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I dont believe anyone has estimated AT_AT firepower, from the battle of Hoth there is an opportunity to estimate the "maximum firepower" using:
heat content = (Pi/6)*(d^3)*P/0.4 (SWTC, explosions section)

Firstly we need to know the height of the cockpit viewport. From the film we can see it is at least as tall as the modified stormtrooper helmet worn by the crew. The original stormtrooper helmet is 35cm x 35cm x 48cm. i.e~35cm.
We can also estimate the viewport height directly from the battle scene. If a walker is 23m tall, the ‘head’ is ~4.5m; therefore from the macrobinocular image the viewport is < 40cm. From Luke’s strafing run the head appears to be ~4.2m (again using 23m overall height). And from ICS the head appears to be 4.2m putting the viewport at 35cm. In short it is 35cm in height.

Secondly using the ICS/TJ diagrams we can obtain the maximum distance from the viewport. It cannot be greater than ~1m in the following shot, given the position of the Driver/gunner relative to the camera (and that it is in front of General Veers station).



We can now estimate that the generator subtends >0.1 radians (generator 55 pixels, viewport 165 pixels high). If the distance is 17.28 Km, the generator is >1.7Km across. However this shot takes place at 28:54, General Veers walker reaches 17.28 Km at 31:34. Assuming the walkers made steady 5m/s progress (guestimate based upon walker taking ~2 seconds to half enter a shot) with no time cuts (208 s) the generator is at 18.32 Km thus >1.8 Km across. This now gives us a rough idea of the diameter of the explosion in the images that follow.





In image02 the generator is still intact and therefore the fireball is solely from the energy content of two bolts. As this is ~1Km in diameter, this requires ~16 KT per bolt. This is however only the inital stage (note the blinding flash that immediatly follows it), the fireball expands further:





In images 5-7, the fireball expands to its maximum of ~2Km (Image 7) before shrinking to reveal the generator is still there (image 8 ). This is followed by the second larger explosion (Image 10), possibly the generator 'cooking' off?. In any case, as the generator is still there and a secondary explosion occurs, it suggests the 2Km fireball was probably caused by the bolts themselves, thus maximum firepower is ~130 KT per bolt





The second larger explosion is captured in image 10 above, the fireball must subtend a minimum angle of 0.35 radians (constrained by the cockpit layout, fireball 191 pixels, viewport 104 pixels) and thus at 17.28 Km is ~6Km i.e an explosion 6.8 MT. It is not clear weather or not this is due to the generator cooking off or the result of the AT-AT shots.If it is the generator cooking off why the relatively small explosion? after all this generator was capable of holding off any bombardment from the entire Death Squadron.

To summarise:
A "Maximum a firepower" AT-AT shot appears to be 16KT per bolt taking into account only the first stage of the explosion, 130 KT per bolt considering the maximum fireball diameter, and possibly as high as 3.4 MT per bolt if the final fireball was not the result of the generator 'cooking off'.


If any of the images crap-out (they all worked fine in the preview) try viewing them from the index here:
http://man1ac0.tripod.com/index.html

Note that the whole explosion takes place over 52 frames before the scene change to Veers Walker. A seven second DivX clip (5.02 codec required, 874kb) I made and captured the images from is here (right click, save as):
http://man1ac0.tripod.com/GenExplosionI.avi



Image Links all fixed-Bean

I see that those images are hosted by Tripod.

too lazy to do the math but your figures dont look blatently wrong from a quick skim....

Here's a tip: Go to file manager, select the images, click "rename." Now, rename to .txt files. They'll still be images, but can be linked.

Wow, even 16 KT seems extremely high. But given that it's a bolt, and not a bomb, I guess that makes more sense. Anyone double check these yet, or nitpick at them?

And incidently, if you copy the whole thing and paste it in MS word, the pics become visable.

Remember that the Slave 1 guns are 2 kt and rapid-fire. Also remember this is a glorified APC.

Which if they're causing a fireball consistant with a multi-kiloton nuke why didn't they fire a couple of those into the rebel lines?

Lasers aren't bombs.

The beams interact and transfer their energy into the exotic metal structure of the generator, vaporizing its structure.

Shoot those at the ice and drill km long tunnels meters in diameter down into the ice. The damaging affect on the terrian and make areas impassable for AT-ATs, when their purpose is to neutralize the shield, then drop off troops as soon as possible. Why make their approach more difficult when the lower intensity shots work fine while giving them faster fire rate and not fucking up the land they have to walk across.

Grand Admiral Thrawn wrote:Here's a tip: Go to file manager, select the images, click "rename." Now, rename to .txt files. They'll still be images, but can be linked.

I've done that but presumably the links in my first post need changing now?

I dont get it, they were all there when I previewed it, all there when I checked it after posting

can one of the mod's change .JPG to .txt in my post? or should I just post the whole lot again?

Evil S'tan wrote:I dont get it, they were all there when I previewed it, all there when I checked it after posting

Thats your browser cache messing with your mind.

I think the explosion was the generator blowing up not the laser bolt.
It doesn't make sense that full power shots would be 130kt when the normal shots couldn't have been much more than a gigajoule judging by various ground impacts. If the AT lasers were really so powerful they could of wiped out the trench line in one shot.

Hey genius, turbolaser shot NOT = atomic bomb.

Yet we're using a fireball of a supposedly nuclear scale to try and give them a power rating.

Galaxy wrote:I think the explosion was the generator blowing up not the laser bolt.
It doesn't make sense that full power shots would be 130kt when the normal shots couldn't have been much more than a gigajoule judging by various ground impacts. If the AT lasers were really so powerful they could of wiped out the trench line in one shot.

I've already addressed that (I take it you've accepted the inital 16 KT detonation), the generator is still there after the fireball subsides, this is then followed by a much larger (6Km) explosion.

SylasGaunt wrote:Yet we're using a fireball of a supposedly nuclear scale to try and give them a power rating.

What's the problem? A high density energy bolt strikes a target what happens?:
vaporisation and transfer of heat energy to the surroundings. End result? a fireball.

Someone post this in the Mechwarrior vs AT-AT thread at SB.

Stan, the only thing I can find potentially wrong here is that if this is Veer's Walker, it might be one of the AT-HEs mentioned in AOTC ICS, and thus the size, and scaling could be skewed.

Evil S'tan wrote:

SylasGaunt wrote:Yet we're using a fireball of a supposedly nuclear scale to try and give them a power rating.

What's the problem? A high density energy bolt strikes a target what happens?:
vaporisation and transfer of heat energy to the surroundings. End result? a fireball.

Good now remind me why they didn't fire one of those into the Echo Base defenses and wipe them out?

Why should he have to? We've seen the ability already.

SylasGaunt wrote:Good now remind me why they didn't fire one of those into the Echo Base defenses and wipe them out?

Explain what this line of questioning is supposed to prove. Are you trying to prove that the guns were weak? Too bad you can't explain the size of the initial blast, then.

Are you trying to prove that they were being stupid? The front-line was a minor nuisance to them; why waste max-firepower blasts (for which you don't know the recharge time) on units that are not a threat?

Suppose the use of this blast drains their weapons for a while? Wouldn't it be stupid to use it on anything other than the primary target, particularly when you're being harassed by local air support?

You are trying to generate doubt by pointing out what you see as inconsistencies, but these inconsistencies are hardly of the "scientific impossibility" magnitude, and you fail to provide a consistent alternate hypothesis.

Hey Evil S'tan, could you do some work on these pictures? Or you could check them out on your own copy of TESB:

SylasGaunt wrote:

Evil S'tan wrote:

SylasGaunt wrote:Yet we're using a fireball of a supposedly nuclear scale to try and give them a power rating.

What's the problem? A high density energy bolt strikes a target what happens?:
vaporisation and transfer of heat energy to the surroundings. End result? a fireball.

Good now remind me why they didn't fire one of those into the Echo Base defenses and wipe them out?

Battle field tactics. You don't use massive firepower to clear infantry. You use infantry or smaller rapid fire weapons for infantry. You sacrifice power for flexibility and high volume's of fire. IIRC the ATAT's low power shots were doing just fine against the infantry and artillery positions without the need to bring in the "Big Guns".

I was watching ESB about a week ago, and saw something (at least I think I saw something) that I never saw before. Durring the Hoth battle that we are disscussing, a couple of minutes before the retreat, they showed the rebel positions and in the background were a couple of figures running.

Now I would dissmiss it as rebels running but they were running toward the position. I rewound the tape and watched again, and it appeared that the troops in question were shooting at the position. Is this supporting infantry? Has anyone noticed this too?

Galaxy wrote:I think the explosion was the generator blowing up not the laser bolt.
It doesn't make sense that full power shots would be 130kt when the normal shots couldn't have been much more than a gigajoule judging by various ground impacts. If the AT lasers were really so powerful they could of wiped out the trench line in one shot.

There is a reason why artillery normally uses a bunch of 155mm airbursts or DPICM shells against exposed infantry rather then firing one shell from a 280mm nuclear artillery piece or a 600mm mortar.

Galaxy wrote:I think the explosion was the generator blowing up not the laser bolt.
It doesn't make sense that full power shots would be 130kt when the normal shots couldn't have been much more than a gigajoule judging by various ground impacts. If the AT lasers were really so powerful they could of wiped out the trench line in one shot.

In TPM, we see bolts bouncing off the ground in between the Gungans and Trade Federation ground forces. It seems probable that most shields (planetary and non) interact or "ground" themselves, at at least some of the shielding effect protects the ground.