So, on Hoth, they can use the ion cannon to take out a star destroyer, but why didnt they just use the damn thing to take out the walkers?

probably couldn't aim that low

Because then they would have won the battle and the empire would have struck back.

I thought the Ion cannon only disabled them for a very short period of time so the transports could get past them. I'm not seeing how that would be terribly useful against walkers.

JTH is right

where's that picture that has the Simpsons / Xena character at some geek Con...

sigh..... wizards...

I've never really considered this before, and this may be a stretch, but it seems like the walkers were approaching from the opposite side of the base that the ion cannon is on. If you'll recall, Luke and the other pilots are making a rather leisurely departure in their x-wings after Imperial troops have entered the base. If the ship hangers are all on that side, than the cannon would be on that side and pointing mostly up. It simply may not have been able to turn and fire at that angle.

If they could of disabled the walkers, it would of given the snowspeeders a better chance of using their harpoon cables.

i think the Ion Connon was more of a large scale weapon. For example, you wouldn't use a nuclear warhead to take out a tank.

When the Empire suddenly arrived in the Hoth system, the besieged Rebels needed to buy time for their evacuating transports. They used an immense heavy ion cannon to provide covering fire for the escaping vessels. Powerful blasts from the heavy ion cannon momentarily disabled an Imperial Star Destroyer during the early moments of the Battle of Hoth.
http://www.starwars.com/databank/tec...eavyioncannon/

That's not in question


I still think it's just a technical issue, it was on the wrong side of Pinnacle base.

I think that's it. Even though stormtroopers are lousy shots, they're not dumb enough to walk into the fire zone of an ion cannon.