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NINA : Guiding error

Sky-Watcher EQ6-R Pro ZWO ASI120MM Mini ZWO ASI533MC Pro Acquisition Deep Sky
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Dimitris Kavallieratos avatar
Dimitris Kavallieratos avatar
Hello everyone,

When guiding with NINA with my EQ6R ,I always see the following error after dithering completes resulting in producing star trails in several frames :



My guide scope is the ZWO 120 mini and my guide camera is the ZWO ASI120MM mini, I image with my ASI533MC pro and my NINA guiding setting are :



What's the issue here, I am wasting imaging time and throw out many frames because of this...

Thanks in advance!
andrea tasselli avatar
andrea tasselli avatar
Dimitris,

Have you tried with PHD2 alone?
Dimitris Kavallieratos avatar
Dimitris Kavallieratos avatar
andrea tasselli:
Dimitris,

Have you tried with PHD2 alone?

Without an acquisition software you mean?? In PHD2 and error appears that says that could not correct in RA in time as a warning...



What do you mean Andrea with PHD2 alone?? Can I dither without the acquisition program doing the dithering as part of the sequence??

When I am just guiding everything works perfectly, also I did not mention that I guide directly through the mount with an EQ dir cable...
andrea tasselli avatar
andrea tasselli avatar
Well, I guess you answered my question. Without dithering PHD2 guides well so the guiding parameters are ok. I guess your mount has enough dec backlash to need further time than given to settle down. Try doubling the settling time. Or avoid dithering altogether. I never dither, I just let the mount drift do the thing for me.
Concise
Marc-Antonio Fischer avatar
Marc-Antonio Fischer avatar
Dithering is very imprtant! Pls still dither. How long is your PHD2 Loop? 2 secs? I  see your guide graph here after dithering. How long does it take to be normal? you set 90 secs. (thats why to long btw) settling is 10 secs for my eq6 r pro
andrea tasselli:
Well, I guess you answered my question. Without dithering PHD2 guides well so the guiding parameters are ok. I guess your mount has enough dec backlash to need further time than given to settle down. Try doubling the settling time. Or avoid dithering altogether. I never dither, I just let the mount drift do the thing for me.
AstroDarkSky avatar
AstroDarkSky avatar
Using the PHD2 log viewer may help seeing the time sequence when the dither starts and how long it is trying to settle before it gave up and timed out.

https://openphdguiding.org/phd2-log-viewer/

As @Marc Fischer said, 90 seconds is extremely long and basically once it gets past approx the 30 second mark, it probably isn't going to complete and you just end up wasting time trying to settle at an unattainable goal and no amount of time will probably work.

Maybe try taking a look at the logs with that utility and see if you see any dithers completing. My bet is you may have some smaller dither amounts complete while the large dithers (size of dither is randomly selected by default) are causing the fails. If so, then the mount just cant settle to that level of precision probably due to backlash.

Another thing to double check is the true focal length setting used for your guide camera. But I'm less confident that is your problem, but always something that can go wrong for a lot of us when changing rigs

The default NINA suggestions should complete dithers relatively quickly without any changes - like in the order of 1-4 seconds for the majority of rigs. (at least ones I own)

I didn't see if you had run the Guiding Assistant in PHD2 or not, but it can help with a realistic estimate of your backlash and you can apply all of its recommendations and it might solve your problem.

Just some ideas! Good luck!
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andrea tasselli avatar
andrea tasselli avatar
Marc Fischer:
Dithering is very imprtant!

If you use a DSLR, especially if a Canon (or Fuji), then yes it is very important. Otherwise not really. I never dither intentionally.
Dimitris Kavallieratos avatar
Dimitris Kavallieratos avatar
Well...By increasing the settle time to 120secs I managed to only fail in some of the dither's settles and not in all of them...Still as mentioned too much wasted time.

@andrea tasselli Can dithering be skipped even for my B8 backyard? If so that would be great...

Thanks for the answers guys! I will try the PHD2 guiding assistant as suggested and post back my solution, hoping that there is one   At least for now only 3-4 frames out of ~60 are wasted with the increased settle time...
andrea tasselli avatar
andrea tasselli avatar
Can dithering be skipped even for my B8 backyard? If so that would be great...


LP has nothing to do with the need to dither or otherwise. So far I haven't seen any indication of walking noise from anything other the old Canon I have.
Dimitris Kavallieratos avatar
Dimitris Kavallieratos avatar
andrea tasselli:
Can dithering be skipped even for my B8 backyard? If so that would be great...


LP has nothing to do with the need to dither or otherwise. So far I haven't seen any indication of walking noise from anything other the old Canon I have.


I thought that LP amplifies the random noise and dithering takes care of that… This and noise pattern of your sensor. 

Anyway thanks for your input again ,will experiment without dithering for sure! At least for a session.