I've never gotten that. And, T5 shows how vector can be altered while in jump so that exit vector is different from entry vector.
I'm interested in the OTU version.
As far as I know, CT just says you exit realspace at A and appear a week later at B, with the caveat that you have to get out past 100 diameters to avoid a penalty, and with the assumption that you will exit at the destination "jump point", i.e. 100 diameters out. To the best of my knowledge, it is not specifically stated whether or not you can push that to exit jumpspace closer to the planet on arrival - say, to avoid a possible encounter or to reduce your exposure time in case one occurs (very useful if you're a smuggler trying to reach a red-zoned planet patrolled by the Navy). It's just presumed you exit at the "jump point," and one likewise presumes the gamemaster would shoot down any proposal to try to exit closer to prevent the Navy blockades from being pointless. However, I don't see an emphatic, "Thou can'st not," in CT. Nor is there any specific statement that you can or cannot tell where someone else goes. In point of fact, I don't even see anything specifically insisting on conservation of momentum.
Then Mr. Miller in a JTAS article (JTAS 24) gave it more detail: conservation of mass and energy applies*, and you could not exit jumpspace within 100 diameters - you'd precipitate out naturally when you reached that point of your destination. An implication of that last is that jump is directional, i.e. there is a 1:1 correspondence between points in normal space and points in jump space such that when you reach the point in jump space equivalent to the 100-diameter sphere surrounding a world, you naturally drop out of jump space. Were it otherwise, you could hypothetically exit jump space on the other side of the planet or miss the planet altogether and keep going, but the language was that you precipitate out when you reach that point.
A logical extension of that rule was that you'd precipitate out upon intersecting other gravity wells also. Ergo, you could not reach the 100-diameter limit of a planet or star and then point yourself back at the planet/star to jump to a system on the other side of it. That set logical limits on what you could reach: anything on the "blind" side of the planet or the system's star could not be the destination.
A second point was, if you had a drive capable of more than Jump-1, it took more energy and fuel to achieve the higher jump. A ship monitoring yours could read your energy output and figure out how far you were jumping based on your energy output. Knowing that, and knowing where you couldn't go based on the jump shadow of the planet and/or star you were departing, one could make an educated guess at what targets remained.
However, an educated guess is not certain knowledge. The article
doesn't say that striking a 100 diameter limit is a requirement for exiting jumpspace: he may infer what system you're headed for, but if you've planned to exit jump space at some planet other than the primary world in the system, or at some random point in space in the system instead of at a world, then you're a very small needle in a very large haystack, and knowing which haystack does him little good.
Further, the view that you can infer a destination from available data, but not specifically know the destination, is supported by a statement in the section on micro-jumping: "
Because a ship's jump destination cannot be predicted, a microjump within a system still leaves an impression that the ship has left; a week later, it emerges from jump in the same system, to the observer's confusion."
*This meant, among other things, if you tossed something out the airlock, it would precipitate out into normal space, possibly right along with you or possibly at some point in interstellar space, or at least it's equivalent in mass/energy would - jump space physics have lots of fun with objects not within the jumping ship's jump field, and an object spread as individual atoms or energy across a light-minute or so of space would certainly obey that conservation rule.
Got a page number for Annic Nova? I'd like to read what it says.
I see nothing in either the double-adventure or the JTAS adventure that implies an ability to track the ship's jump.
