What are current calcs for the 40k weapons

[IvanTih]

Just curious is Nova Cannon stil 21 petatons or do the Imperial ships do triple digit teraton to single digit petaton?

[Darth Hoth]

From my own, admittedly somewhat limited, understanding, firepower is basically all over the place in the various books (due to Games Workshop not having much of a canon/continuity policy). On the low end there are such sources as the Imperial Guard codex (not quite sure which edition it was; fourth or fifth, probably) that (if I recall correctly) said that a fleet of warships can destroy a city in a matter of hours. Then, on the high end, there is a book in the Ciaphas Cain novel series, Caves of Ice), in which the eponymous character thinks (supposedly, I have not read that one myself) that a flotilla can destroy a continent in a few barrages. So, it can go all the way from kilotons or even less and up to multiteratons or petatons.

[Chris OFarrell]

Its seriously all over the place.

But 21 PERAtons sounds absurdly over the top for a Nova cannon...

[Ford Prefect]

But 21 PERAtons sounds absurdly over the top for a Nova cannon...

A nova cannon is essentially stated to fire extremely large projectiles at essentially .99c. However, I'm not sure we should take 'extremely large' to mean '80 000 tons'.

[Raxmei]

It's an area effect weapon in space. Only a small amount of that's actually going to hit anything.

[Chris OFarrell]

But 21 PERAtons sounds absurdly over the top for a Nova cannon...

A nova cannon is essentially stated to fire extremely large projectiles at essentially .99c. However, I'm not sure we should take 'extremely large' to mean '80 000 tons'.

From what I remember, a chain gang of 'workers' on an Imperial ship was employed to manually pull the Nova cannon shells into the guns, which would strongly suggest it doesn't mass THAT much. Granted some ships will probably have automatic loaders rather then using expendable press gangs, but the weapon itself is the same in terms of the firepower it puts out.

[Ford Prefect]

From what I remember, a chain gang of 'workers' on an Imperial ship was employed to manually pull the Nova cannon shells into the guns, which would strongly suggest it doesn't mass THAT much.

Big deal? Ratings shift around all sorts of stuff in Execution Hour which would logically be far too massive for this sort of practice. Dudes pulling on chains is just an aesthetic conceit of the universe.

[Sea Skimmer]

Its worth considering that the Nike surface to missile system was designed so just three men pushed the 16,000lb missile and booster stack along rails from the elevator to the launch position. No power assist, and no ropes. They just lined up and pushed. You can move some damn big loads with manpower if the load is very well balanced. 80,000 tons isn’t too plausible though because the inertia would be very hard to control. Magnetic bearings or even just turning off gravity could make weight a lot less relevant.

[IvanTih]

Here's a quote from Cadian Blood about it.Now it fires black holes and kills hundreds of loaders.

Cadian Blood Pg 212
: The principles of nova cannon technology are relatively simple.

Generators mounted in Depth of Fury’s prow and the cannon itself charged up, creating a series of powerful magnetic fields. Teams of slaves in the prow work with great loading machinery to feed a specially prepared projectile – an implosion charge the size of a small building – into a great hallway known as the release chamber.

Bulkheads slam down as the nova cannon readies to fire. The firing mechanisms must be isolated from the rest of the ship, and it is rare that all slaves escape in time. As Depth of Fury thundered towards the Terminus Est, battered by the anger of a dozen lesser vessels, Straden demanded haste above all else. Hundreds of slaves and servitors were killed in the preparation even before the ship’s destruction several minutes later.

Upon the order to fire, the magnetic fields accelerate the payload and hurl it from the fixed cannon at something approaching the speed of light. Then the time-consuming and dangerous reloading process takes place, and the cycle repeats.

The payload hurtles through space faster than the human eye (and indeed, most instruments of human design) can track. It is programmed not to implode within safe distance of the firing vessel; a nova cannon’s destructive force is immense.

This failsafe can, of course, be overridden. In only a handful of minutes, it would be.

The projectile lanced across the distance between the two converging ships faster than the blink of an eye. Once it struck, it was programmed to implode, collapsing in on itself and achieving a density so intense that all nearby matter would be sucked inside it and compressed to practically nothingness.

This is how stars die.

And this is what hit the oncoming prow of the Terminus Est.

******

A sizeable chunk of the diseased ship simply ceased to exist, wrenched out of physicality and into nothingness. Consoles chattered and servitors grunted as Depth of Fury’s bridge instruments registered the damage.”

From what I remember, a chain gang of 'workers' on an Imperial ship was employed to manually pull the Nova cannon shells into the guns, which would strongly suggest it doesn't mass THAT much.

Big deal? Ratings shift around all sorts of stuff in Execution Hour which would logically be far too massive for this sort of practice. Dudes pulling on chains is just an aesthetic conceit of the universe.

The Imperium does that because it's cheaper to enslave humans that to bulit cranes or something else to do it.After all manpower is the most abundant resource that the Imperium has.

[Darth Hoth]

But 21 PERAtons sounds absurdly over the top for a Nova cannon...

A nova cannon is essentially stated to fire extremely large projectiles at essentially .99c. However, I'm not sure we should take 'extremely large' to mean '80 000 tons'.

.99 c? When last I heard, it was "near light-speed" or similar vague phrasings. Are there new sources that I am unaware of?

[Eleventh Century Remnant]

To do significant damage in the manner in which it is usually said to do- a blast effect potentially capable of melting a shielded, multi- kilometre, billion-plus ton warship maybe ten thousand kilometres from the detonation point; working backwards from that to how much mass has to convert to energy, nova cannon rounds are big. A few percent of the second-by-second mass consumption of the sun seems not out of place.

The question then becomes where you think the anomaly is. Despite appearances, Newton has not been repealed in the galaxy of the 41st Millennium, and how a ship is supposed to survive the shock of (or for that matter survive the energy density necessary for) launching a nova round beats the crap out of me. If you assume the ship can take that strain, then it has to be that tough, which means the amount of energy required to melt them goes through the roof, which means the size of the nova cannon round and the stress it imposes on the firing vessel... et cetera.

Even at a minimum estimate, a direct hit by a nova cannon on practically any vessel target would make detonation superfluous- the opposite is also true. Their ability to reach the target may be compromised by their speed- a direct hit by a small molecule at near-c wouldn't do the nova cannon round any good either. That passage that categorises them as implosion rather than detonation weapons just makes things even more baffling.

As far as I remember, planetary extermination is actually quite easy in 40K, being mostly bioweapon based and an ordnance task- anything that can carry torpedoes, from Cobras on up, can deliver biosphere exterminating virus warheads. There are alternatives- for use on hive worlds that have mostly wiped out their own ecologies already, there have to be- but how efficient they are, how many cyclonic bombs it takes, not sure. I suspect a plot device's worth.

A thought; what do cyclonics have in common with that old school stick o'fun, the vortex bomb- which was essentially a warhead that opened a rift into the warp, which wandered around the battlefield, swelled, shrunk, fissioned, moved, merged, dissipated, etc, quite unpredictably? Vortex, cyclone...hmmm.

[Simon_Jester]

If the more insane figures for the nova cannon's size are true, it's quite possible that the shell mounts enough integral shielding to handle passage through space. That said, it would still have problems if the enemy started throwing up serious point defense.

[hongi]

So which is it? Do nova cannons shoot black hole projectiles or do they shoot projectiles that have a blast effect?

[Black Admiral]

So which is it? Do nova cannons shoot black hole projectiles or do they shoot projectiles that have a blast effect?

Both singularity and blast-implosion shells; there is also a variant of the capital ship-scale Nova Cannon which fires energy beams (mounted on the Great Crusade-era Infernus-class battleships). "Nova Cannon" apparently refers to a whole family of weapons, not just the one - the Armageddon-pattern Ordinatus mounts a Nova Cannon as well, but it's a rather smaller scale device than the shipboard ones (and, again, fires energy beams, not shells - rather powerful for a ground weapon, too, being capable of vaporising a Mega-Gargant outright).

[IvanTih]

So which is it? Do nova cannons shoot black hole projectiles or do they shoot projectiles that have a blast effect?

Both singularity and blast-implosion shells; there is also a variant of the capital ship-scale Nova Cannon which fires energy beams (mounted on the Great Crusade-era Infernus-class battleships). "Nova Cannon" apparently refers to a whole family of weapons, not just the one - the Armageddon-pattern Ordinatus mounts a Nova Cannon as well, but it's a rather smaller scale device than the shipboard ones (and, again, fires energy beams, not shells - rather powerful for a ground weapon, too, being capable of vaporising a Mega-Gargant outright).

What is the source for the Nova Cannon on Infernus?
That Nova Cannon on Ordinatus fires plasma.

[Serafina]

Nova-cannon is just a general term for a large gun that fires an extreme-speed projectile or beam that causes a lot of area damage.
The term is most often used for the front weapons of cruisers and/or battleships which fire near-lightspeed massive projectiles that somehow fracture at a pre-defined position to cause a lot of area damage.

[Black Admiral]

So which is it? Do nova cannons shoot black hole projectiles or do they shoot projectiles that have a blast effect?

Both singularity and blast-implosion shells; there is also a variant of the capital ship-scale Nova Cannon which fires energy beams (mounted on the Great Crusade-era Infernus-class battleships). "Nova Cannon" apparently refers to a whole family of weapons, not just the one - the Armageddon-pattern Ordinatus mounts a Nova Cannon as well, but it's a rather smaller scale device than the shipboard ones (and, again, fires energy beams, not shells - rather powerful for a ground weapon, too, being capable of vaporising a Mega-Gargant outright).

What is the source for the Nova Cannon on Infernus?

Dark Creed;

An Infernus-class battleship, one of the largest vessels to have fought in the Great Crusade, the Crucius Maledictus was the flagship of the Dark Apostle Ekodas.
- pg. 15

The nova cannon of the Crucius Maledictus roared like an angry god, and a massive blaze of light comparable to the output of a small sun surrounded its barrel as it fired. The beam of blinding light tore through the Imperial line, engulfing two cruisers and an escort, ripping them apart with seeming disdain.
- pg. 101

That Nova Cannon on Ordinatus fires plasma.

Yes, that was my point.

Nova-cannon is just a general term for a large gun that fires an extreme-speed projectile or beam that causes a lot of area damage.
The term is most often used for the front weapons of cruisers and/or battleships which fire near-lightspeed massive projectiles that somehow fracture at a pre-defined position to cause a lot of area damage.

The singularity & blast-implosion type shells both, well, implode at a pre-set distance from the firing ship.

[IvanTih]

That Nova Cannon on Ordinatus fires plasma.

Yes, that was my point.

I know,I just wanted to specify that the Ordinatus fired plasma since there are several types of energy weapons in the 40k.

[Eleventh Century Remnant]

A thought occurs to me, and it is based on the canonical description in the Battlefleet Gothic rules, of nova cannon rounds as being electrogravitically accelerated. If you assume the things are Heim-Droscher Drive projectiles, and a better fit for '"electrogravitic" I cannot think of, then a lot of difficulties fall into place. Too many, maybe- it's so neat a solution I'm beginning to doubt it myself.

Basically, the theory (which is genuine fringe science, although I doubt if it is what Games Workshop had in mind) suggests that an immensely powerful spinning magnetic field can have a gravitic effect- that there is an equivalence which can be exploited.

The magnetic, very large coilgun, barrel accelerates the shell, but it also gets it up past the field densities for this electrogravitic field to form- and that forms a sort of sublight warp (in the Trek sense rather than 40K) that gives the shell most of it's speed, sparing the firing ship from being torn to bits by the recoil, protecting it in flight, and now we get to the really clever bit.

In some, the more primitive maybe, marks of nova cannon, the shell has a charge that behaves in the same way as the plasma in a plasma reactor- something pretty exotic's actually happening in there, the plasma is just the interaction medium, it's energised by the exotic reaction and kaboom, traditional sunflare type.

With other more advanced examples, there is no shell filler, the thing's just one big Heim generator, and the timed overload, flare and collapse of the gravitic warp field is the effect.
For the little ones, of course, (or for the big ones whern you've run out of ammo), just squirt a bunch of hot hydrogen atoms into the breech rather than a shell and let the magnetic accelerator barrel do the rest.

Too neat to be true?

[Ryan Thunder]

I can't provide a source because this is second-hand, but a nova cannon can supposedly vapourize an eleven-kilometer asteroid.

Using the asteroid destruction calculator on the main site I get the following values; For a granite asteroid, 5.11 teratons. For a nickel-iron asteroid, 9.96 teratons. For a ball of ice, 424 gigatons.

I'll assume that;
1) the asteroid is a perfect sphere.
2) that the nova cannon shell was aimed directly at the centre of that sphere.
3) the shell activated at an altitude of 1 metre above the surface of the sphere.

This means that 49% of the energy released by the shell was expended on the asteroid, giving us a lower limit of 864 gigatons, or 3.63 billion terajoules.

[IvanTih]

Don't know is this calc correct it comes from Factpile from L-W.

A Nova cannon is a huge weapon, normally mounted in the prow of a ship so that the recoil it generates can be compensated for by the vessel’s engines. It fires a proejctile at incredible velocity, using graviometric impellers to accelerate it to close to light speed. The projectile implodes at a preset distance after firing, unleashing a force more potent than a dozen plasma bombs.”

- Battlefleet Gothic

Take note of how the ship has to compensate engine thrust to counter recoil – in a vacuum!

I would generally assume “close to light-speed” to mean at least 80-90% of C. The size of a Nova cannon shell is never given precisely, but the diameter of the shell is given in other sources (Fifty meters in “Warriors of Ultramar”), though a 30 meter diameter nova cannon is mentioned. Mass can be derived by assuming the length is at least equal to the diameter, or (more probably) a multiple of the diameter (2-3x longer than the diameter, for example. A fifty meter diameter shell would be a hundred and fifty meters long).

Example: Going by a 50×150 meter shell made of Iron (assume 30% solid, its supposed to be packed with explosive of unknown type and density) fired at .9c yields a shell mass of around 770,000 tons and and a kinetic energy rating of 90,000,000,000 petajoules (Holy shit!).

Giving the blast of a Nova cannon (The most powerful ship mounted Imperial weapon) a staggering yield of 22 petatons. For those of you struggling to comprehend these figures, this is a yield one million times greater than the heaviest Turbolaser available to the Star Wars universe.

Or for those less fantastically inclined, two to three million times the combined explosive power of every nuclear weapon on Earth throughout history.

http://www.factpile.com/retribution-cla ... /#comments

[Batman]

Horseradish? Assuming 50% reactor power delivered to guns a measly ISD1 can do 0.7PT a second and that's not even a real capital ship.
An Acclamator can do between 1.2 and 4.8 TT per broadside and that's not even a real fighting ship. One million times the yield of the largest turbolaser my ass.

[Eleventh Century Remnant]

Closer to a factor of seven, actually- http://starwars.wikia.com/wiki/W-165_pl ... turbolaser, quoted from the NEGTW as 1.46E25 W. Single barrel.

Beisdes, nova cannon as mentioned repeatedly are not direct impact weapons. Unguided, the chances of their making direct contact with a target are very low. It's the energy of the explosive filler, or physics package if you prefer, that matters in almost all cases.

[Darth Ruinus]

Closer to a factor of seven, actually- http://starwars.wikia.com/wiki/W-165_pl ... turbolaser, quoted from the NEGTW as 1.46E25 W. Single barrel.

Do you have this actual quote? I'd like to see it, since the article you linked to has no such firepower figure.

[Ford Prefect]

.99 c? When last I heard, it was "near light-speed" or similar vague phrasings. Are there new sources that I am unaware of?

Every statement is 'close to light speed' 'something approaching the speed of light' etc etc. I'm fairly sure that the Battlefleet Gothic rulebook actually says 'at lightspeed', which was the first source I've ever read on the matter. I don't think saying that it's .99c is exactly controversial, given that is, in fact, 'close to the speed of light'' while .9c really isn't.