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EQDrive and other options

eq ATM equipment mount
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6 replies to this topic

#1 Space99

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Posted 21 November 2017 - 03:54 AM

Hi everyone,

 

I'd like to start a discussion re drive options of a EQ mount.... new or old....  I hope this is OK by the mods...   smile.gif

 

Noticed Valentine's add  https://www.cloudyni...-40kg-and-more/

 

I'd do like this kit... I'm in the design stage of a big EQ mount ( in a  permanent observatory.)

 

I think it would be beneficial for all of us if we get all the info/education what we can get about this and alternative systems.

The original EQMOD is 'stuck' with the 705:1 gear ratio .... this 'interface' is free from that, and it does not use a 'micro-step'  ...  drive the stepper as a 'synchronous' motor.... direct drive the worm without 'jitter'   ??

 

Also, options for us on a budget, is a 2nd hand Gemini 1,  AstroEQ  https://www.astroeq....k/tutorials.php   and Synta's EQ6 go-to upgrade kit with steppers (stuck with overall gear 705:1)

 

Not sure how this will compare to a servo based system, like Sidereal Technology Servo Control. I'm on a budget, so it's about 1:2 cost difference...  can't use EQMOD and a servo motor is way more expensive.

And noisier (with the transfer gears)!

 

If you are using any of these system, I'd like to hear your opinion.

 

ps: I'm interested in buying one of the systems, and have no financial or personal interest in any of the vendors.

 

Kind Regards to all,

Mick


Edited by Space99, 21 November 2017 - 04:06 AM.


#2 orlyandico

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Posted 21 November 2017 - 05:15 AM

I can't speak to EQDrive, but I bought a Littlefoot Elegance Photo (LFEP) for over $700 a few years ago.  It was one of the best stand-alone GoTo controllers back then for stepper motors and I thought I got a good deal.

 

Bad move. The guy designing them (Rajiva) decided to close shop and now I have a boat anchor.

 

For this reason, I would highly suggest something like OnStep which is open-source, so even if Howard stops working on it, the source code is out there and people can continue developing it.


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#3 burdij

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Posted 21 November 2017 - 03:13 PM

Could you use AstroEQ. It is usable with any size steppers, just depending on which drivers you use and allows a number of drive gear ratios to be accommodated. It does use microstepping to achieve a compromise between fine control and fast slewing. ASCOM is supported.

 

Here is the link: https://www.astroeq.co.uk

 

I have built a version of this for an EQ-5 mount which integrated well with Stellarium and Cartes du Ciel. Haven't tested the SGP yet, though.


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#4 benula

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Posted 21 November 2017 - 04:34 PM

Here's another vote for OnStep.



#5 astrokor

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Posted 22 November 2017 - 02:56 AM

I am the founder of the EQDrive project.
In the beginning the project was like the others, based on the motor drivers STEP/DIR.

 

The study showed that such control is not softstart and not flexible. And we developed a control algorithm similar to synchronous motors. We got control over the parameters of the stepping motor without a closed loop.

Currently the project, is not open sources, but is now available as DIY.
http://www.eqdrive.com.ua/?page_id=969
Sorry so far only Russian language. :(

 

In the near future I plan to open the source of the project.

 

Best regards,
Ruslan Korop.


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#6 Space99

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Posted 22 November 2017 - 03:13 AM

I am the founder of the EQDrive project.
In the beginning the project was like the others, based on the motor drivers STEP/DIR.

 

The study showed that such control is not softstart and not flexible. And we developed a control algorithm similar to synchronous motors. We got control over the parameters of the stepping motor without a closed loop.

Currently the project, is not open sources, but is now available as DIY.
http://www.eqdrive.com.ua/?page_id=969
Sorry so far only Russian language. frown.gif

 

In the near future I plan to open the source of the project.

 

Best regards,
Ruslan Korop.

Thanks Ruslan,

and welcome to CN :) 

 

Glad you join in and explain how it works.

 

In your opinion open loop, like the stepper driver you have with EQMOD, how would it compare to a servo based software like Sitech or Gemini?

 

I do like the stepper for the reason of low transfer gearing... less noise and backlash. The simplicity of the electronics is a bonus too. However, it's an open loop and you drive it like a 'synchronous' motor ... so how is the pointing accuracy compare to the servo based systems?

 

Thanks,

Mick


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#7 astrokor

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Posted 22 November 2017 - 03:52 AM

Sitech is a good integrated development. It supports many configurable parameters. I am guided by this development.

 

Yes, the stepping motor and the synchronous motor mode were chosen as an alternative to the servo motor.

 

Of course, an open loop does not give absolute accuracy. The next step is a closed loop with stepper motors and encoders. But, the EQDrive system gives a smooth move in comparison with the microstep mode and guiding solves the problem of an open loop.

 

Ruslan




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