Sky-Watcher SynScan V3 Hand Controller User Manual

Page 16

PART III : ALIGNMENT

Eyepiece
It is very important to put the alignment stars at the center (or the same spot) of the FOV of the

telescope’s eyepiece during the alignment process. Thus,
• It is recommended that a reticle eyepiece is used for alignment.
• If a reticle eyepiece is not available, try to use an eyepiece with shorter focal length to yield

a smaller FOV. Users can defocus the telescope to obtain a large star disk in the FOV.

Centering the star disk in the FOV is easier than centering a sharp star.

• During the alignment process, avoid changing or rotating the eyepiece and the diagonal

mirror.

Mechanical Backlash
All mounts have more or less mechanical backlash on both axes. To avoid introducing align-

ment error from backlash, users should keep the following rules in mind:
• When centering an alignment star in the eyepiece, the operation should always end by

using the

and

RIGHT

direction keys to move the axes.

• If there is overshoot when centering alignment star in eyepiece with

RIGHT

keys, use

the

LEFT

DOWN

keys to pull the star back to the edge of the FOV and then use the

RIGHT

keys to center the star again.

Alignment Stars Selection
The choice of alignment stars might also impact the alignment accuracy. Please refer to

Sec-

tion 3.7

on the rules of choosing alignment stars for various mounts and alignment methods.

3.6 Tips for Improving Alignment Accuracy

Rules for choosing an alignment star:
• Choose an alignment star with smaller declination. It will help to obtain higher resolu-

tion in R.A. movement in the telescope’s eyepiece.

• If there is cone error in the telescope-mount setup or if users are not sure about it, it is

recommended to choose an alignment star that is close to the object(s) to be observed.

Advantage: Quickest alignment.
Preconditions:
• An accurate polar alignment for the mount.
• Small cone error in the telescope-mount setup.

If the cone error is large, there will be noticeable offset in the R.A. when the SynScan

hand control locates an object which is:

Equatorial Mount with 1-Star Alignment:

3.7 Comparison of Alignment Methods

On the other side of the meridian from the alignment star

Deviated significantly with the alignment star in declination.