Sorry for the delay. Prologue that I gave to my players. Its a bit rough, but sets the scene.
 
+++ Intercepted On - 3.506850.M41 +++  
+++ Intercepted Communications Between PDF Tayven and Imperial Fleet Gothos +++  
+++ Encoded Distress Signal - Origin Tayven, Sector 7G, Jericho Reach +++  
 
This is the Planetary Defense Force for the Imperial world Tayven calling Imperial Fleet Gothos. A ship of unknown origins has appear in local space and decimated our defenses. By the Emperor's Light, if it wasn't for the noble sacrifice of the Belsarius, we would have been overrun.  
 
The enemy ship is disabled, though our own forces have been destroyed. We formally request that you aid us in the destruction of this vessel before their crew can repair it and launch a ground attack on Tayven.  
 
Please find encoded a transcript of the attack, it may assist you.  
 
May the blessing of the Emperor be on you, and speed your journey to Tayven.  
 
-----  
 
+++ Audio Logs - Tayven Planetary Defense Forces Headquarters - 3.503850.M41 +++  
"…Did you her what happened to Fergus? That was uncalled for. Emperor knows he can be forward, but he didn't deserve that."  
"What did he expect, that's a guardsmen bar, and have you ever seen an unarmed guardsman? They'd die before they surrender their rifle. When's the funer…."  
 
*Alarm sounds in background*  
 
"What in the name of Holy Terra is that? Have you seen anything like that before?"  
"Look at it! It must be 20km long! Warping in to high orbit, what kind of a lunatic would do that?"  
 
[Belsarius - Defense Fleet]  
"This is Admiral Gorge of the Tayven Defense Fleet to unidentified vessel. You have entered Imperial space. Stand down and identify yourself"  
 
[unknown Vessel]  
"Dis is Warboss 'Edscratcha, of dah vesshel, vesshel…. Bah! We's don't need no fancy names. We's gonna let our guns do dah talkin'. Oi, Bratz! Release dah DAKKA!"  
 
[Belsarius]  
"Ork scum! All Ships! Move to engage! Make the Emperor proud!"  
 
[HQ]  
"Defense fleet is moving to engage. Ork vessel is accelerating towards them. Ships will be within weapons range in two minutes."  
"Preparing ground based defenses. Do we have any more information on that ship?"  
"Not yet. Initial scans show that it has been in space for a long time. A long, long time. Wait, something's happening. How far out is the defense fleet?"  
"About 60 seconds now."  
"It looks like the Ork vessel is about to fire. They can't do that, Ork weaponry doesn't have that kind of range. What is that ship?"  
 
[Ork Vessel]  
"Humies! We's got a new gun. We's ain't sure what it does, so's we's gunna test it on yous!"  
*Various cheers, whoops, shouts, and gunshots in the background. Mostly incomprehensible.*  
 
[Merciful Truth - Defense Fleet]  
"A thousand thrones to the first officer to attack that ship!"  
"Sir! Enemy vessel has locked on! There's a large energy build-up coming from the Ork vessel - off the scale. I've never seen anything…"  
"Gunner Officer, keep talking like that and I will have you taken away for treason. We have the Emperor on our side! We will be victo-"  
 
+++ Communication with Merciful Truth lost+++  
 
[HQ]  
"One hit, just one shot… That was a cruiser. What chance do we have?"  
*Sound of an impact*  
"Pull yourself together! Organise the ground defenses! Send an alert to all guardsmen, we may have need of them soon."  
"You hit me! You didn't have to hit me! Alerting the Imperial Guard now."  
 
+++ Communication with Dying Light lost +++  
+++ Communication with The Iron Banner lost +++  
+++ Communication with Dauntless lost +++  
+++ Communication with Ascendant Dawn lost +++  
 
[Belsarius]  
"All decks prepare for ramming speed! We need to end this now or there will be nothing between us an Tayven. We are the Emperor's will made manifest! We are the defenders of humanity! We will not be defeated by Orks. Though we may die this day, the Imperium shall survive!"  
"It has been an honour to service with you, Admiral."  
"And you, Captain."  
 
+++ Communication with Belsarius lost +++  
 
[HQ]  
"The Belsarius is gone, but it looks like they have disabled the Ork ship. Its engines are offline, and half its weapons systems are destroyed. If the Orks salvaged that ship once, then its only a matter of time before they can get it running again."  
"Orks will find a way! They always do! Its only a matter of time! Can't you see that? I've seen the vids of what they do to worlds, of what they do to enemies, prisoners, even themselves! We need to run, if we go now we can still make it to a sh-"  
 
*Sounds of a laspistol being fired twice. Noise of a body hitting the floor*  
 
"You talk too much. We have a duty to our world, and we must follow it. Planetary Defense log, official report: unidentified ship appeared in orbit and destroyed the majority of the defense fleet with unknown Xenos weaponry. The final actions of the Belsarius crippled the ship at the cost of itself and its crew. Our orbital defense are effectively zero, and enemy ship is intact, if inactive. It is unknown how long it will take the crew to repair that vessel. I am requesting support from the nearest Imperial Fleet, Striker. At maximum speed they could be here in two weeks. Sending distress signal now."  
 
+++ Audio Transcription Ends +++  
 
+++ Signal Ends +++  
 
 

I had a whole post written out, and then closed the window... Not my best move.
 
Ok, disclaimer: this is my first time running Deathwatch, I have run several successful campaigns in other systems including Black Crusade and Warhammer FRPG 3rd ed (cards and everything!). Personally I prefer running low-power games, but I thought it'd be fun to run a high-power game for a change.
 
Characters:
 
Julius - Ultramarine Tactical Marine
Veteran of an Ork invasion, he was critically injured in the last days of the attack. An Ork stikkbomb destroyed his armour, scarred his face, and cost him an ear. In the weeks that followed, his squad were ordered off-world. Given the critical state Julius was in, they left him behind. Abandoned, Julius took it upon himself to rebuild his armour using whatever pieces were spare, and then headed to a Deathwatch watchtower to enlist.
 
Astelan - Dark Angel Techmarine
Astelan has a passion for ancient, lost, and retricted lore. He will do anything if it leads to more forbidden knowledge. He first met Naaman when he was working on gunship maintenence. Naaman was assigned to one of the Thunderhawks as a gunner, and they swiftly became allies. With Naaman's expert training, Astelan was not only able to accept a Space Wolf's challenge to a duel, but win it outright.
When Astelan requested to join the Deathwatch, mainly to have access to information otherwise denied to him, he asked Naaman to join him.
 
Naaman - Dark Angels Assault Marine
Naaman is always willing to strike first and ask questions later. His time spent as a gunner on a Thunderhawk gunship gave him his love for flying, and raining down death from heaven above. Adventure drives Naaman, so when Astelan asked him to join the Deathwatch together he accepted without hesitation.
 
Alonius - Blood Ravens Librarian
Alonius is the hardest to write up at this time for two reasons - First, I am not that familiar with the Blood Ravens. I need to read up on them. Second, the player has missed two of four sessions so far.
I believe his motives are similar to Astelan's, and his own Chapter's natural inquisitiveness to find out more about their Chapter and primarch.
Alonius was part of the 5th Company, which vanished for many years before returning. No-one, not even Alonius knows where they went. There is a hunger within him to find out what was taken from him, and why.
 
Bareal - Blood Angels Apothecary (NPC)
Bareal is a grumpy 6-700 year old Space marine veteran. His bedside manner is non-existant. His duty in this group is to oversee their first few Deathwatch missions, offer support, and crucially, not let them die. Failing that, Bareal is there to ensure that their geneseed is recovered and can be reused.
As Bareal could outshine the Players, or take control of the group, I tend to keep him in the background as much as possible. He is an observer.
 
*Edit - I think that's everything.

I had a whole post written out, and then closed the window... Not my best move.
 
Ok, disclaimer: this is my first time running Deathwatch, I have run several successful campaigns in other systems including Black Crusade and Warhammer FRPG 3rd ed (cards and everything!). Personally I prefer running low-power games, but I thought it'd be fun to run a high-power game for a change.
 
Characters:
 
Julius - Ultramarine Tactical Marine
Veteran of an Ork invasion, he was critically injured in the last days of the attack. An Ork stikkbomb destroyed his armour, scarred his face, and cost him an ear. In the weeks that followed, his squad were ordered off-world. Given the critical state Julius was in, they left him behind. Abandoned, Julius took it upon himself to rebuild his armour using whatever pieces were spare, and then headed to a Deathwatch watchtower to enlist.
 
Astelan - Dark Angel Techmarine
Astelan has a passion for ancient, lost, and retricted lore. He will do anything if it leads to more forbidden knowledge. He first met Naaman when he was working on gunship maintenence. Naaman was assigned to one of the Thunderhawks as a gunner, and they swiftly became allies. With Naaman's expert training, Astelan was not only able to accept a Space Wolf's challenge to a duel, but win it outright.
When Astelan requested to join the Deathwatch, mainly to have access to information otherwise denied to him, he asked Naaman to join him.
 
Naaman - Dark Angels Assault Marine
Naaman is always willing to strike first and ask questions later. His time spent as a gunner on a Thunderhawk gunship gave him his love for flying, and raining down death from heaven above. Adventure drives Naaman, so when Astelan asked him to join the Deathwatch together he accepted without hesitation.
 
Alonius - Blood Ravens Librarian
Alonius is the hardest to write up at this time for two reasons - First, I am not that familiar with the Blood Ravens. I need to read up on them. Second, the player has missed two of four sessions so far.
I believe his motives are similar to Astelan's, and his own Chapter's natural inquisitiveness to find out more about their Chapter and primarch.
Alonius was part of the 5th Company, which vanished for many years before returning. No-one, not even Alonius knows where they went. There is a hunger within him to find out what was taken from him, and why.
 
Bareal - Blood Angels Apothecary (NPC)
Bareal is a grumpy 6-700 year old Space marine veteran. His bedside manner is non-existant. His duty in this group is to oversee their first few Deathwatch missions, offer support, and crucially, not let them die. Failing that, Bareal is there to ensure that their geneseed is recovered and can be reused.
As Bareal could outshine the Players, or take control of the group, I tend to keep him in the background as much as possible. He is an observer.
 
*Edit - I think that's everything.

Interrupts and actions are completely separate things and you'll need to bone up on them in the RRG as they're a key part of the game. And the battle flowcharts pg 22.
 
An action can be done in any action window. There's an action window before and after every combat turn. Both players can do actions in any given action window, regardless of whose turn it is to do the next attack and who has initiative.
 
In your example, you can do your action in the action window BEFORE the opponent starts his combat turn. But once he's started his combat turn (ie declared his attacker), no further actions can be taken until the combat turn is fully resolved. Then, another action window opens.
 
Unless he only has one ready unit left, you won't know who his next attacker will be when the action window is open.

Ok, since we all know the hub, then why don't we go next Monday(the 19th) and see who's about?