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Drift alignment - took me months to get the hang of - reading from a book or website and mistaking terms. If you can - get a friend who knows what he's doing to show you - or visit an astro party and learn there.
If you can rig a permament peir somewhere you have a HUGE advantage. You can tune your gear to be within arc seconds of the SCP - which means pointing and tracking will be excellent right off the bat.
There are alot of automated tools for polar alignment, some free, some a 30 day trial some cost. I used PEMPro and it did the job well for me.
The process - in the simplest laymans terms:
1. Get you mount set up as best guess you can level and pointing towards SCP.
2. Put in your guiding eye-piece and orientate it so RA movement takes any centred star exacly along two of the lanes precisely.
Now in all the following steps ignore RA drift - its only DEC drift (that 90 degress opposite to RA drift you are correcting for).
3. Find a star about 20 - 30 degrees above the horizon - as due East as you can. Centre it in you eyepiece.
Have a stop watch or egg timer and monitor after say 5 minutes how far it drifted in DEC only (and in which direction).
4. Drift means your elevation is wrong - one direction your above SCP, the other direct below SCP.
I cheat - guess and adjust your elevation say 1 degree. Now re-centre your star and time its drift for another 5 minutes.
It will either show alot more drift (in the same direction - meaning you guessed whether to raise or lower elevation incorrectly), less drift (meaning you guessed right - keep going but in smaller increments) or now its drifting in the other direction (you over compensated, wind it back some way).
Keep adjusting height - re-centre star and measure drift again.
5. Once you are happy there is no DEC drift for 5 - 10 minutes - simply swing the scope in RA only until your tube - weights arm is parallel to the ground. To clarify if you point the scope due East at the horizon, then swing the scope in RA only through 90 degrees - that is the best spot to check for East/West misalignment.
6. Find a star around this location - centre it and time it for 5 minutes - looking only for DEC drift.
If you get drift in DEC - you need to adjust the East/West orientation of the scope. Again guess one - if it right you'll see less drift once you re-centre the star and time it again for 5 minutes. Guess wrong and there'll be more drift.
Keep looping like step 4 until you see no DEC drift.
7. Now go back to step 4 - star above the Eastern horizon and do it again - adjusting elevation only. Once that is nailed go vertical again and nail East/West orientation. You'll find your adjustments get smaller and smaller as you bear in one the exact SCP on both axes of your mount.
Generally 2-3 iterations of the above should be sufficient to get you very close to the SCP.
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An automated program checks your orientation - measures angular size for your camera and following the same procedure tells you or even shows you how far to adjust your scope and in which direction. So with PEMPro I might do a 30 minute run on either axis and look to get less than 5 arc seconds DEC drift. I will still need to guide long shots (to even out Periodic error and atomspheric seeing errors) but the guiding will be alot simpler and much less frequently - meaning it should be far easier getting great shots.
Hope this helps!
Matt
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