Excuse my stupidity but I have a question!  I have a Meade 10" reflector on equatorial mount.  How long of an exposure can I take if my polar aligning process is simply setting the elevation and pointing it at the North star.  The "official" polar alignment technique just sounds to painful to me!

Thank you.

At prime? With the FL you got, maybe between a 1/4 and 1 second. 

 John's right, not aligning your scope will result in terrible tracking. Familiarize yourself with the procedure and try it a few times. It's really not as hard as it may seem. Once you've done it a few times, it will come like clockwork. Do your initial alignment with two or three stars, if you have that option, and it doesn't hurt to add a calibrating star or two as well.

John's right, or probably even being a little optimistic. Just pointing the mount isn't going to do anything for you. Everything will probably start to drift immediately. You might not see it with your eyes at an eyepiece, but the camera will probably pick up on it almost instantly.  

Balance and polar alignment are crucial for astrophotography. And depending on the method of polar alignment level can also be a factor. Generally that's not important as long as you have accurate polar alignment. 

If you're planning on astrophotography you really should take the time, Like Kevin pointed out, after you have done it a couple times it will become second nature. Your resulting images will reflect your time and patience.

Proper balance and Polar alignment isn't difficult. Even if you don't have a polar finder/alignment scope. Just use the Drift method. Two or three iterations of that and you should be able to get some pretty decent exposures.  And if your mount has PEC you should be able to train it enabling you to get relatively longer exposures.

Additionally, unless you have a super heavy duty mount, you will need to worry about any significant amount of wind using a 10" Newtonian.  The cross-section presented by that telescope is going to be like a sheet in the wind.  A good little breeze can ruin a good shot. 

Have A Nice _________ 

True enough.  Don't know which 10" reflector rig you have, but it would be well worth your time to learn polar alignment. Even if you can get to within about 1/2°, you could piggy back a camera with a short FL lens and begin getting some acceptable photos.

Then find out about drift alignment and perfect the procedure.

Last night, after putting a scope together after some repairs, my PA was off just enough that it took over 150X to see it. A test shot of only 10 seconds showed star trailing.