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Doing a polar alignment is a big problem for most with a portable equatorial mount mount in the field. However a lot of time can be saved if you start off in a good manner.
Drift aligning using a star at the zenith will get your azimuth correct relatively easy but getting the elevation can be very time consuming as the calibration for elevation is usually difficult to read out with any precision or accuracy from the built in scales and drift aligning at the horizon is often impossible due to visibility.
When doing a polar alignment the most import first procedure is to get the elevation in the "ball park". 30 arc minutes will be good enough for astro photography up to about 3 hours. Measuring the elevation was quite a task in the past but now we can get digital inclinometers that can set the elevation quickly to about 20 arc minutes. The azimuth can then be set within a degree or two using a compass.
With this sort of elevation accuracy the drift alignment at the zenith can be quickly completed with programs like PHD and have you ready to take photos in about 15 minutes from initial set up ignoring any further elevation corrections.
If your mount is to be permanent getting the alignment much closer can be achieved using more precise techniques to get the alignment spot on but cone error may also need to be corrected. this will also improve your gotos.
Barry
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