SmartTrackACP Utility

This addon utility for ACP uses the pointing model generated for your mount to enhance its tracking accuracy as well as its pointing accuracy, allowing longer unguided exposures to be achieved, useful for imaging in the field where setting up an extra guide scope is troublesome.

SmartTrackACP will automatically compensate for all of the error parameters modeled by the pointing engine in ACP, including polar misalignment, RA/Dec bias, axes misalignment and tube/mount flexure. It will also correct for the changing atmospheric refraction if you have enabled that in ACP.

It does this by constantly monitoring the difference between the physical coordinates of the mount and the corrected coordinates those physical coordinates would map to once the mount model correction has been applied.
If the difference goes over the specified allowable error, ASCOM pulseguide() commands are sent to the mount to correct it’s pointing.

An example of the level of correction achievable is shown below. This is an animation of a pair of 400 second (6.7 minute) test shots through my 10" LX200R SCT, one regular unguided shot, the other also unguided but using SmartTrackACP.
The scope has a focal length of 2760mm, giving an image scale of 0.67 arcsec/pixel. The trailing is evident in the unguided image, but greatly reduced by running SmartTrack.

SmartTrack animation

Usage:

The SmartTrackACP utility relies on the ACP pointing model being accurate enough to calculate small errors in the mount pointing. In order for this to be true, you need to ensure it has enough measurement points on each side of the meridian you will be tracking. I would recommend having at least 30 points on each side of the meridian, or more if your mount has a large pointing error.
This is easily achieved by using the auto-mapping script in ACP.

Once a sufficiently accurate mount model has been built up, simply slew to your desired target, set the desired maximum allowable error in arcsecs and click the “Start SmartTracking” button.
This will change the status line from “Normal Sidereal tracking” to “SmartTrack Tracking” and the current deviation from ideal tracking in RA/DEC will be displayed.
Whenever these errors go above the configured allowable error, a pointing adjustment will be sent to the mount to reduce the error.
To stop the SmartTrack corrections, simply click the button again and the mount will revert to normal Sidereal tracking.

If SmartTrackACP detects the mount is slewing, it will suspend making corrections until the slew completes, after which it will update its internal target coordinates where it will keep the mount pointing.
SmartTrackACP will also suspend making corrections if it detects that mount tracking is disabled, as happens between plans.
This means you can start SmartTrackACP at the start of your imaging session and leave it running while you image and slew, with no manual intervention required.

Other Development:

I have also implemented this to use the MaxPoint pointing correction engine available from Diffraction Ltd. The MaxPoint version of SmartTrack is available for download here.
 

Config options:

         Maximum allowable error in RA/DEC.

Version history:
v1.0 - Initial release.

SmartTrackACP v1.0


Regards,
John

 

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