Everything I know about Jump I learned from MWM

[captainjack]

I have to agree with fusor here. First Antares has to capture a rogue world and then someone has to terraform it. Much as I try to use the Ancients as little as possible, I think they're needed here.

Or possibly the capture could be a natural (albeit low-probability) event and the Vilani could have done the terraforming. Or a mysterious, otherwise unknown civilization. If the blackbody radiation really is -90 degrees Celcius, then the Ancients probably didn't put the world in that orbit -- they'd have put it a bit closer to the star, close enough to give it Droyne-compatible temperature.


Hans

It seems certain that the planet isn't the one formed with the star, so either a low probability capture or an actual move is required. Beyond that, how far out can it be (ie how much closer to the jump limit) given how cold it can be? The only real limits seem to be that the O2 isn;t frozen out for it to rmain consistent with its UPP.

Having a standard atmosphere suggests that either its terraformed, but why then is it so cold, or that it is a capture, and it was originally a oxygenated atmosphere planet; which suggests that it originally was around another star wandered around & froze out, then arrived here, and has been thawing out enough to have its original atmosphere, without the life (presumably).

Regardless, it's a fascinating anomaly to wrap a story or adventure around, if not an astrophysics article..

 

[fusor]

I'm really not interested in bickering about this or responding to trollish comments. I've shown how going to Antares' mainworld from the star's jump limit can only be done by sublight drives if jump shadowing (or whatever you want to call it) exists, and that the voyage takes many weeks. That has to be explained/accounted for in a realistic setting.

If people just want to ignore that here though, I'll stop wasting my time on this thread.

 

[far-trader]

I'm really not interested in bickering about this or responding to trollish comments...

:rofl:

 

[captainjack]

I'm really not interested in bickering about this or responding to trollish comments. I've shown how going to Antares' mainworld from the star's jump limit can only be done by sublight drives if jump shadowing (or whatever you want to call it) exists, and that the voyage takes many weeks. That has to be explained/accounted for in a realistic setting.

If people just want to ignore that here though, I'll stop wasting my time on this thread.

Oh, surely you would not throw us in the briar patch ? That would certainly teach us a lesson, sir.

 

[mike wightman]

I have to agree with fusor here. First Antares has to capture a rogue world and then someone has to terraform it. Much as I try to use the Ancients as little as possible, I think they're needed here.

Or possibly the capture could be a natural (albeit low-probability) event and the Vilani could have done the terraforming. Or a mysterious, otherwise unknown civilization. If the blackbody radiation really is -90 degrees Celcius, then the Ancients probably didn't put the world in that orbit -- they'd have put it a bit closer to the star, close enough to give it Droyne-compatible temperature.


Hans

Not the Ancients again, they have been done to death; but I like the idea of an old, unknown, civilisation doing the world engineering.

It's given me the idea for a campaign.

 

[aramis]

I'm really not interested in bickering about this or responding to trollish comments. I've shown how going to Antares' mainworld from the star's jump limit can only be done by sublight drives if jump shadowing (or whatever you want to call it) exists, and that the voyage takes many weeks. That has to be explained/accounted for in a realistic setting.

If people just want to ignore that here though, I'll stop wasting my time on this thread.

The above looks rather trollish from here... at least as much as any of the posts.

No infraction from me, but, please, do us all a favor and follow through. Some of us prefer to see the potential for adventure oportunites rather than hear constant wet-blanketry.

Many of us look for how to make it work, rather than looking for reasons it doesn't.

 

[fusor]

Some of us prefer to see the potential for adventure oportunites rather than hear constant wet-blanketry.

Many of us look for how to make it work, rather than looking for reasons it doesn't.

I think that's all very much a matter of perspective, isn't it?

I see adventure (and discussion) potential in discarding any existing canon about this system and exploring the potential consequences (economic and physical) of requiring 1-3 months (or more) of sublight travel time to get to a mainworld deep within the 100D limit, or of having an entire hemisphere of jump routes blocked off for hundreds of years by a supergiant's jump shadow if the mainworld orbits a companion star outside it.

What you call "wet-blanketry" is what I call "acknowledging reality" - I raised this case because it nicely illustrated the consequences of T5's jump masking or shadowing (or whatever it's called), and was quite relevant to the discussion. I could equally say that some want to make that work, while others insist on looking for reasons to ignore or dismiss it. I don't really see why I or anyone else should be driven out of a discussion about that subject by people who want to actively dismiss these consequences.

 

[rancke]

If you have jump shadowing, jump masking isn't much of an additional problem. And jump shadowing is inherent in having a jump limit. You can't have the one and not the other. Jump masking has some very interesting ramifications, such as the introduction of travel seasons as star travel will be faster (and thus cheaper) at some times and more expensive at others.

I've been arguing against the claim that jump masking is a huge additional problem, but fusor is right about neither masking nor shadowing being explored by any of the Traveller rules and background material. GT:Free Trader mentions masking, but doesn't provide rules for the ramifications, and GT itself completely ignore them (According to FT, free jumps occur only 5% of the time, yet that's the default situation assumed by the basic GT rules (and, of course, every other version of Traveller)).

If it takes 3 extra days to get from a world to its neighbor then the monthly expenses has to be covered by the revenues from fewer passengers and fewer tons of freight, so the PCs (and the regular lines too) would have to charge more.

If it's cheaper to travel between neighboring stars at some times than at others, more people will travel and more freight will be sent during the cheap times. Free traders will have richer pickings on a particular route during the "season" than off-season, so PCs would have an additional factor to take into account.

(And, of course, price-fixing is right out ).

If Marc Miller wants jump masking to be a part of the Traveller universe, he ought to provide rules that reflect its existence. Indeed, if he wants jump shadowing (which is to say a jump limit) to be a part of it, he ought to provide rules for travel to worlds deep inside a star's jump limit to take longer.


Hans

 

[captainjack]

(And, of course, price-fixing is right out ).

If Marc Miller wants jump masking to be a part of the Traveller universe, he ought to provide rules that reflect its existence. Indeed, if he wants jump shadowing (which is to say a jump limit) to be a part of it, he ought to provide rules for travel to worlds deep inside a star's jump limit to take longer.


Hans

Hans, your premise is partly that we could define this, which I think is fun and always a good idea, but also partly that it should be codified for the rules. I'm going to adress the secon point here, as I think it bears on the whole topic here. Often we fault a game, in this case traveller, because it lacks explicit rules for a situation implied by its background or setting. But, philosophically perhaps, does it need to be ? I'd argue that the structure of traveller as a game is to balance between codification, and intentionally leaving room for the individual GM to make his campaign unique;in short, unresolved questions. Ideally questins that are part of the fabric of the setting (or rules) but that do not break the setting by simply not being resolved. It is also a way to have a GM make a setting his own, and it is also a way to resolve the problem of how one models a universe in less than infinite detail.

For me, its one of those issues that I assume are part of the background unless it matters for a game or an adventure. In other words, I really don't understand the weathers effect on terrestrial commerce, but I'm willing to accept that it exists, and is part of the final cost of eggs. Unless I'm running an egg farming simulation, that is; then, its an element I have to deal with. So (again) for me, this is a matter of balance of effort in a game; things that are common, such as combat, need rules for consistency; things that are essentially a one-off can be resolved once without worry about the next time it will happen. And its seldom either-or; often the more frequently a situation has to be dealt with by a GM defines the need for rules, and their depth of detail.

The issue of masking/shadowing is one of these; clearly it matters a lot for the inhabitants of the OTU, but to what extent does it effect the travellers (the player travellers, I mean). I'd argue that for many campaigns, it is never an issue, and if it is, it is easily (and superficially answered) -as an example -why no effect on shipping prices ? Well, the prices are set by law and tradition, and are averaged out over the entire imperium -like with postage stamps. The same price takes a letter from next door to me to far off Alaska or Hawaii. Economy of scale, plus subsidy blah blah blah. Done, here's your ticket traveller, now please move along. Theres a line.

Yes, masking and shadowing matters to a tramp merchant campaign. But how much ? And how much does the game suffer as a result ? Please note that these are actual questions, not snarky dismissal; and I think important to the issue -I don't know the answers, and that alone, makes the issue quite murky.

So here's what I think is important to the issue: do we have any idea how often jump shadowing/masking is an issue ? The discussion of Spica is clearly an outlier case, and while it provides rich information about spica, does it work at all for exploring a phenomenon that may be of only trivial importance ?

If masking is an unusual issue, then the rule should be simple and general -perhaps somthing like this: on a 2d roll of 11+, modify all prices (for cargo or passage) by +/- 1d6% due to the effects of jump masking (or etheric flux, or alien space bat infestation).
Or one could make it an element of the system generated -define worlds as having hi/lo masking events, give them a constant modifier.
If it is a rare issue, then let the GM deal with it in the one or two times it comes up -or ignore it.

If it's common, I'd suggest that it is already accounted for, and the rules simply don't mention it at the level of detail that play occurs. while it is an important issue here and now (in this thread) and perhaps in some games, it needs to be tossed on the big pile of issues that while important for discussion, don't add significantly to the game*.

Actually, I'd argue that it probably isn't a common issue, simply because the rules largely ignore it; although tautological, remember that this is an imaginary construct we are discussing: one can start at either end of a fictional proposition. But that is very much my TU.

Phew. Thanks for letting me get this off my chest. We can return to the usual, and much more entertaining trollish bickering and wet blanketing, I suppose...


*Me, I think way more attention needs to be paid to the implications on OTU history of empty hex jumps, as opposed to say, stellar type, which never matters in the game I'm running; but then again, neither really does the issue of EHJ's. So, should the game rules reflect such an obscure issue, no matter how much I think it matters, especialy when , even then, it doesn'to: .

 

[captainjack]

Or possibly the capture could be a natural (albeit low-probability) event and the Vilani could have done the terraforming. Or a mysterious, otherwise unknown civilization. If the blackbody radiation really is -90 degrees Celcius, then the Ancients probably didn't put the world in that orbit -- they'd have put it a bit closer to the star, close enough to give it Droyne-compatible temperature.


Hans

So, we have Spica as a rogue that was captured, and then discovered by an unknown race, probably while exploring, and then terraformed, and eventually abandoned. A unique case, surely, but not an impossible one, and not one that need be repeated. And one that reeks of adventure hooks. Main unknown: who did the terraforming and why.

Alternately, a terrestrial world which gets expelled from its system, freezes out, wanders until captured by spica. Possibly not that long ago. It thaws out enough to have an atmosphere, including its original O2 mix, despite being lifeless (now). It can be much closer to the snow line 9and thus the jump limit, also) since it doesn't need to evolve life here, and an O2 world is proably rare enough that it would get settled regardless. Again, a very interesting adventure hook, this time related more to the original natural history of the planet and its potential inhabitants. Granted an ejection plus a capture is quite unlikely, but not impossible, especially since we have no information on rogues or their origin as far as I can tell.

I'm guessing here that without the requirement for evolving life to create the Atmos here at spica, we can move it quite far out to the jump limit. Numbers anyone ?

Hows that work ?

 

[aramis]

Jack, the one problem with Oxygen (and Flourine, for that matter) is reactivity. It reacts with just about anything. Free O2 in an atmosphere is considered proof of life, that's how reactive it is. In order to retain the O2 percentage, for more than a couple years, at least, there would need to be some surviving life. Possibly from deep water that doesn't freeze due to crust-ice insulation coupled with radiothermal decay... and then reevolves photosynthesis when the ice melts...

 

[captainjack]

Jack, the one problem with Oxygen (and Flourine, for that matter) is reactivity. It reacts with just about anything. Free O2 in an atmosphere is considered proof of life, that's how reactive it is. In order to retain the O2 percentage, for more than a couple years, at least, there would need to be some surviving life. Possibly from deep water that doesn't freeze due to crust-ice insulation coupled with radiothermal decay... and then reevolves photosynthesis when the ice melts...

Assuming that the ejection portion of the scenario occurred fairly quickly, would the frozen atmosphere still retain its O2 ?

Also, I'm not sure that your assumption that a non-biotic O2 atmosphere would be lost/ reactively bound as quickly as you suggest; in theory, most of a planets oxygen sinks need to be saturated before an oxygenation event can happen, and that's presumably the case before it was ejected. The question is how long a thawed fossil atmosphere could last or at least at what rate would it deplete. For the scenario to work, it could be a capture as little as a few thousand years.

I'm willing to hear that that's a mistaken assumption, too; anyone got the numbers or refences ?

 

[fusor]

So here's what I think is important to the issue: do we have any idea how often jump shadowing/masking is an issue ?

It is an issue to some extent (between "not much" and "a lot") everywhere now, since it's unambiguous that ships drop out of jump when their path intersects the 100D limit of any object in their way or at their destination.

If a world is a satellite of a gas giant, then it will be dropped out of jump at the gas giant's 100D limit, which is at most (for a jupiter-size planet) about 15 million km (0.1 AU) from the gas giant, which is usually well beyond the orbits of its large satellites. So extra travel time is required there.

For M Dwarf stars, the 100D limit is 0.1-0.35 AU from the star (depending on stellar radius). All planets in those stars' habitable zone are well within that distance, so it adds some extra sublight travel time there (not a lot, but some). Given that these stars are extremely common, this changes things for a lot of systems. For other main sequence stars it shouldn't really be an issue since the stars' 100D limits would be inside their habitable zone, but there's still the chance that the planet is on the wrong side of the star (in the shadow of the star's 100D limit) relative to the system that the ship departed from, which means the ship would be pulled out of jump on the far side of the star..

It could matter in multiple star systems. Presumably each companion star would have its own 100D limit in a close binary, so it makes a 'peanut-shaped' 100D limit around the pair that cannot be jumped through. For near companions it would create an obstacle for certain in-system travel routes (e.g. you wouldn't be able to jump from the primary's inner system to a planet directly behind the companion star, at least until the companion star moves out of the way on its orbit). A Far companion's 100D limit might cause an obstruction to ships coming in from systems along that line of sight, though this would be less probable.

It obviously affects planets around Giant stars the most, since those stars' 100D limits are now very large. Antares' 100D limit is the largest at about 750 AU, but that's a special case since it's a supergiant (Betelgeuse is similar). The 100D of more 'normal' (and more common) red giant stars evolved from sun-like stars (e.g. Pollux, Arcturus) would be between 10-150 AU. Red Giant stars don't have habitable planets though, but they probably have "planets of interest" around them that will mostly be within 50 AU, so this could add significant sublight travel time.

However, it is a complete myth is that this would affect ships travelling through asteroid/comet belts or oort clouds - it won't affect them at all. The 100D limits of asteroids is still absolutely tiny compared to the vast amount of space around them, so the probability of intersecting a 100D limit there is absolutely tiny too. It might be more significant a problem if travelling across a densely packed inner asteroid belt though, but then the star's 100D limit is probably a bigger issue. Ships won't be pulled out of jump by interstellar planets/brown dwarfs/comets for similar reasons - those are tiny compared to the space around them, and the probability of intersecting a 100D limit between stars is astronomically low. Such "pull-outs" would be extremely rare events.

 

[captainjack]

It is an issue to some extent (between "not much" and "a lot") everywhere now, since it's unambiguous that ships drop out of jump when their path intersects the 100D limit of any object in their way or at their destination.

This is great. Numbers are always better.

So my question is, in general, how many hours/days will masking add to a ships transit in a worst case scenario or on average.


I'll use a worst case analysis: the jump point, target star and target planet for a perfect line, and the target is exactly on the opposite side of the the ships entry point .
For the extra distance we will assume that the navigator is competent, and if the destination is exactly on the other side of the star or GG, he will set his exit point so as to minimize the distance; IIRC my geometry, that will be centered on the mass directly above a straight line thru it. So the max additional distance is SQRT( 2(jumplimit^2)). for equal arms, this can be estimated at 1.4* either of the arms.

I'll use 10m/s^2 for 1 G and fudge 1AU as 150 milliion Km

Okay.

The examples are very helpful. If I do a cut an comment,here, it is only to figure a travel time for most cases...not an internet special line-by-line dissection

Using the continuous thrust travel time calculator at http://www.transhuman.talktalk.net/iw/TravTime.htm
and setting the turnover option we get the following additional times.

If a world is a satellite of a gas giant, then it will be dropped out of jump at the gas giant's 100D limit, which is at most (for a jupiter-size planet) about 15 million km (0.1 AU) from the gas giant, which is usually well beyond the orbits of its large satellites. So extra travel time is required there.

~25 hours extra, worst possible alignment.

For M Dwarf stars, the 100D limit is 0.1-0.35 AU from the star (depending on stellar radius). All planets in those stars' habitable zone are well within that distance, so it adds some extra sublight travel time there (not a lot, but some). Given that these stars are extremely common, this changes things for a lot of systems.

37 extra hours, worst possible alignment.

For other main sequence stars it shouldn't really be an issue since the stars' 100D limits would be inside their habitable zone, but there's still the chance that the planet is on the wrong side of the star (in the shadow of the star's 100D limit) relative to the system that the ship departed from, which means the ship would be pulled out of jump on the far side of the star..

Okay, we'll assume a 1AU jump limit which is a star a bit bigger than Sol.

Worst case extra distance is then SQRT(2AU)= 1.4 AU.

81 hours (3 days, 9 hours.), worst possible alignment.

It could matter in multiple star systems. {snip} A Far companion's 100D limit might cause an obstruction to ships coming in from systems along that line of sight, though this would be less probable.

Less of an issue. not only will the worst case alignment be less common with multiple bodies, one can still make a jump to a point near the target above a straight line with the elevation based on the largest Jump limit. In most cases, I'd suspect that it won't be more than (1.4^2 * jump limit ) additional distance. Call it double the jump limit. At the outside, I'd say 5 extra days (etc).

The 100D of more 'normal' red giant stars evolved from sun-like stars (e.g. Pollux, Arcturus) would be between 10-150 AU. Red Giant stars don't have habitable planets though, but they probably have "planets of interest" around them that will mostly be within 50 AU, so this could add significant sublight travel time.

so, worst case, 150 AU limit, travel time is in excess of 90 days from exit to a planet 50 AU out. However, this is always the case, so presumably the stellar charts note that you need to pack extra supplies and fuel.


lets sum up.

Typical travel time and expenses allow for 1 week to jump point, 2 weeks in jump space, and one week in transit from exit.

Unmasked, perfect world Typical time to jump, and time to planetfall from exit can use the 100D limit both ways - which for earth is about 6 hours at 1G (both legs use turnover)For fun, I'm going to assume that jump time is always 2 weeks.

Unmasked, perfect world Typical time to jump, and time to planetfall from exit can use the 100D limit - which for earth is about 6 hours at 1G ; so best possible run between two big earth-types takes 14.5 days .

Generally, if the time is less than a week at either end, that just means that the ship has that much down time before the next trip . Budget and logistics cycle for a typical merchant is for 4 weeks per trip, or 28 days.


Masked gas giant moons, and planets masked by main sequence M-G stars should account for at least 90% of planets assuming that they are randomly distributed amongst the true distribution of star types, right ? overall, masking might add 3 days worst case, or 17.5 days. So, still good, only a little less time for R&R, maintainence, wheeling and dealing. The loss is probably less than the average delay for pratique, customs, red tape, etc.

In fact, one only exceeds the time budget of the 1 week planetfall if the distance from exit is in excess of 7 AU.

When one considers the distribution of giants, I'm guessing a very small proportion (of the remaining 10%) will have a jump limit in excess of 5AU (which under the worst conditions caused 1.4* as much distance to be added.)


One more consideration: all of the above are worst case configurations: the target planet is exactly on the other side of the star (GG) and right at the star's Jump limit. For half of the year, any extra distance is decreasing, and for the other half it is pretty close to zero. I'd argue that such worst case situations are very rare, and could mostly be solved by scheduling.

So what does this mean ?

1. Jump masking is a trivial issue with respect to trade or transit with almost all planets. The extra time involved can almost always be subsumed in the standard operating schedule (which means that, surprise, those rules work, even after 35 years) For the rarest of cases, it can add significantly to the time, but that will always be the case for those destinations, and costs and supplies can and will be calculated accordingly. Now....those weird ones ? Those are where the Travellers go. And it effects them/us. But, that doesn't effect the cost of eggs in a galactic market...until they blow up the ancient machine supporting hyperspace, obviously.

2. The situation at Antares is unique, and can be deconstructed for cause without screwing up or setting precedent everywhere. Maybe it is an ancient project to observe Antares in great comfort; maybe an AMAZING ACCIDENT OF FATE !!!!!

 

[rancke]

Often we fault a game, in this case traveller, because it lacks explicit rules for a situation implied by its background or setting. But, philosophically perhaps, does it need to be ?

Obviously it's possible to ignore it. It's been ignored for over 30 years by writers and referees alike, myself included (Though I did include it as a minor plot point in one adventure I wrote for JTAS Online).

But what does a referee do if he doesn't want to ignore it? He is completely on his own. So is this something that comes up sufficiently often to warrant inclusion in the rules? What if it comes up every other jump? What about 19 jumps in 20?

I'd argue that the structure of traveller as a game is to balance between codification, and intentionally leaving room for the individual GM to make his campaign unique;in short, unresolved questions. Ideally questions that are part of the fabric of the setting (or rules) but that do not break the setting by simply not being resolved. It is also a way to have a GM make a setting his own, and it is also a way to resolve the problem of how one models a universe in less than infinite detail.

What does it mean to break the setting? If the referee has to tell his players "and remember, we're ignoring that it actually takes you an extra day to reach your destination and pretending that you can jump straight to its 100D limit" every other jump, is that broken?

The issue of masking/shadowing is one of these; clearly it matters a lot for the inhabitants of the OTU, but to what extent does it effect the travellers (the player travellers, I mean).

If they seldom travel, it seldom affects them. If its ignored, it never affects them. If it's addressed when it ought to be addressed, about every other time they jump.

I'd argue that for many campaigns, it is never an issue, and if it is, it is easily (and superficially answered) -as an example -why no effect on shipping prices ? Well, the prices are set by law and tradition, and are averaged out over the entire imperium -like with postage stamps.

A jump-2 ship doing a free jump (i.e. one not affected by jump shadowing or jump masking) can survive of the traditional prices. Subtract 10 or 20% of its revenues and it is in deep do-do. One could argue that since the prices already don't work for jump-3 and jump-4 ships, it's no big deal that they won't work for jump-2 either, and that's one way o looking at it, to be sure. But I don't want to ignore jump-3 and jump-4 traffic either; I want the prices to makes sense for everything from jump-1 to jump-6 traffic.

The same price takes a letter from next door to me to far off Alaska or Hawaii. Economy of scale, plus subsidy blah blah blah. Done, here's your ticket traveller, now please move along. Theres a line.

I can assure you that if you were paying only just enough to have someone bring your letter next door, you wouldn't be able to get a letter sent to Alaska.

do we have any idea how often jump shadowing/masking is an issue ? The discussion of Spica is clearly an outlier case, and while it provides rich information about spica, does it work at all for exploring a phenomenon that may be of only trivial importance ?

According to FT, 1 in 20 jumps is a free jump, i.e. affected by neither jump shadowing nor jump masking. Ignoring jump masking, a good guesstimate would be that more than 50% of mainworlds are inside a jump shadow. (See for yourself; grab a subsector listing with star types and count the number of KV and MV stars).

If it's common, I'd suggest that it is already accounted for, and the rules simply don't mention it at the level of detail that play occurs.

The level of detail of the game is hours and even minutes. There are rules for figuring out how long it takes to get from surface to orbit, from orbit to the planetary 10D limit and from the 10D limit to the 100D limit. At which point the rules invariably have you jump instead of having you proceed from the planetary 100D limit to the solar 100D limit, thereby introducing a sizable difference in the time it takes. Now, if the referee want to ignore the extra X hours that last bit of the voyage would introduce, he should certainly be allowed to do that. But I really feel he should also have the option of not ignoring it.

...while it is an important issue here and now (in this thread) and perhaps in some games, it needs to be tossed on the big pile of issues that while important for discussion, don't add significantly to the game*.

Well, I think jump shadowing and jump masking have the potential to add significantly to the game. I've already mentioned adding seasons to star travel. Dan mentioned the tactical advantages of being deep inside a jump shadow. Hearing that the rival expedition just arrived at the solar jump limit and will reach the planet in 36 hours might add spice to a treasure hunt. Other suggestions would probably be variations on the same theme, but I think there's a lot of potential in those variations.


Hans

 

[whartung]

Well, I think jump shadowing and jump masking have the potential to add significantly to the game. I've already mentioned adding seasons to star travel. Dan mentioned the tactical advantages of being deep inside a jump shadow. Hearing that the rival expedition just arrived at the solar jump limit and will reach the planet in 36 hours might add spice to a treasure hunt. Other suggestions would probably be variations on the same theme, but I think there's a lot of potential in those variations.

I think, as a general rule, one can basically consider Jump Masking (i.e. the gravity well that creates the 100D entry/exit limit) is a constant for any particular system, because you simply can't get any closer to the destination. The only exception to this would be if for some reason a destination is in an orbit next to, say, a gas giant, and some parts of the "year" the destination is masked by the giant, and other times not. But for the general case of masking by the destination world itself or the star it orbits, it's pretty much a constant.

Jump Shadowing (i.e. jump is blocked by "line of sight") can be, as you said, seasonal. Simply you can edict that during certain times of the year, you'll have to "go around" in order to make the trip, with "go around" defined as either sublight to the other side of the blocking object (in whichever system) or, even more simply, jumping around it. That is, since system A and B are Shadowed, you have to jump to C first.

The nice thing about the second technique is you can do just craft a simple schedule (every other 3 months, say) that ships just know about, but without having to do a bunch of simulation or math or whatever. Just pick something and stick with the schedule, since there's no surprises in space navigation.

My point is that the masking should be able to be calculated during system generation, and shadowing can be done on a whim and simply noted, without having to go through a bunch of rigorous mechanics.

 

[rancke]

I think, as a general rule, one can basically consider Jump Masking (i.e. the gravity well that creates the 100D entry/exit limit)...

Jump Shadowing (i.e. jump is blocked by "line of sight")...

Other way around. Jump shadowing is when the destination is inside a jump limit (aka jump shadow). Jump masking is when the destination is behind a jump shadow. It may well be outside the shadow, but it is "masked" by it.

As for your arguments, I entirely agree. I'm not proposing to introduce some highly complicated rules to deal with these matters, merely to deal with them somehow. Most rules simplify highly complex situations, so why not the rules dealing with this?


Hans

 

[fusor]

Other way around. Jump shadowing is when the destination is inside a jump limit (aka jump shadow). Jump masking is when the destination is behind a jump shadow. It may well be outside the shadow, but it is "masked" by it.

That may be how they've been defined, but if so then I think that's the wrong way around, which is why that explanation doesn't really make much sense.

Masks go on top of stuff (e.g. a mask is on top of a face). Shadows are behind stuff (e.g. a shadow is cast behind you when you stand next to a light).

So, to be consistent with the definitions of the words, "jump masking" should be when you are within (covered by) the 100D limit, and "jump shadowing" should be when you're behind (in the shadow of) the 100D limit.

 

[rancke]

That may be how they've been defined, but if so then I think that's the wrong way around, which is why that explanation doesn't really make much sense.

That is how I and most people I know use them and the comments weren't explanations, they were mnemonic tags.

It's also how they've been used throughout this discussion, so in the interest of avoiding confusion, I think it would be best to stick to that.


Hans

 

[atpollard]

That may be how they've been defined, but if so then I think that's the wrong way around, which is why that explanation doesn't really make much sense.

Masks go on top of stuff (e.g. a mask is on top of a face). Shadows are behind stuff (e.g. a shadow is cast behind you when you stand next to a light).

So, to be consistent with the definitions of the words, "jump masking" should be when you are within (covered by) the 100D limit, and "jump shadowing" should be when you're behind (in the shadow of) the 100D limit.

Just to view the words differently ...

If I stand in a shadow, you can still see me and hit me in the face with a boston cream pie ... like the 100 diameter jump shadow that covers the destination world, but will still allow you to get there on MD eventually.

If a hedge between you and me completely masks your view, then you cannot hit me in the face with a boston cream pie ... like the Jump Mask of a star system directly between your initial position and the target world.

A shadow just slows you down while a mask completely stops you.

[As for me and my Traveller, we Shadow but do not Mask ... what business does an alternate universe have being yolked to the normal universe except at the points where they converge - the start and end of a jump!]