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Obsession ServoCat Question

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#1 jragsdale

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Posted 04 July 2020 - 10:54 AM

Hello! I have an Argo Navis DSC with encoders installed on my 20" Obsession already and would like to take the plunge into full GoTo. I checked out the ServoCat page, but there's like a hundred different options with confusing terms like the choice between "Deluxe geared motors", "Std Servo Motors" and "Skewed Armature Lo-Cog Servo motors w/gearbox" without any pictures or description to compare the difference. And there's a $1,000 different between their retro kit and their DIY kit. I definitely consider myself somewhat handy and a little DIY oriented, so if I can avoid paying the full $2k for the Retrofit Kit + ground board I'd prefer to go that route but navigating the options is a little confusing and I don't want to buy something I don't end up needing.


Edited by jragsdale, 04 July 2020 - 10:56 AM.


#2 tjschultz2011

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Posted 04 July 2020 - 11:40 AM

I would recommend emailing or calling Gary Meyers, the owner of the company, and asking him to walk you through what you will need. He's excellent to work with and helped me retrofit a gen 1 ServoCAT setup (that I purchased here in the classifieds, not even from him) on my 17.5" dob. Gary was extremely helpful in walking me through what I would need to do and buy to make the setup work and I'm happy to report that it's working excellent and I've even started doing some imaging with it (see my signature), which surprised Gary quite a bit, considering dobs can't usually track well enough for DSO imaging. I would highly recommend their stuff and I will definitely be buying from them in the future. 

 

TJ 


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#3 jragsdale

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Posted 04 July 2020 - 12:08 PM

Yeah, that seems best, but I'm always nervous to ask "the salesman" what I really need, because they always say you need everything, and the best options. :)



#4 tjschultz2011

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Posted 04 July 2020 - 12:24 PM

I wouldn't worry about that too much with Gary. He casually mentioned a few different routes I could go, some of which did involve buying some expensive things from him, but I wouldn't say he pushed those options or made me feel like that was the way I had to go. He was always very willing to help me make my current gear work, which required some DIY work on my scope and a software upgrade. He was even able to provide the former generation manual that went with my system and also the newer generation manual which had some applicable info in it after doing the software upgrade along with detailed instructions on how to do the upgrade. There were a few cables and adapters that I didn't have and I was happy to buy those from him since he helped me so much with the retrofit.  


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#5 a__l

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Posted 04 July 2020 - 10:47 PM

$1,699 15-20”

15” - 22”: $259. ($35 S&H) If you do not have a good round GB

$129 Powered Ground Board If you want to take the battery out of the rocker or $179 Complete kit.

$219 If you want a wifi remote

 

Obsession 20" heavy telescope. The main problem is making it rotate easily along the az axis.

There is another problem when sharing 12V motors and ArgoNavis.
Ferrite rings on cables for Argo encoders are needed.
Or only use AA batteries for Argo.


Edited by a__l, 04 July 2020 - 10:58 PM.

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#6 jragsdale

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Posted 05 July 2020 - 12:38 AM

Great info, thank you!



#7 tmiddendorf

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Posted 16 July 2020 - 08:41 AM

a__l you mentioned using ferrite rings for Argo encoders. Are you using Argo supplied encoders or are ferrite rings needed on any encoders when used with the Argo-Navis? How did you discover the need for these? Do you locate the rings at the encoders, at the Argo-Navis, or both?

Thanks


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#8 Jeff Morgan

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Posted 16 July 2020 - 12:31 PM

I wouldn't worry about that too much with Gary. He casually mentioned a few different routes I could go, some of which did involve buying some expensive things from him, but I wouldn't say he pushed those options or made me feel like that was the way I had to go. He was always very willing to help me make my current gear work, which required some DIY work on my scope and a software upgrade. He was even able to provide the former generation manual that went with my system and also the newer generation manual which had some applicable info in it after doing the software upgrade along with detailed instructions on how to do the upgrade. There were a few cables and adapters that I didn't have and I was happy to buy those from him since he helped me so much with the retrofit.  

 

Gary is definitely a Technical Guy, not a Sales Guy.



#9 a__l

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Posted 16 July 2020 - 04:50 PM

a__l you mentioned using ferrite rings for Argo encoders. Are you using Argo supplied encoders or are ferrite rings needed on any encoders when used with the Argo-Navis? How did you discover the need for these? Do you locate the rings at the encoders, at the Argo-Navis, or both?

Thanks

This is not my method. This is a common filtering method.
The encoders I use are US Digital 10K. From the physics of the process, noise filtering is possible with a smaller number, with a larger number, problems are possible (it is necessary to study the noise).
Found it when I got incomprehensible pointing errors when trying to use the TPAS algorithm on my 24" telescope.
The error test can be performed during the day in a confined space, using the Alt axis up and down, using a motor and limiting the feed in a vertical position (for example, with a rocker wall). For example 10 attempts. The error will be in the form of adding encoder digits. More likely at maximum motor speed. Rings are used on every wire encoder near ArgoNavis.

Gary (ArgoNavis) suggested that I use these rings for the ServoCat wires motors, but it didn't help.

 

I haven't tested it, but chances are it will be on the Nexus DSC too. Advantage, this DSC has a lithium battery and you can do without sharing 12V.

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Edited by a__l, 16 July 2020 - 05:16 PM.


#10 a__l

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Posted 16 July 2020 - 06:34 PM

There is a contradiction. Number of encoder ticks and noise frequency (from motors). At some frequency, it may become the same. Therefore, in the general case, filtration for encoders cannot solve the problem. For any device Nexus-II, Nexus DSC, Sky Commander, ArgoNavis, etc. Only reduce the noise from the motors. 12 volts from different batteries, one of the methods.

 

Older devices may not support high encoder frequencies, for them the problem is easier to solve.


Edited by a__l, 16 July 2020 - 06:57 PM.



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