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Drift Align using PHD

PostPosted: Sat Aug 13, 2011 4:55 pm
by martin_h
The process begins as all the other drift alignments. To check the RA alignment chose a star at 0° elevation close to the meridian. To set the DEC alignment choose a star as close to the E or W horizon as possible.

Turn on the guiding program (PHD) , select the mount and camera and run through your calibration as usual.

To Check the RA select a star near the Meridian at 0° elevation. (or as close as you can get)
Start Guiding on the selected star.
Turn on the GRAPH and select DX/DY instead of RA/DEC.
Turn off the DEC guiding
If your mount is perfectly aligned the DY ( red line) should track across the graph near the center line. If it drifts up or down you need to make a very small adjustment to your AZIMUTH screws to compensate for that. You will see the change immediately. No need to wait 5 or 10 minutes for the visual drift.
Now set up the elevation.
Stop the guiding and look for a star near the western or eastern horizon at whatever elevation allows you to clear any obstruction. The lower the better.
Recalibrate the guiding on the new star.
As in step 3,4 & 5 above start guiding and make sure that the DEC guiding is off.
Once again if your alignment is on then the DY trace should not drift from the horizontal graph line. If it does, carefully make small adjusts to the ELEVATION screws to compensate. Again you should see an immediate change in the graph.
Repeat as nessissary.

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