The amperage makes no difference, so that's fine.
The problem is that power supply isn't 12V, it's "12V" meaning automotive voltage, which is really 13.8V (what your car produces while running). I don't know if the Meade GPS scopes are so sensitive that 12 vs 13.8 would be a problem, but I'd make sure before using that one.
Looking at the Meade #07043 DC adapter (cigarette adapter), I doubt it has anything like a voltage regulator in it. I seriously hope it has some overprotection components, like a TVS diode.
Automotive power is nasty business. 12V is spec, 14V is a nominal. Transient voltage spikes >100V are also to be expected. It is probably never a good idea to use a telescope with a car that is running or cranking while the telescope is plugged in. (Modern cars might be a little better in this regard, but electronics are "automotive spec" for a reason.)