The Utility > Advanced menu is available only in SynScan Pro App.
Polar alignment is the process of aligning the RA axis of an equatorial mount along Earth’s axis of rotation. Accurate polar alignment improves equatorial mount’s tracking accuracy. The polar alignment obtained from roughly putting the equatorial mount in [home position] is often good enough for visual observation. Higher accuracy polar alignment is needed for astrophotography.
Polar alignment involves making fine adjustment to the equatorial mount’s altitude and azimuth orientation. Consult reference material for your mount for how to do that.
You can see the amount of polar alignment error (Tilt) in Utility > Information once you have performed an alignment involving at least two stars. You can use this to decide whether you need to perform accurate polar alignment.
Utility > Advanced > Polar Scope helps you use the polar scope to polar align an equatorial mount. This page shows where Polaris or Octans should be aligned in the reticle of the polar scope.
You can also adjust the brightness of polar scope reticle light. This is only applicable for mounts that have this hardware.
Utility > Advanced > Polar Alignment is for polar aligning an equatorial mount without using a polar scope. To use this feature you must have performed an alignment involving exactly two stars which have similar declination values. 3-Star alignment is NOT recommended for polar alignment.
When the routine starts you will be prompted to choose a star. Use one of the stars that you used for alignment for best result. Then follow the prompts to adjust the mount’s altitude and azimuth orientation.
Auto Home (Utility > Advanced > Auto Home) is an automated process that recovers axis position origin to axis home index position. Axis position origin is an element required to keep previously performed alignment valid, as described in [Preserving Pointing Accuracy].
Auto home also has the effect of turning the two axes to a specific position relative to the chassis. The axes will be turned such that, if the chassis was upright and polar aligned to north celestial pole, then:
PPEC a feature where mount compensate for its periodic error. Periodic error refers to the small, time-varying deviation in physical axis speed from the ideal axis speed. Periodic error is due to imperfection in the gear system. The magnitude of this error is small enough to not impact visual observation, and is only of concern to tracking during long exposure astrophotography. Since typically only equatorial mount is used for astrophotography, PPEC is not relevant to alt-azimuth mounts. Not all equatorial mounts support PPEC.
The extent that periodic error can be corrected by PPEC is limited. Like autoguiding, PPEC is a way to improve astrophotography performance of a mount. Compared to autoguiding, PPEC requires less setup (after a one-time training process). Autoguiding on the other hand, can compensate for more sources of error.
How PPEC works is that PPEC training records periodic error compensation data, then PPEC playback uses the data to compensate for periodic error. Compensation data is stored in the mount. Meaning that once training had been done, any instance of SynScan app that connects to the mount can perform playback. Compensation data stays valid until you make mechanical changes to the RA axis gear system.
Ensure you have accurate [Polar Alignment] before starting PPEC training and playback, as it is something also required for accurate equatorial tracking.
The time it takes for PPEC training to complete or for PPEC playback to become stable depend on the periodic error cycle length. It varies depending on the mount model, and is typically about 10 minutes.
To start PPEC training, perform polar alignment, and set up autoguider to track a star near the celestial equator and away from the horizon. While the mount is tracking the star steadily, go to Utility > Advanced > PPEC and choose Start. Mount will start to record compensation data, and report completion after some time. Training time can take up to twice the mount’s periodic error cycle length.
It is also possible to perform training without an autoguider. You can do that by keeping the star centered in the field of view using the slew direction buttons.
Turn on PPEC playback in Utility > Tracking. It can take up to one periodic error cycle for playback to become stable.
You can use the app to control a camera to take a series of photos of varying exposure time. You can also use the app as a remote to manually open and close the camera shutter. The camera control features in this app is intended for astrophotography. For a much richer set of ground photography tasks including timelapse and panorama, use the SynScan Photo Android/iOS app.
Setup for camera control requires you to attach an adapter cable from the SNAP port on the mount to the shutter release port on the camera. Your vendor may have compatible cables for shutter release ports on Canon, Nikon and Sony cameras. The exposure time setting on the camera should be set to BULB to allow control of both the timing and length of exposure from its shutter release port.
The Timer page in Utility > Advanced > Camera Control can be used to specify a list of items called exposure groups. Each exposure group represent a number of photos to take with the same exposure time. You can add items to and modify the list, and let the app run it.
In each exposure group you can also specify pause time between each photos. It is useful for waiting for the camera sensor to cool.
To keep camera timer running you need take measures as detailed in [Maintaining Long Running Task].
The Bulb page in Utility > Advanced > Camera Control is for manually controlling the camera shutter. Press and hold the Bulb Shutter button to open the shutter. Release the button to close the shutter.
In Utility > Advanced > Diagnostic > Response Time you can see the statistics of communication between the app and the mount. You can use measured response time to adjust [Communication Parameters].