Remember that I always go by IC time. For the purpose of this discussion we'll assume that these ships were ready to jump the instant the call was received, no preparations necessary.
I'm assuming this galaxy is the same diameter as our galaxy, 100,000 light years (this is pretty small, I've heard that the space the Empire alone covered was 120,000ly in diameter), and the distance from Honoghr is an 10th of the galaxy (rough measurement I performed with my thumb and forefinger). We're talking about a very low number of 10,000 light years.
Here's a quote from Dark Force Rising on hyperdrive speed:
At 127 light-years an hour it will take you 3.2 days to get here. Now obviously this is a game, and we stretch the rules, the map's accuracy as questionable for plotting time & distance, yadda yadda, so I'm cool with some stretching (if you were something like 4 or 5 hours away by the map I would be fine with you arriving in four or five posts), but compressing 3.2 days into a few hours...
In light of this canon evidence, I'll let you decide how much time it takes your troops to arrive.
Jan, the idea behind Planetary defense systems is that no "side" of a planet remains defenseless. Under the old system, with a single cannon, people would just appear on the side of the planet the cannon was not facing.
The new rule eliminated that. However, it was not meant for you to suddenly have more than one cannon on one side of a planet.
Assuming that the planet has a 24 hour revolution, for the planet to turn a quarter for the next cannon within your system to fire (assuming the warships did not move/drift with the rotation of the planet) would be 6 hours.
You might bring that time down that if you don't want to wait for the cannon to be fully centered to fire to say, two and half hours (a stretch).
So you time jumped 2.5 hours to fire your cannon. If you wish your post to stand, I will simply say that I've secured Mon Calamari (in the 2.5 hours you jumped).
1.The time it takes for a world to revolve is different for most planets(they aren't all the same). However, since I don't know the time, I will use the 24 hour rotation, and will edit accordingly, though this will mean Kraken will need to edit, since his fighters wouldn't see the ion cannon yet.