[TML] Jump variation

[Jerry W Barrington]

I was reading http://www.freelancetraveller.com/features/rules/jumpimpl.html
today, and had a thought.  Over very long range, it is difficult to use
active sensors, so detecting jump signatures would likely use passive.  This
should make it hard to get timely, accurate measure of distance and of ship
size.  Combining this with the variation in jump exit distance, the Jump
Signature referred to on that page should not be rated simply in
dTon*parsecs.  It should also account for the possible distance of the
jumping vessel from the sensor.  This adds a degree of freedom to the
interpretation of the signature.  This is why the signature *should* be
measured in watts or joules, adjusted by actual distance sensed.  This
leaves more for the operator to estimate/interpret, leading to possible
error or ambiguity.

For that matter, to be able to make the measures implied on that page,
either highly sensitive measure must be constantly made of the whole sky
(impractical), or the signature has to be generated over a long period of
time.  But every canon mention I've seen of a Jump flash implies that it is
pretty well instantaneous.  That isn't good for getting a measure of it.

For that matter, just how variable is the exit point?  The only reference I
can find is JTAS 24, pg 34-35: accurate to 1 in 10 billion, or about 3000 km
per parsec jumped (I calculate it to 3086km).  On a Jump 6, that could be a
few diameters!  Anything more canonical?