^ speaking of. I was interested to see how the Manual handled jumps into Jumpspace. In a couple of different ways.
In my rather short time and experience playing Traveller as I learn the ropes of the game I've made extensive use of both Travellermap.com and the wonderful Traveller Tools II website yet was quick to notice they have very different calculations of 100D. One took into account the (far greater) 100D of the star, the other just used the main planet's thus had wildly different times out to 100D. I sort of figured based on common sense and enough semi-remembered education to go with the star's diameter. Nice to see the Manuel sort of confirm that was the right thing to do.
The other thing I was curious about. Jump Masking. While I've been dancing on the head of a pin balanced keeping the wife happy (which is directly proportional to paying the bills) with buying up Mongoose Traveller books as quickly as a I can haha I'd also been snagging up the Gurps Traveller resource books (the Nobles book is a killer. Love that book) off of ebay. The first I got naturally was Far Trader that had a rather wonky ( and very unintuitive to me) chart for calculating Jump Masking. Yet unless I completely missed it, the Manual did not go there at all. I'd be curious to hear why the writers/creators of the book didn't go there and explore that topic with the book. Too much crunch for too little flavor??
(or has it been covered in some other book, one I haven't got yet? Like Matt pointed out to me when I was looking for a sector book on Corridor sector)
Not a criticism mind you, just asking more of curiosity.
Masking is definitely a thing. I believe it was first explicitly introduced by
GURPS: Traveller (I may be misremembering), but it is definitely in T5, so Marc Miller definitely considers it as canonical.
Basically, when
Classic Traveller first came out, there were no rules for star system generation, just world generation. So all 100-D limit calculations were based off of planetary diameters in the UWPs. When
CT Book 6: Scouts came out detailing Star System generation, now all of the bodies in a system could be detailed, all of which had 100-D limits. Of course, not every GM and campaign (or at least not every adventure) was dealing with a star system mapped to that detail, and there was not as yet canonical info on the primary star data of every system like there is currently on
Traveller Map and/or the
Traveler Wiki, so not every GM wanted to deal with that level of hassle, especially if they were going to have to detail it themselves from scratch for every system their Traveller-group visited. So many ignored 100-D limits for anything except the mainworld for simplicity's sake.
Jump-Masking added another level of complexity. Now one needed to be concerned about the current
orbital configuration of all of the bodies in a star system at any given moment (and they are always changing), because the Jump-shadow of any one of them
might be blocking the clear jumpline path to your destination (especially companion stars) and require a period of normal-space maneuvering to get you into a position from which you can get a clear line-of-sight path to your jump destination that did not intersect another body's jump-shadow. It also required a knowledge of the complete star-system configuration for any jump for which it was going to be relevant. Again, most GMs did not necessarily want to deal with this level of complexity as a matter of routine "every-time-you-jump" hassle, and so just used the 100-D planetary limit and assumed everything else was in order.
As a side note, remember that space is (obviously) 3D, so not only will potential jump-destinations actually be distributed about your ship in a
spherical distribution relative to the originating system (i.e. the target system will not necessarily lie in the plane of the originating system's ecliptic), but that the orientation of the
target system's ecliptic will also likewise not be orientated at the same angle as the originating system's ecliptic (i.e. the two ecliptic planes won't necessarily be parallel - they can in fact be inclined relative to one another at any angle in a 360° spherical orientation). Getting out around a "jump-masking" situation may be as simple as heading "
due North" or "
South" (i.e. "
upward" or "
downward") from the ecliptic plane on M-Drive thrust.
Having said all of this, I think all of the above creates the potential for very flavorful campaign elements and specific adventure-challenges for the GM who is willing to put in the time to do the necessary system-construction where relevant. For example, the simple "job" becomes much more complex when the party gets delayed or otherwise held up for several days or a week or more, and now the simple "quick" jump out-system to the buyer (or away from the adversary to the patron) is hampered by the system companion star whose jump-shadow has just begun to occlude the jumpline, requiring a 3-day system maneuver to get into a good jump-position. Jump-masking can also create "seasons" in a particular system when traffic from a certain direction cannot get to its destination as easily or quickly as other times, which may have commercial or strategic ramifications.
Stellar jump-shadows and masking also create some interesting local situations. For example, the Jump shadow of a Giant star is immense, yet there are some inhabited planets that orbit such stars well within the stellar 100-D limit. What is the society like on a world where outsiders need to travel 70
days by maneuver to get to your world after jump break-out due to your primary's 100-D jump-shadow? Why would anyone want to go or trade there? What trade or adventure opportunities would it create, since nobody really
wants to go there?
In the end, the old
Traveller principal applies: "
Do-Only-As-Really-Necessary". Bring in the Shadowing and Masking when it is useful for the adventure at hand, or for a particular designed adventure plot, and skim over it when not (i.e. assume it happens in the background, give a quick description when necessary, and move on). Don't feel you have to give the nitty-gritty details of everything that happens along the way unless they are somehow meaningful to the adventure or the campaign as a whole.
In general, the highly detailed system approach and detailed shadows and masking tend to work best in a campaign of limited astrographic scope (one that will operate only over a few systems or part of a subsector), where the characters are returning to the same systems on a regular basis. A wide-raging campaign across subsectors in which players will likely only encounter most systems only once probably doesn't need that high level of detail, except where really needed for a particular adventure.
