ChrisRowland wrote: This is not correct. The axes used for the correction matter. If it didn't and any way of moving the scope to put the target star in the calculaed position was OK you could use Ra and Dec movements to do this. This would obviously have no effect on the polar alignment.


It is correct. The PA routine works anywhere on Earth at any given time. In other words, for any given orientation and rotation of the mount wrt the rotation axis of the Earth. Therefore in a local frame it doesn’t matter at all if the mount is rotated (i.e. not level).

The fact that you cannot use RA and Dec to align the mount is because you are using the fine adjustment knobs to align the RA axis with the rotation axis of the Earth as well as possible. By doing so you compensate for the mount not being level by moving both axes. A remaining rotation over the Dec axis once the PA routine has completed results in a difference in local sidereal time which the mount and Ekos will correct for as soon as you do a star alignment or a plate solve with either Sync or Slew To Target enabled.

If this were not true then the previous implemtentation of the PA routine with the pink line between the location in the FOV where the star currently is and where it should be for perfect PA wouldn’t work as well. Both that ponk line and the new lines, that are split up over corrections in azimuth and altitude, are merely projections to help you get the PA done as well as possible. It could have been a swirling line all over the FOV or even outside of it and it still would have worked.

The only thing that matters is to get the star from where it was in the FOV to where it needs to be as well as possible. How you do that is irrelevent.

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