~63,113 au. If the "hard" limit is 3.2 light years, you would have to make up at least 1.2 light years at some pathetic speed that would require decades.

"In the way" is defined as being within about 60 degrees of the intended path and closer.

TheDS, that means you are projecting the masking out to ~1 parsec, which means jump would never work at all. When looking at interstellar distances 100D of any star is insignificant. A red supergiant may have D = 10 au, so that 100D is 1000 au. From 1 parsec away the angle is asin(1/(63·3.2)) = 0.28°. I suspect the line you draw on the map is thicker than that angular deviation, so if the line isn't touching the intervening star in three dimensions, it isn't "in the way."

 

[TheEngineer]

Hi,

ever thought of a jump plot that is not just simplified straight (whatever that is in the universe..) but also somehow curved, in order not to hit any 100D limit ?
Just navigate around obstracles.

Besides, is there anything official saying that a jump plot is straight anyway ?

Regards,

Mert

 

[robject]

Originally posted by TheEngineer:
Hi,

ever thought of a jump plot that is not just simplified straight (whatever that is in the universe..) but also somehow curved, in order not to hit any 100D limit ?
Just navigate around obstracles.

Besides, is there anything official saying that a jump plot is straight anyway ?

Regards,

Mert

An intriguing and useful thought. And no, there's nothing that says a jump has to be a straight line (I think)...

 

[kaladorn]

The schools of Jump Masking and Jump Shadowing suggest (or one of them does anyway) that a jump must be direct because it uses the fact that a planet or other body in the system other than the origination or destination can occlude the jump path.

There ought to have been some big threads on this a month or two back here on CotI...

 

[TheEngineer]

Hi Thomas,

yep, but thats the style:

Lets find a problem and define a reason for that

=)

I also remember the COTI discussion You have mentioned...

Really, I found no source in my CT/MT/TNE stuff or this pretty MWMs "Jumpspace" article that suggests the kind of simplistic view of a "straight" jump plot.

Curved jump plots just offer a greater flexibilty in navigation and still consider most of the masking/shadowing effects of large bodies....
But they take out the variable of the geometric relationsship between different planetary systems...which I really would not like to track.

So, I guess they peacefully can live side by side

Best regards,

Mert

 

[The Oz]

The major reason I like jump shadowing/masking is that it often winds up requiring PC ships to spend more time in normal space getting clear of a star's jump shadow before they can jump to their next destination. And that gives more time for the pirates to show up....

 

[Flynn]

I always thought jump masking was based on the emergence point, not paths as defined in terms of normal space. If the emergence point ended up within a 100 diameters of some material object, the point was displaced to the nearest point in space which was 100 diameters from any material objects in the vicinity. Because of the shift, the emergence was often rough, as like a misjump.

However, this was my concept, or an IMTU thing, and should not be considered official. But it works very well, and disregards the jumpspace-normal space correlation issues.

Two more creds,
Flynn

 

[TheEngineer]

Hi !

@The Oz:
Evil gamemaster...

Yep, I like deep gravity well situations, too.
Helps reducing uncontrollable player moveability

@Flynn:
I always thought "running against the gravity well" is the standard method of bad pilots/astrogators to get near to the destination

BUUUUUMMMMMMMMPPPPPPP
Pilot: "Ehhh, here we are..."

Regards,

Mert

 

[The Oz]

Originally posted by TheEngineer:
Hi !

@The Oz:
Evil gamemaster...

Thank you. I try.

 

[rancke]

Originally posted by Flynn:
I always thought jump masking was based on the emergence point, not paths as defined in terms of normal space. If the emergence point ended up within a 100 diameters of some material object, the point was displaced to the nearest point in space which was 100 diameters from any material objects in the vicinity. Because of the shift, the emergence was often rough, as like a misjump.

That's how it used to be. But jump masking has been added and officially approved by Marc Miller, so that's how it is now. In the OTU, at least.


Hans

 

[mike wightman]

So does that mean all rules varients introduced in GURPS Traveller are now canon or only the select few
How do we find out which are setting only rules and which are now canon

 

[TheEngineer]

Hi,

thats the kind of effect, when rulesets, basic mechanics and background data are mixed...
So we will have to buy all the products available in each Traveller product line in order to be up to date with canon ?

Is there also something said about jump plot geometry in G/T?

Regards,

Mert

 

[Badbru]

Something slightly off thread, and for which I apologise in advance for but it's been plaguing me for years.. Is there anything in "canon" that makes a ruling on jumping into empty hexes, deepspace, not a solar system??? I allways thought, and prefer to play, that you can't, that you need the gravity well or atleast the navigational points of reference ie the big star in the middle. Any opinions/rulings/IYTU workarounds?

 

[The Oz]

I remember references to "deep space refueling points" for things like crossing the Great Rift and such, but I can't remember off-hand if those were built around available masses or not.

IMTU, I do allow exit of jumpspace at any point not within 100D of a massive body, so exiting in deep space is just fine.

 

[mike wightman]

Badbru asked:

Is there anything in "canon" that makes a ruling on jumping into empty hexes, deepspace, not a solar system???

Yes , there are a couple. Perhaps the most valid one is the Traveller Adventure which includes a scenario where the crew of a Fat Trader have to get demountable tanks so they can make the jump into an empty hex and then on to their destination.
In the same Supplement there is a scenario where several ships lie in wait to ambush Tukera ships at a refueling stop built in an empty hex.
Hope this helps.

 

[kaladorn]

Point One:

Jump Masking vs. Jump Shadowing
These two differ. One says "endpoint of jump might be inside of another gravity well, thus you come out early", the other says that plus "and massive bodies may get in your way, further complicating your travels including forcing you to spend more time to get a clear shot at the target, or precipitating you out if you pass to close to a significant mass".

GT assumes the latter, IIRC, based on Marc's article and some conversations between citizen Thrash and MWM.

CT (originally) was sort of the former, but MWM can be considered a canon setter for CT/MT setting, so I'd say that we can consider the latter case to now apply, even if not well documented.

As to what is canon, that'd depend on if you mean GURPS Traveller canon, Classic Traveller Canon, MegaTraveller Canon, TNE Heresy Canon, 1248 Canon, T20 Millieu 0 Canon, or what.... <in other words, you pick based on what universe and I guess your own proclivities or just go with 'latest ruleset'>

Now, you can jump into deep space. The reason it happens not often is because you can't often carry enough fuel to get back and there is very little economic benefit for this kind of jump. But it can be done, with short jumps from a ship with a big fuel tank (this is something that has changed too.... in some versions of Traveller, a jump consumes X amount of fuel related to how far you are jumping, in others, it is Y amount of fuel related to the jump rating of your drive and invariant with distance - the latter being an older official take on things from MWM, but the former being far more useful....).

 

[Richard Saunders]

Hello.
My take on jumping into empty hexs - You can do it but it takes a lot longer to find your current position, In a system you know exactly where the planets are and you can mark them with your sensers, For triangulation. In open space you need to mark a minimum of four stars that you have specrums for for the same thing, This will take longer. You realy dont want to jump blind (I work that its the time in jump space that determinds when you come out and the time is veriable because of gravity changes in normal space while you are in jump space).
All trips in jump space must be straight line movement (except for distortions because of gravity or the monsters in jump space (something changes otherwise all trips on any single run would have to be the same time))If you program course changes in jump space how do you time the changes (the time variation for every trip could kill you) and if there are things in jump space you could navigate of (tho this would exsplane the missing mass from the universe)do you want to try it, has anyone seen a map og jump space (wonderful job for the IISS and i'm sure they will thank me for this idea).

Bye.