S50/S30 platesolving for recentering while capturing in Stargazing

gofraro

As we all know, the tracking accuracy of the S30/S30 is not comparable to the AM3/5, and paired with the effects of field rotation and dithering, this can lead to a significant number of rejected frames during the course of a session. Not only in standard mode but also in framing mode.
One easy solution to improve the capturing and eventually the stacking is to do a platesolve and recentering in certain intervals to mitigate the risk of loosing track and reference stars. The time that is needed for this purpose is negligible compared to the number of dropped frames.
Thanks a lot in advance for your attention

Tech@ZWO

gofraro Thank you for your suggestion, It has this function already.

gofraro

Tech@ZWO
Thanks for your response. Maybe, the function is already included, but it doesn't work.
Did a cross-check with my gathered data. Stargazing-Livestack, individual fits. After the fifth frame, you can see a change in the recorded RA/Dec coordinates in the fits-header. Then, this value is kept constantly until end of capture (no matter of 100 or 600 frames). However, you can clearly see the dithering and shift/drift over the whole sequence. Conclusion, if they do a platesolve, this happens only once (after or around the fifth frame), or, they do not record it in the subsequent files. And I cannot see any re-centering. Therefore, stars close to the edges move off the frame and get lost for identification as reference stars, likely leading to a "stacked failed".
Please take closer look on it. If necessary I can provide more data.
I checked with my gathered data from February until December. Therefore, it is not related to any update or firmware release.
I'm pretty sure and confident, that a proper and periodically platesolve and re-centering can significantly improve the Stargazing experience.

Tech@ZWO

gofraro Could you share some pics here, i will forward and confirm it, thank you.

gofraro

Example of M81 from 29.11.2024, frames 1/6/16/366
RA/DEC info from fits-header
Comparing the images you can see, that the center of the image (M81) has moved over time but the RA/DEC still remain the same,

Btw. yesterday I let Sharpcap stack this sequence in its livestack (using the folder monitor cam) and did watch the movements. It scares me that dithering is making such huge steps (jumps). Normal image deviation is 1 or 2 px whereas during dither the frame-to-frame-offset is more than 30px sometimes over 100px.
Such big moves takes time and sufficient settlement. If reference stars move outside the frame or you get startrails, it is no wonder why sometimes a huge amount of frames are getting rejected. Please, can you take also a look on that ? Thx.