Sky-Watcher SynScan V4 Hand Controller - Manual (Page 40)

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PART XI : ADVANCED FUNCTIONS
11.6 Calibrating Auto-Home Offset
• Press “ 1 ” key to keep the original Home Position Offset.
• Press “ 2 ” to use the results obtained from the 1-star alignment to calibrate the home
position offset.
1. PEC can only compensate tracking errors on the R.A. axis. Therefore, a precise polar
alignment is still required to track minor errors on the Dec. axis.
2. After turning on the PEC replay, it is recommended to wait for at least one cycle time
of the period error before taking a picture.
3. To re-use the PEC data on a mount which supports SPEC, users should park the tele-
scope before shutting off power (refer to Section 11.1) . This limitation does not apply to
the mounts which support PPEC.
Some Sky-Watcher’s equatorial mounts (ex. the EQ 8 mount) has the Auto-Home function
which can set the mount to a standard home position after turning on the power.
The offset of the home position can be calibrated and compensated with the following
procedures:
1. Polar-align the equatorial mount accurately.
2. Turn off the power, and then turn it on again, and then initialize the hand control.
3. When SynScan hand control asks “ Auto-Home? ”, press the “ 1 ” key to execute the au-
to-home process.
4. Finish the subsequent initialization steps.
5. At the end of the initialization, choose 1-star alignment to align the mount.
6. At the end of the 1-star alignment, the hand control will ask “ Update H.P.O? 1)No 2) Yes ”
(The “ H.P.O. ” means Home Position Offset).
11.7 Setting Cone Error and Non-Perpendicular Error
• Cone error (CE) occurs when a telescope’s optical axis is not perpendicular to the equato-
rial mount’s declination axis (or the altitude-azimuth mount’s altitude axis).
• Non-perpendicular error (NPE) occurs when the mount’s two axes are not orthogonal.
Without proper compensation, both of the above errors could lead to inaccurate pointing when
the telescope system tries to locate a celestial object automatically. The value of these errors
can be set on the hand control for compensation.
1. Access menu “Setup\Alignment\Cone Error“ to display and modify the cone error.
• The cone error compensation will be applied to 1-Star, 2-Star and Brightest-Star align-
ments.
• In a 3-Star alignment, SynScan hand control measures the current cone error and over-
writes the old cone error value.
• Cone error is quite common in most telescope systems, but and alt-az mount is less
sensitive to cone error. Generally, user can set cone error to 0 on a alt-az mount.
2. Access menu “Setup\Alignment\NP Error“ to display and modify non-perpendicular error.