Index

Sync

The sync features improves pointing accuracy in a small region of the sky about 5 degree by 5 degree to very high precision. On the other hand, alignment improves pointing accuracy over the entire sky, but to a lower precision. Sync is useful for you to record the pointing error of a brighter object so that subsequent GOTO to a fainter object nearby is more accurate.

Sync should be done after alignment. This is because sync is meant to correct the residual error of alignment.

Like pointing model, sync data is stored in each individual app instance. Sync data is restored when app reconnects to the same mount. When pointing model changes, sync data will be automatically reset.

Performing Normal Sync

After you perform GOTO to any object, the object may not be exactly centered in the field of view. Therefore after a GOTO the app will prompt you to use the direction buttons to make the object fully centered. This centering procedure is sync. An eyepiece with an illuminated reticle can help you do this accurately. Before you can confirm center, the last slewing buttons you press must be the RIGHT and UP buttons. The right and up buttons will blink to remind you of this.

A third party planetarium app tethered to SynScan app can also cause sync to be performed. To do that you first slew and center an object in the field of view. Then in the planetarium app, select the sync function while specifying that object. This causes planetarium app to request SynScan app to perform a sync.

Align With Sync

Under normal circumstances when a planetarium app requests SynScan app to perform a sync, SynScan app would do as requested. However, if in SynScan app the Alignment > Align with Sync menu is opened when the sync request is received, SynScan app would act as if an alignment star has been centered. This would allow you to use the planetarium app’s catalog to perform alignment.

Re-purposing the sync request is necessary because the communication interface between SynScan app and planetarium app lacks a separate “alignment” request.

The Align with Sync page shows the last three objects you aligned to. You can delete the last aligned object to undo the last alignment step.

Choosing Alignment Star

Since when performing align with sync, SynScan app does not help you choose which alignment stars to use, you must take care to follow the alignment star choosing rules: