Question Poor guiding results - M-Zero

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18 Jun 2024 04:26 #1307 by Astroboy
Poor guiding results - M-Zero was created by Astroboy
Hi,

When I first got my M-Zero running, my guiding would average 0.38"~0.48" total RMS (PHD2), however for the past few months, the best I can manage is 0.8" total RMS and sometimes as bad as 1.1"~1.15" total RMS.

The only change to my whole setup has been the addition of a focal reducer, however my guiding went bad before the focal reducer was added.

The setup is:
M-Zero EQ
Askar 65PHQ (with and without the 0.75x reducer)
Player One IMX294 camera with OAG
Imaging with NINA, Guiding with ASI120MM mini and PHD2.

Ra & Dec guide rates are 0.35x
Max Movement for RA and Dec is 800
Min Movement for RA and Dec is 0
RA and Dec aggression is 90%
Algorithm is Lowpass 2 for both RA and Dec.
Guide Exposures are between 1s and 1.5s (I use longer exposures in poor seeing to reduce high frequency star movement) 
Calibrations seem OK, but guiding is all over the place.

RA is decidedly worse than DEC (RA is usually 0.8" RMS or worse, dec is 0.5" ~0.6" RMS)

I can supply guide logs from both earlier guiding sessions where results were 0.4" RMS and from last night where it was as bad as 1.5"
Any suggestions? 

Alex
 

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18 Jun 2024 04:33 #1308 by Astroboy
Replied by Astroboy on topic Poor guiding results - M-Zero
Oh, its worth mentioning, the guider resolution is 2.3" per pixel, the main imaging camera is 3.05" per pixel, so my images are still coming out quite reasonable... but I can't understand why the guiding went from 0.3~0.4" to 0.8~1.15"

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21 Jun 2024 13:27 #1309 by Stefano82
Replied by Stefano82 on topic Poor guiding results - M-Zero
Hello

In order to help yu better understand what may have be changed, please provide some logfiles and more details on the setup (imaging scope and guide scope focal length, telescope and accessories dimensions and weight).

Is the balancing reasonably fine?

Best regards

 

Stefano
Avalon Instruments Team

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06 Jul 2024 11:04 #1316 by Astroboy
Replied by Astroboy on topic Poor guiding results - M-Zero
Hi Stefano.

Imaging Scope : Askar 65PHQ with and without the 0.75x reducer (312mm - 416mm focal length)
Guider setup : OAG with ZWO ASI120MM mini camera (2.48" per pixel)

I uploaded 4 log files to google drive:
19 April 2024 - Great guiding, no focal reducer.
2 June 2024 - Average/poor guiding, no focal reducer.
13 June 2024 - Average/poor guiding, no focal reducer. (I changed some settings to try to aleviate the issues, but with little to no improvement at all)
17 June 2024 - Average guiding, focal reducer fitted (I changed more settings, again, no decent improvement in guiding)

Log Files are here : drive.google.com/drive/folders/1IX_XOzTL...aGmo5?usp=drive_link

Balance is quite good... There is a slight imbalance in the system because the ZWO EAF weighs 300g and hangs off the left and side of the scope, so there is a minor 3rd axis imbalance that I'm working on resolving, however that existed in the first log file where guiding was 0.5" RMS or better, so I don't think that is the problem. Dec is balanced quite well otherwise, and RA is as close as I can get it to being EXACTLY balanced, but it is hard to tell exactly because one side of the scope is heavier than the other. Again - this is unchanged from the first log file where guiding was good.

Thanks for any assistance you can provide. 

Regards
Alex.

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06 Jul 2024 11:32 #1317 by Astroboy
Replied by Astroboy on topic Poor guiding results - M-Zero
Oh, Telescope dimensions,

The scope is 63cm long from the front of the dew shield to the back of the camera, the width overall is thinner than the M-Zero Declination arm, but the ZWO EAF hangs out the left hand size by 4.4cm and weighs 377g.

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09 Jul 2024 15:12 #1319 by Stefano82
Replied by Stefano82 on topic Poor guiding results - M-Zero
Hi Alex

Thanks for the log file provided, we made a check on them and we saw that the settings are almost all ok, calibration seems to be good as well, so maybe with some adjustment it will be possible to improve the performance.

From what we saw, in the first log you set the Minimum move to 0 while in the next sessions you increased that value. We suggest to set to 0 and see if what happen.

Moreover, from the log file we see the Guide Speed in a-s/s value, can you please let us know which speed do you set in the StarGo.exe?

In order to improve the balancing, even though it seems to be ok, you can try to reduce the overall setup dimension putting some device in the bottom side of the mount, taking advantage of the M-zero Dual Dec feature. This will help you keep compact your setup and reduce flexure.

Try in this way and let us know about.

Stefano
Avalon Instruments Team

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