Spoiler: the focal point is 3.5x the distance to Voyager 1.
if to use existing nuclear reactor tech and already existing, as tested by NASA (and drives Starlink satellites), ionic drive - about 3500 ISP - that focal point would take about 10 years to reach. I hope that SpaceX flights to Mars will, after the probably first chemical ones, be done using ionic drive with solar as it is just faster, thus getting tech developed and with adding nuclear for beyond Mars - so in 10-20 years we'll have the stuff flying. (note that "small" reactors - 100MW - we have for submarines, and with MS, ORCL, GOOG, AMZN getting into nuclear we'll have such small reactors productized into normal commercial use which will simplify space use too as commercial use require higher reliability/etc. compare to military)
> that focal point would take about 10 years to reachIs this taking into account the time needed to slow down?
It is the napkin scale, not precise mission calculation. Doing 2 stages you can get faster, doing higher voltage you can get faster, etc. Slow down would of course take time and delta-v, changing observation station would also take them, etc. What interesting is that increasing Isp 10x seems to be doable with the today's/near-future tech, and that would even allow 1000 year mission to the closest star using 3 stages (unfortunately even my napkin breaks though when trying to stretch to the 100 years mission to the star using the today's/near-future tech).
Right, but assuming constant acceleration, there's an enormous difference between accelerating all the way to the target and only accelerating halfway to the target, and then decelerating the rest of the way.
Silly question. Can you do a "drive by". In other words not slow down. How much time you need to "take the photo". I am using terms like Randall in Thing Explainer here!!
Maybe it has further missions in deep space after that. Or look in other directions and use other stars.