to the StarGO (see Appendix, section A2.3), every Sync operation performed after
the restart contributes to build the model. For example, if during an observing
section, a certain number “n” of Syncs is performed, a n/24 model is progressively
built. If a new model or an existing one has been loaded in memory, each additional
Sync will increase the number of stars of the model up to the total of 24. In order for
this incremental feature to have the correct effect, the operations MUST be started
with the mount in the Synch Home Position as explained below.
NOTE: To perform a Sync operation it is necessary to use a planetary program for
executing a goto command to a well known star and, once perfectly centered, for
syncing the mount position to that star. Any planetarium program compatible with
the ASCOM drivers can be used for this operation. Examples of this planetarium
application are the Cart du Ciel (CdC) and Skysafari (that can interact with the
StarGO even using WiFi connection. The examples that follows are performed using
CdC. A more detailed explanation on how to use CdC with Avalon Mount under
ASCOM environment is given in section 3.7
For the correct execution of the Single Star Alignment, the operations must start with the
mount pointing to the North (toward Polaris) and counterweight bar pointing down toward
the ground. This position is usually abbreviated as CWD. For the M-zero and the M-uno
mounts it is the DEC arm that must point toward the ground. Their User Manuals explain
this in detail. Equipping the telescope with a well-aligned finderscope that has a crosshair
reticle eyepiece, will be useful in this procedure, especially if the primary telescope has a
long focal length.
In this position it is assumed that the telescope is pointed toward the North Celestial Pole.
However, due to several potential errors (approximation in finding the exact CWD position,
polar alignment errors, conical errors between the mount and the telescope, etc.), this
assumption may not necessarily be true. To navigate in the sky with true precision, after
obtaining a good polar alignment, it is necessary correct these errors by performing few
syncing operations, described below:
1.
SYNC HOME POSITION
: This operation will inform the system that the telescope is
in the CWD position (with the various uncertainties mentioned above). The operation
starts with the mount just switched on, after the correct site coordinates and date
parameters in the software are verified. Press the "
Sync Home Position
" button in
the StarGO Align Control Panel (see also
). The StarGO coordinates
display will show 90° 00' 00" in DEC. The RA value will correspond to the East
meridian transiting position at the actual time, as the following figure shows.
Figure 3.5.1b: RA/DEC coordinates display
2.
STAR SYNCHRONIZATION:
The second operation is the telescope synchronization
with a star, preferably close to the target object. This action causes the scope to
refine the precision of the pointing and corrects most of the errors mentioned earlier.
To execute the sync, perform a GoTo to a known star in the CDC planetarium
(already connected to the StarGO via ASCOM). To refine the centering, use the
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