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michaelmorris

Which stepper motor-based focusing system?

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For a while now, I've been umming and arghing about replacing the DC motor-based focus controller on my SW 80ED scope.  It keeps losing power and, because it is not a stepper motor-based system, autofocusing routines (such as that offered on SGP) are not open to me.  My umming and arghing has mainly consisted of slowly putting together the bits and bobs I would need to construct my own system based on a NEMA 17 PG motor controlled by Peter Brown's myFocuserPro2 Ardunio-based controller.

https://sourceforge.net/projects/arduinoascomfocuserpro2diy/

This evening I've finally got around to looking at the instructions in great details and I've had to be honest with myself and say that this DIY project is just way beyond my skill set. 

So I've decided to bite the bullet and buy a ready-made system.  But which one?  At present the most promising system seem to be a system by Pegasus Astro

https://www.altairastro.com/Pegasus-USB-Dual-Motor-Focus-Steppers-DC-Servo.html

This would have the advantage of also allowing for also controlling the Meade Zero image focuser on the back of my C9.25..  By my reckoning this would set me back £305.  However, it is not ideal as it means having two bits of kit on the scope (more clutter).  

What are people's experiences with the Pegasus Astro system?

What are the comparably-priced alternatives?

Thanks

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I'm happy with my Dyeepskydad autofocuser; it has been faultless so far (had it for about 6 weeks). It is Arduino based, but so much cheaper than all the alternatives. 

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Pegasus Astro kit....all the way....it’s superb :)

I have two of there motor focusers and controllers, and never let me down, also the support is really good, not that you will need it..

Edited by LightBucket
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I've got the Pegasus Focuscube. It's an all in one system which works well with Maxim DL5. I also have Lakeside Astro ones on the other scopes which work well but I don't use the included controller as I have Hitecastro Astro MHPs which include a focus controller on each. I don't like extra controllers mounted on my kit!

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No issues at all with the Pegasus kit.  The early ones like mine had awful brackets which flexed all over the place, but it looks like they have addressed that with new universal brackets.  Some people don't like the plastic case, and it does make it feel a little cheap compared to, say, a Sharpsky, but it is functional and protects all the innards.

Lakeside is very good, but basic, and the controller is pretty big.  Like others, I use mine without the controller via a Pegasus hub, but if you don't have one of these then the controller can be a mission to house.  Big benefit of Lakeside is the custom bracket and coupler they make for your focuser, which means the fit is perfect.

SestoSenso is very good.  Problems noted for me is the weight (it's actually fairly weighty as it's all aluminium) which has resulted in me needing additional lateral balancing at the front of my dovetail to counter it.  Also the red flashing LED is quite bright and is difficult to mask as the cover is translucent.  It can't be dimmed or switched off, which I think is an issue, and this won't be changed as the hardware doesn't let them do it (this was info from Filippo at PLL).  Finally, it fits on the micro-focuser shaft which, as most are ball bearing reduction, can lead to some slippage over time.  However, I've not found this to be an issue to date.  Plus side of this means the resolution is incredible.  For control, including speeds, torque, acceleration rates etc. the SestoSenso blows everything else out of the water.

Not used the Sharpsky, but those that do seem to rate it very highly.  I know @steppenwolf uses one.

On balance, you could do a lot worse than the Pegasus stuff.  It just works, and works very well, and the guys there are very helpful and address any issues very quickly.  The one negative is probably the universal coupler they use which uses an 8mm hole for the focuser side, and 3 opposing screws to centralise it on a smaller shaft.  This can take a fair bit of time to get right.  It is a flexible coupling which means it doesn't have to be precise, but I think the nature of the hobby means invariably we do want it precise.

Edited by RayD
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1 hour ago, RayD said:

No issues at all with the Pegasus kit.  The early ones like mine had awful brackets which flexed all over the place, but it looks like they have addressed that with new universal brackets.  Some people don't like the plastic case, and it does make it feel a little cheap compared to, say, a Sharpsky, but it is functional and protects all the innards.

Lakeside is very good, but basic, and the controller is pretty big.  Like others, I use mine without the controller via a Pegasus hub, but if you don't have one of these then the controller can be a mission to house.  Big benefit of Lakeside is the custom bracket and coupler they make for your focuser, which means the fit is perfect.

SestoSenso is very good.  Problems noted for me is the weight (it's actually fairly weighty as it's all aluminium) which has resulted in me needing additional lateral balancing at the front of my dovetail to counter it.  Also the red flashing LED is quite bright and is difficult to mask as the cover is translucent.  It can't be dimmed or switched off, which I think is an issue, and this won't be changed as the hardware doesn't let them do it (this was info from Filippo at PLL).  Finally, it fits on the micro-focuser shaft which, as most are ball bearing reduction, can lead to some slippage over time.  However, I've not found this to be an issue to date.  Plus side of this means the resolution is incredible.  For control, including speeds, torque, acceleration rates etc. the SestoSenso blows everything else out of the water.

Not used the Sharpsky, but those that do seem to rate it very highly.  I know @steppenwolf uses one.

On balance, you could do a lot worse than the Pegasus stuff.  It just works, and works very well, and the guys there are very helpful and address any issues very quickly.  The one negative is probably the universal coupler they use which uses an 8mm hole for the focuser side, and 3 opposing screws to centralise it on a smaller shaft.  This can take a fair bit of time to get right.  It is a flexible coupling which means it doesn't have to be precise, but I think the nature of the hobby means invariable we do want it precise.

All excellent advice, but just one thing my flexible coupler from Pegasus is a 5mm to 3mm, and fits perfectly on both sides, so maybe they have changed that too, and yes the new brackets are much better, I bought two recently from them to replace my old bendy ones... :)

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Deepskydad autofocus unit  uses I believe nema14 motor two flavours AF1 and soon AF2 which also has optional temp sensor and hand controller also inbuilt WiFi , fraction of the price of other makes I have two AF1 units 

www.deepskydad.com

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20 minutes ago, bottletopburly said:

Deepskydad autofocus unit  uses I believe nema14 motor two flavours AF1 and soon AF2 which also has optional temp sensor and hand controller also inbuilt WiFi , fraction of the price of other makes I have two AF1 units 

www.deepskydad.com

Yes I read a long post about these focusers and the code used in them....so I would not buy one...and don’t ask me to say on here why... 🤔

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2 hours ago, RayD said:

Not used the Sharpsky, but those that do seem to rate it very highly.  I know @steppenwolf uses one.

Very pleased with mine, I use it on two telescopes and a camera lens (via a toothed belt) but there may be lower cost alternatives.

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40 minutes ago, LightBucket said:

Yes I read a long post about these focusers and the code used in them....so I would not buy one...and don’t ask me to say on here why... 🤔

I read the same stories which, if true, is not cricket.

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1 hour ago, LightBucket said:

All excellent advice, but just one thing my flexible coupler from Pegasus is a 5mm to 3mm, and fits perfectly on both sides, so maybe they have changed that too, and yes the new brackets are much better, I bought two recently from them to replace my old bendy ones... :)

Ah ok they must have changed it.  Mine is 8mm, but then again it is an older one, so the newer ones are probably much better.  They do seem to listen and aren't afraid of accepting faults and making the necessary changes, which is a great attribute.

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Regarding the "Arduino Ascom Focuser Pro2", pity you feel your not up to it, as I've built 5 now & all work superbly, you can even buy a PCB, where you just need to add the components.... 

Also the world of stepper motors is open to you, in that you could just get the small 28BYJ-48's or the larger NEMA 14\17's with planetary gearboxes etc. and mounting them is simple with some angled aluminium.

 

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11 minutes ago, Dr_Ju_ju said:

Regarding the "Arduino Ascom Focuser Pro2", pity you feel your not up to it, as I've built 5 now & all work superbly, you can even buy a PCB, where you just need to add the components.... 

Also the world of stepper motors is open to you, in that you could just get the small 28BYJ-48's or the larger NEMA 14\17's with planetary gearboxes etc. and mounting them is simple with some angled aluminium.

 

I appreciate the enormous financial saving that can be had by making your own system.  The problem is that my life is manic at present + my soldering skills are rubbish, so I've decided to be realistic for once and not to complicate my life still more.

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2 hours ago, LightBucket said:

Yes I read a long post about these focusers and the code used in them....so I would not buy one...and don’t ask me to say on here why... 🤔

 

1 hour ago, RayD said:

I read the same stories which, if true, is not cricket.

Let’s not divert from the ops original question, (fwiw this issue has now been resolved and all coding has been rebuilt from scratch )

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2 minutes ago, bottletopburly said:

 

Let’s not divert from the ops original question, (fwiw this issue has now been resolved and all coding has been rebuilt from scratch )

No one diverted anything.  Two people noted their opinion on auto-focusers, with deliberately discrete opinions on one type being suggested, which is what the OP asked for. 

The fact the guy has now been forced to re-write the code doesn't detract from what he did originally with the copied code.

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1 minute ago, RayD said:

No one diverted anything.  Two people noted their opinion on auto-focusers, with deliberately discrete opinions on one type being suggested, which is what the OP asked for. 

The fact the guy has now been forced to re-write the code doesn't detract from what he did originally with the copied code.

Everyone make mistakes in life , now rectified.

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2 hours ago, RayD said:

Ah ok they must have changed it.  Mine is 8mm, but then again it is an older one, so the newer ones are probably much better.  They do seem to listen and aren't afraid of accepting faults and making the necessary changes, which is a great attribute.

Yes I think the first one I bought may have had an 8mm one, and I swapped for one I had that fit perfectly, but the last one i bought a couple of months ago was smaller... :)

But also like you say the service is excellent, I had a slight issue with my UPH when it arrived and within an hour of emailing them they were on my PC via teamviewer and reloaded the firmware and sorted...

Also they have a Facebook messenger page where you can contact them pretty much instantly.. :)

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I have lakeside, Moonlite and now Pegasus and the Pegasus knocks all the others into a cocked hat.

Before I had a Pegasus Ultimate Power Box I had a Moonlite with a horrible bulky serial lead and a large bulky box, it worked when nothing bumped the serial connector which went into the control box.

The Lakside is just ugly, no casing, no protection whatsoever (not really needed but for aesthetics desirable, it does use a flat ribbon cable which is pushed in and not secured and the control box is large, I also found that frequently it would lose connection in SGP.

For my 10" Truss I bought just the Pegasus motor and bracket, simply brilliant, it uses a standard RJ45 network cable, no need for power, it's tidy and really look good and works superbly with the Pegasus UPB. The brackets now come with 3 different size couplings so no more adjusting just connect and away you go.

I will slowly replace the lakeside with the Pegasus as I really believe it is superior.

I have three Pegasus Power Boxes that control all the different motors and can't see my ever changing from the Pegasus.

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I have the Sesto Senso and it works great. Its so small and very well made.

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Posted (edited)

Thanks for all the suggestions.  I went to the Practical Astronomy Show yesterday and had a good look at the offerings from Primaluce Lab, Pegasus and Hitecastro. They all looked good.

However, in the end budget had prevailed, so I've just placed an order for the new AF2 from deepskydad.com.

Edited by michaelmorris

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The Sesto Senso has been excellent in my experience. But it does lack the manual focus control offered by the Pegasus controller, so once installed, you really need to have a computer to adjust focus. Obviously for imaging this probably isn’t a problem, but it does limit the possibility of easy visual use.

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