Reynard said:
So.....
Is there a consensus, with everything we're thrown out so far as well as the chaff, as to whether jump shadow/mask is important in Traveller 1st ed. according to the very limited references? So far it seems stellar bodies don't effect travel between stars. Mostly the effect would be stars and gas giants with large shadows reaching potential destinations worlds once ships arrive in system. Problem is there are no sizes given in Mongoose Traveller for larger bodies to judge intra-system travel due to huge shadows. Does this mean it's pretty much a plot device for the referee to color a scenario?
To the original question, I never bother simply because there is so little information to use it. Even traversing the 100D of a destination world is a quick glance at the Interplanetary Transit Times Table. The rest is a bee line to a nearby world or gas giant. You'd need a bigger book (about 759 pages worth) to pack all that information to really make use of shadows.
Jump Shadowing and Jump Masking are
logical consequences of the described Jump Mechanics. While they may be ignored for the sake of gameplay,
reason dictates that
they exist, since the masses of
all objects are treated
the same by physics, and so the mass of a planet
can’t somehow be
more relevant than the mass of a star. Stars with diameters that are relatively large compared to their habitable orbits
will bring ships out of jump at a distance of 100D of the star, even though the
Intended Destination is more than 100D away. A big gas giant’s 100D range physically eclipsing the 100D range of a target object in the same system along
all possible Jump Trajectories into the system
will bring ships out of jump 100D away from the gas giant, and
not 100D away from the target object. Summed up, a ship must Jump and Precipitate at greater than 100D away from
all objects, or suffer corresponding penalties.
Do Mongoose, or other editions of Traveller, provide you with enough information to correctly model these things? No, no they don’t.
For starters, you need to know at what angle to the Destination System’s orbital plane your ship’s available Jump Trajectories must approach at; it’s a perfectly Euclidean straight line from one Jump Point to another, so the available options for drawing that line from the Initial 100D Sphere to the Destination 100D Sphere are dictated by this angle. Also important is
knowing where in the target system those objects will be, so you can determine whether one thing or another is Shadowed, Masked, or whatever, by something else. This is where all the rambling about Orbital Navigation comes in... a properly plotted jump is going to consider the navigational advantages and disadvantages of
where in the target system you
intend to pop out at. As such, you have to know
all the positions of the planets
in advance; not just to calculate the jump
at all, but to calculate
where exactly in the target system you want to
enter, for minimum travel time. So, Traveller is currently missing...
1. The angle of the primary orbital plane of a given system relative to the Jump Map
2. The planetary orbit information of
every object significant to Jump Navigation within that system, so you will know
where planets in the target system will be
when
This makes GMing such a game realistically highly problematic, unless you have some very nice tools to help you. Number 2 is conveniently covered by some online tool whose address I have misplaced... you feed it a date, and it tells you where everything is for that planet; very nice. But number 1 is a detail that
should be canon that
has never been covered.
The likelihood of intermediate hexes providing any
meaningful masking between the and the Initial System and Destination System is
astronomically slim... practically speaking, it should be ignored, except as an excuse for plot devices, or as a trick available to players post-discovery.
So how should this stuff play out in game? Well, it depends on how you want your games to go... If the fun in your game is
not in how your players get there, just ignore it all. But if your players would prefer to sweat the details of Jump Navigation and Orbital Mechanics to shave a few hours (or even days) off of travel time in the Initial or Destination systems, go for it. A clever Navigator can plot a Jump Trajectory that, upon exit, will slingshot you around a planet onto the course of your destination faster than a raw burn alone. If that sounds fun to your players, use Jump Shadowing and Jump Masking in your games to give your players interesting Navigation puzzles to solve. But if they’re simply
not into game mechanics derived from realism,
just don’t.
