Looks like what's actually happened in the Coalsack is that the centre of the NHSS shell has moved 20 ly from Musca Dark Region CQ-Y d86 to Musca Dark Region PJ-P b6-1, and the radius has changed from 50[1] to 60LY.
This is rare - first time I've seen an NHSS centre move significantly. Often the NHSS shells change radius (especially around the Pleiades), but I've only seen the centre refined to neighbouring systems[2] as we get more data. Never seen such a big jump in locations so I'm actually dubious that it is 'real' [3].
There doesn't seem to be any obvious reason for this - it would have been nice if they were heading to the bubble, but it doesn't look like that to me
(I checked the other shells and they seemed unchanged this week.)
[1] Actually there was one system just over 50 - but less than 50.1ly, so I spent time investigating the size last week as mostly the shell radii are multiples of 5LY
[2] e.g. the Pleiades shell right now is centred better on Maia (65Ly) than on Merope (67Ly), despite the significance of Merope 5c to the Thargoids
[3] I have visited 20+ systems at ~58 Ly from the new centre - all had NHSS. And I did the same at ~62LY. No NHSS. A similar thing was done last week with the old centre & limits. It's usually obvious when you have the wrong centre as you will only see NHSS in some of the systems.
edit: And Musca Dark Region PJ-P b6-1 was measured as the centre before now, so maybe last week's checks were wrong

Damn I need a better way of tracking this
