Recentering target during a session

Is there anyway during an imaging session to automatically re-do a plate solve to ensure your target stays in the field of view. It would be ideal if SGP could run a plate solve after a set period of time to ensure the targets stays in the center of the camera field of view. A rival automation package has this ability however it is not integrated into SKG so I can’t use that program.

I’m currently working out the settings in SGK (SkyGuard) however because the guiding frame is sometimes lost Skyguard aquires a new guide frame from the current mount position and thus the target drifts which can mean a lot of data going in the bin.

Any advice appreciated- Thanks.

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OOPS mu bad sorry but this was meant for a post on Stargazers Lounge

I will also like to know how to force a platesolve after a set period of time.

I have a brute forces way of re-platesolving once an hour (or any other time period).

Let’s just say I am imaging M57. I platesolve for M57 and create an M57 ‘target’. I then fill out the event information (exposure, binning, repeat etc). If I want to re-platesolve once an hour, I select something like 2 minute exposures and set repeat to 30. Then I simply duplicate the target several times (you can do this by ‘right clicking’ on the M57 target and selecting ‘duplicate’.

That creates several events all with the same settings. When SGP completes an event it will move to the next and perform a new platesolve. You can also have SGP refocus, etc since this is a new event.

This may be a little clunky, but it works. I have a dual telescope mount so I do get a little bit of shifting as time goes by . Re-platesolving re-centers the object.

Maybe someone else has a better way of doing this.

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I did think of this method earlier on before I posted & it certainly would work, however I think it should be implemented as a feature. Voyager has this feature as it is much more useful for unguided imaging where the target would drift

I agree.

I use this technique but it would be easier if I could simply set platesolve to run on an interval.


We have a general aversion to adding functionality to address symptoms of other issues. Maybe we don’t fully understand the request, but this doesn’t seem like a thing that should be required. At the same time, it seems to be a fairly popular request. I read through several notes on how to make this happen, but I didn’t see anything that explained why functionality like this would be required. Please don’t interpret this a challenge to the request… just trying to understand if the root of this request is actually somewhere else and needs to be addressed upstream of periodic recentering. Is it that your rigs are not permanent and achieving reasonably perfect polar alignment is difficult? Is it a guiding issue? flexure? Maybe mirror shift? Can you explain what series of events leads to the need for this? If we can get a better understanding of needs here, it will help in terms of prioritizing feature requests against one another.

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Hi Ken,

Thank you for your reply. Not everybody has a perfect polar alignment as you know.

If you want to be able to image in the field but not guide with a less than perfect polar alignment then over a period of a short time your target will drift in the subs necessitating cropping or lost frames. There are times where guiding may not yield the results you expect and need to just rely on the mount to do its thing as accurately as the alignment allows.

What happens if you were in the field & your guiding equipment failed?- you would have to keep implementing short and duplicated sessions to keep your target in the field of view. This could easily be addressed with a simple timer that could do an realign after a timed interval or frame count. I can think of many scenarios where this could be useful.

This feature is implemented in Voyager so its hardly a show stopper for me however I see it as a bit more important than a nice to have if I want to do an unguided imaging session as I would need to rely on an accurate polar alignment which may not always be as precise as needed for unattended no guiding- please give the feature at least a consideration.

I have recently been wanting this functionality. For me, it doesn’t stem from polar alignment. When guiding, particularly at long focal lengths with the target filling more than 50% of the frame, the dithering process eventually walks the target toward one edge, effecting the final framing. If it could recenter a couple times throughout the session, that would fix the issue.