If your mount begins the PA routine from the Park (or Home) positions, then, when you come to see the correction vectors, the scopes have rotated by 60° to the West (or East). Therefore Alt and Az mechanical adjustments will move the chosen star along lines which are 60° rotated from vertical and horizontal on your display. If you want to avoid this you should start the PA process from a pre-rotated start position 60° to the East (or West). I have tried this, but in the end I've just accepted that the green and yellow vectors are the directions of the Alt and Az adjustments. ,
Could you explain a little more? You say your star follows the purple line when you're correcting polar alignment. Is that with the Alt knob, or the Az knob, or both? If you're pointed somewhere near the pole, those two knobs should move your telescope is orthogonal directions, so it would be surprising that they both move the star along the purple line. If almost all of your alignment error is in one of the axes, then moving the offending knob, would, of course be pretty similar to the purple line.
As an experiment, you might intentionally misalign both axes by, say, 20 or 30 arc-minutes and see if you still get the same behavior.
FWIW, at least for my setup, I don't believe the numbers much for anything under 1 arc-minute, or perhaps half that. I wouldn't recommend thinking about arc-seconds.
Sorry, I was not clear in my description of what I think is the problem. I (myself) try to follow the purple line to the crosshair and use both knobs for this. So the workflow for me is basically like in the previous version. The movement of the Alt and Az knobs itself is at least close to orthogonal. So with a bit of trial and error I make my way along the purple line using the knobs for Alt and AZ.
With the split into Alt and AZ components in the display that you implemented my expectation was that I could use this decomposition of the Alt and Az component for the correction. So when I select a star I expected to move only Alt along the yellow line to the edge of the triangle, then only Az along the green line to the crosshair. So only care about one direction at a time. But when moving my Altidude screw on the mount the stars do not move parallel to the yellow line. Same applies to AZ not parallel to the green line.
Wrong expectation that I could move the selected star along the indicated lines, separating the Alt and AZ correction? Do I need to slew back to home before using the hardware knobs as the calculation of the vectors is based on the first position?
In case this is relevant: I start in the home position and slew 30 degrees east with each step so when I start turning the hardware knobs the mount is rotated by 60 degrees. I could see Polaris from where I set up my mount and start close to the pole. At the moment I use my main scope for the polar alignment(432 mm focal length, camera ASI 533MC). I'm not striving for extreme precision below an arcminute.
I was using this feature last night in the northern hemisphere and doing a polar alignment away from the pole. I found the correction vectors recommended wherein the wrong direction. Also adjusting say Altitude the star never travelled along the yellow line or anywhere near it. So what I ended up doing was looking at the length of each vector and then moving the star that length for the corresponding direction.
I am using a Celestron AVX mount connected via HC and a 6 " RC scope with an AA26C camera. KSTARS is 3.5.2 stable build.
Is there something I need to check or configure to correct this performance?
As the problem that I experience is somewhat similar to what
describes (when turning the knobs on my EQ6R the movement of the stars is not alligned to the vectors displayed): what log should be activated to be able to record helpful input here? The weather might allow me to have a session in the next days so I might be able to get some data that might be valuabe to help to narrow it down.
Sorry I found it after that I wrote the post. At this time I am going out of mind with my EQ6 mount that is not stable on the tripod base, I can't lock it after each azimuth correction during the polar alignment procedure