Re: 2-3 star alignment.

Khalid Baheyeldin

I don't have a specific answer for your question, which is vague. Are you asking specifically
about when the mount is not leveled correctly?

But here is some info:

The first star alignment just brings the celestial sphere and the internal coordinates

Internally, OnStep calculates the following errors:

  ax1Cor=0;  // align internal index for Axis1
  ax2Cor=0;  // align internal index for Axis2
  altCor=0;  // for geometric coordinate correction/align, - is below the pole, + above
  azmCor=0;  // - is right of the pole, + is left
  doCor =0;  // declination/optics orthogonal correction
  pdCor =0;  // declination/polar orthogonal correction
  dfCor =0;  // fork or declination axis flex
  tfCor =0;  // tube flex

The altCor and azmCor are the errors in Altitude and Azimuth (mount not perfectly
aligned with celestial pole). To calculate these, you need at least a 3 star align. So,
this is the minimum number you should use for accurate gotos.

The more stars you align on, the better the alignment. All boards offer a 6 star align,
and you can increase that in the Config file (at the expense of a couple of minutes
of slowness while the calculations are being done).

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