Drift alignment can be a long and painstaking process, but it's necessary for astrophotography. After an initial 30-minute measuring session, this method will have you accurately drift aligned in just over 10 minutes!

What is Drift Alignment?

Principle & Theory

Initial Requirements

Here's what you need to use:

1. a $2 laser pointer
   
   
2. some steel-reinforced epoxy
   
   
3. a darkened photocopy (or one with black lines) of an 8½ x 11 sheet of graph paper (1/4" quadruled works well)
   
   
4. a clear plastic "protector sleeve" or laminator for the graph paper
   
   
5. a piece of plywood or aspenite a little larger than the graph paper
   
   
6. a small L-bracket and a ¼:20 nut (or drill/tap a hole in the bracket to ¼:20
   
   
7. a couple of short screws (to fasten the L-bracket to the plywood)
   
   
8. four tacks (to pin the graph paper to the plywood)
   
   
9. a camera tripod
   
   
10. 2 strips of black electrical tape, 1-2" long (fold the end over a tad so it's easy to remove)
    
    
11. a fine-tipped dry-erase/whiteboard marker
    
    
12. K3CCDtools for drift explorer function
    
    
13. A piece of string to keep future target setups at the same distance from your mount

One-time preparation:

1. Epoxy a $2 laser pointer to the mount (it should move around as you adjust the alt/az but not when you move RA/DEC).
   Note: it's best to select an orientation for the laser that would normally project the beam onto a stationary surface like a wall, fence, tree if you often set up at the same location.
   ---For a good example of an installation, see Mike Gray's page here.
   Note: You MAY be able to temporarily attach (via electrical tape wrapped around it and the mount, for example) a collimating laser to your mount for a less-permanent solution.
   
2. Take a piece of 8½ x 11 graph paper (¼" quadruled) and photocopy it so the lines are black.
   
   
3. Either laminate the graph paper or put it in a plastic protector sleeve
   
   
4. Screw the L-bracket to the backside of the plywood near the bottom (landscape orientation) so it can be fixed to the camera tripod with the ¼:20 nut.
   
   
5. Pin the laminated/sleeved graph paper onto your plywood (again, landscape orientation)
   
   

Now for the procedure...

Set up the graph paper target on the tripod so the laser hits it somewhere around the middle of the paper (preferably on a line/line intersection) (somewhere around 10 feet from the mount is fine). Using the drift explorer function of K3CCDtools, track a southern star on the meridian for 5 minutes with your camera, and write down the accumulated DEC drift (**unless your RA axis is horizontal on the screen, you may want to perform drift explorer's angle calculation function first while turning off your tracking). Move the mount so that the laser beam hits the graph paper FIVE SQUARES (5 instead of 1 increases the overall accuracy, but this has nothing to do with the 5-minute drift period) to the left of where it did previously, and redo the 5-minute session, noting the NEW DEC drift. The difference between the 2 results, divided by 5 is your "DEC DRIFT PER SQUARE" - WRITE THIS DOWN FOR FUTURE USE. Calculate how many squares are needed to compensate for the total DEC drift noted during the last 5-minute session, and move the mount accordingly. Azimuth alignment complete! Repeat the process with a star low in the east or west, for altitude (latitude) adjustment (obviously you move the beam VERTICALLY instead). AGAIN, WRITE THIS DOWN FOR FUTURE USE - NOTE IT'S FOR THE ALTITUDE ALIGNMENT AND WILL LIKELY BE DIFFERENT. Now, before you pack things up, get a roll of string, and cut a piece about two feet longer than the distance between your mount and your "target" tripod. Tie a slip-knot on one end, and loop it around your mount. Gently extend the string out to your "target" tripod location, and cut it to length so it just touches the graph paper. By using this same distance between your mount ant the tripod EACH TIME, the DRIFT PER SQUARE (DPS) in each axis will remain CONSTANT!

FUTURE drift alignments at any location (using the string for correct distance) will take just over 10 minutes, since you'll only have to measure drift on each axis ONE TIME (provided you've recorded the DPS values).

Additional Notes:

I found it easiest to mark the laser starting points with a fine point dry-erase (whiteboard) marker. Then to make things easier, make a vertical or horizontal "white line" on the laminated graph paper where you want to MOVE the beam to, with a strip of black electrical tape.

For example, if you're moving over ONE square to the left, put the black tape strip vertically on the laminated target, immediately to the right of the point where you want to move the beam to. This creates a reflective white vertical "target zone" that's very easy to see when you get there, regardless of distance to the tripod/graph paper.

Also, once you've got your axis alignment for your camera sorted out (rotation), MARK some line-up matching points on your camera and drawtube/ep holder so you don't need to do this each time. You'll need to do the same with your OTA and its rings if it can be rotated. This is a SIGNIFICANT time-saver.

For higher accuracy, move the target/tripod further away during the process (don't forget to redefine your DPS values).