On the fourth day I finally felt confident that I had really solid polar alignment - mostly because I had been doing it for 3 nights straight. I use a method that relies upon shots taken in the south and the east.
I start out by roughly polar aligning the mount to Polaris. Having a polar alignment scope can help immensely in this initial alignment step. Then, to begin the procedure, I point the telescope with the camera to the south, about 10-15 deg above the horizon. Then I do a short test exposure of about 50 seconds. For the first ten seconds, I just let the exposure run as is. Then for 20 seconds, I press the left button on the mount keypad. I should preface this by saying that I've set the mount control speed to either the lowest or next to the lowest setting on the hand controller. Then after the 20 seconds have passed, I press the right button.
The following image is a result of the above procedure:
What you end up with is a bunch of lines that have a "head" or dot at one end. That dot was created by the initial 10 second exposure and the lines represent the movement caused by your hand controller.
A closeup of the left upper corner reveals an interesting picture:
In the middle of the closeup you can see a golden line created by a star. As mentioned above, the dot is a result of the 10 second hold at the beginning of the image. Then you see the line going down that was a result of pressing the left button on the mount keypad. As you notice there are two lines which is the result of pressing the right button. The line connected to the dot is the line made by the left button and the incomplete line is made by the right button. What's important here is the GAP between the two lines. What you're trying to accomplish is a "collapse" of that double line into a single line.
How do you that? If the scope is pointing to the south, then you move your azimuth (left-right adjustment) on your mount just a little bit. Then you repeat the above procedure to see if that gap between the two lines has increased or decreased. After a few iterations, you should be able to collapse that gap so that it's just one solid line coming from the dot.
Once you've accomplished this you move the scope to the east about the same angle above the horizon and repeat the procedure. EXCEPT now you are making physical adjustments to the altitude (up-down adjustment) of the mount. The same phenomenon will occur. As your lines collapse, you approach the appropriate altitude for good polar alignment.
To further refine the polar alignment you can increase the time interval for creating those lines above. After I collapse the lines at 50 seconds, I will typically go back and do the same procedure at 170 seconds. When you are satisfied with 170 seconds in both azimuth and altitude, then you should have good enough polar alignment for an unguided 2 min shot. And it's certainly good enough for autoguiding.
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