4 replies to this topic

[marvyyk]

Hi CN!

 

I tested various balancing approaches for my CEM26 to see if there's one that significantly improve guiding...

 

I tried various approaches including to be well balanced on each axis... But I can't say that it is any better on guiding than a bit camera/CW heavy... So, I'm inconclusive!! Help 

So I tought I would ask the owners to share there experiences!! 

 

Thanks in advance and Clear sky! 

 

Marc

[pyrasanth]

I think the slightly off balance in one axis to improve guiding is perhaps outdated. Mounts now have so much precision that a precise balance everywhere is the way to go.  I think you only appreciate a good balance when your mount is expected to move in a contorted position for a human & it fails- that tells you the importance of a good balance. Just as important is polar alignment- that can also have a very significant difference to the quality of your overall image quality. Get a good balance & polar alignment and you will be well on your way to good image quality being captured. I would not stress too much about the perfect feather balance in any position- nice if you can get it however close may be good enough.

Edited by pyrasanth, 17 September 2024 - 07:00 PM.

[Pgblack]

I have a CEM25P and like the above poster, I try to get as good a balance as can be achieved without being overly obsessive, I don't do any third axis balancing. Because these CEM mounts are so free moving when unlocked, even the smallest imbalance is easily noticed, for example the offset weight of an EAF, in reality I haven't noticed this having any negative affect on guiding performance. I have been imaging for the last couple of hours and my rig is guiding in the 0.5 - 0.65 arc sec rms range (APM 80ed triplet with IMX571 camera, 50mm guide scope etc) which is typical in average to good seeing, poor seeing results in 0.8 to 1.2" rms

[pyrasanth]

I have a CEM25P and like the above poster, I try to get as good a balance as can be achieved without being overly obsessive, I don't do any third axis balancing. Because these CEM mounts are so free moving when unlocked, even the smallest imbalance is easily noticed, for example the offset weight of an EAF, in reality I haven't noticed this having any negative affect on guiding performance. I have been imaging for the last couple of hours and my rig is guiding in the 0.5 - 0.65 arc sec rms range (APM 80ed triplet with IMX571 camera, 50mm guide scope etc) which is typical in average to good seeing, poor seeing results in 0.8 to 1.2" rms

I agree entirely with your post. I'm currently imaging with my CEM120 that has a RASA 11 and an Altair ETX115 APO on the mount with all the associated filter wheels & cameras. There is no way I can say it is fully balanced in all positions but like you I get fairly good guiding when conditions allow under my Bortle 7 skies. I've posted my PHD2 guide graph from tonight which is typical.

 

[marvyyk]

Thanks to all for your feedbacks and those shared experiences! It's intersting to read you!!

 

My guiding when seeing is good is around 0.85 arc sec rms and around 1.1" when poor.... My sky quality (or bad quality) might also contributes! Bortle 9ish...

 

I have a comparable setup as @Pgblack, in  my case a Zenithstar 73 with IMX571 camera, 50mm guide scope etc.