PHD2 Drift alignment confusion

[rubecula]

Last time out I did a PHD2 drift alignment and whilst I was able to track for 5 minutes the graph was all over the place.  So I thought I'd have another go tonight.  To check that I was doing it right I looked at this video:

 

 

In it the guy says when you adjust the mount you should try to get the star half way between it's current position and the magenta circle.

In the Drift Align pdf from the PHD2 website (http://openphdguiding.org/tutorial-drift-alignment-with-phd2/) the instructions say move the star all the way to the magenta circle.  Which is correct?  I was just wondering that if I was overcorrecting by going all the way to the circle, but I would have expected the PHD2 doc to be correct.

[Owmuchonomy]

I drift align with PHD2 but I must admit I have never come across a purple circle.  I get drift trend lines which tell me which way the drift is.  I then tweak the mount a little, run it again for a few minute and see if it is better or worse.  After a few repeats you get to know which way to adjust the mount and get your drift lines level.  Purple circles? Beats me.

[Ken82]

I've used the purple lines on the live view screen although as owmuchonomy mentions it's best to just concentrate on the drift lines . Remember to only adjust the red (Dec) line . 

[Leveye]

Use bookmarks as well to remember and fine tune it even more precisely. It worked wonders for my mount.

http://www.cloudynights.com/topic/472874-drift-alignment-with-phd2-the-bookmark-technique/

[rubecula]

Thanks Leveye, that looks really useful

[Leveye]

Most welcome!

[Leveye]

Quote from the official PHD2 guide on drift alignment tool

"

• The solid magenta circle becomes a dashed-line magenta circle. The dashed magenta circle represents a limit to how far the guide star needs to move, not the exact distance. We only know that the star should not move past the circle. Rather than moving the star all the way to the circle, you may want to only move it half-way or so as an initial guess.  You can use Bookmarks to keep track of where the guide star was in each Drift/Adjust iteration.

"