Date   

Re: Stepper motor mount for Losmandy GM-8

John Scherer
 

I decided to upload the design to Thingiverse.  Its just easier that way ;-)


Re: Error when compiling Wifi-Bluetooth in Release 2.22

Thomas Westerhoff
 

The good news:
The latest Wifi Addon (github checkout this morning) works with the Onstep 3.13c on my Teensy3.6.

The bad news:
I'm going out of my mind. As I said I checked out the latest code version of Github (master) this morning and now I can't compile OnStep (Teensy3.6 MaxPCB2) at all. The Arduino IDE (1.8.10) claims the Align.h file is not there, but it is there in the editor as well as in the directory, as you can see. I'm beginning to hate the Arduino IDE.


--
Thomas Westerhoff
Kirchheim Observatory /Germany
http://sternwarte-kirchheim.de/


Re: Buying an EQ5

julianporter5@...
 

@Khalid For sure I will report back here how I get on, I’m some way off but at least I think I’m going in the right direction.


Re: Buying an EQ5

Peter Dulowsky <peter.dulowsky@...>
 

This is just my experience with polar alignment and OnStep:
I have EQ5 mount with a short tube refractor that I use for visual only. I polar aligned the mount once and marked the position of the tripod legs on the pavement. For each session I just position the tripod legs on those marks and do the 3 star alignment. The error is usually around .5 deg that Onstep can handle rather well. I found no need to re-do polar alignment of the mount for every session.
When I observe away from my home location I don't use the polar scope either. I just level the mount, move the OTA to home position and turn the whole thing as necessary to get the polaris as close as practical to the dot in RDF. Then I do 3 star alignment and all is fine. Since all of my away from home locations are within 30km I do not need to play with altitude adjustment at all.


Re: Stepper motor mount for Losmandy GM-8

John Scherer
 

I'm mostly done with this 4:1 belt drive for the Losmandy GM8 and you can look at the design here.  I'm just waiting on pulleys and belt coming from china and I can test this, though I have no reason to believe it won't work. If anyone wants STL's for printing let me know. 


Re: Characterizing NEMA17 stepper motor/driver micro-stepping accuracy

--Oz--
 


Re: Buying an EQ5

Khalid Baheyeldin
 

On Thu, Jan 2, 2020 at 10:44 PM, <julianporter5@...> wrote:
Do you think aligning to the North Star with a laser will be good enough to then use the refinement function?
To get this perfectly right, you need the laser to be attached to the mount itself (not the optical tube), and you need to have it aligned (e.g. center Polaris through the polar scope opening, and then point the laser to Polaris). That way, the laser and the RA axis are aligned.

I would say that skip the laser, and just center Polaris through the polar scope opening, then do the 3-star + Refine PA routine. After all, Polaris is 40 arc minutes away from the NCP, and Refine PA should be able to handle that error range (and a bit more too).

Also try the smart phone sensors method, which I described before, and is linked to here, indoors first, then under the stars. Let us know how it works.


Re: Buying an EQ5

julianporter5@...
 

That is music to my ears. Using a polar scope is no fun at all especially when everything is at the wrong height and you are breaking your neck trying to look up and making fine adjustments.
Do you think aligning to the North Star with a laser will be good enough to then use the refinement function?


Re: Error when compiling Wifi-Bluetooth in Release 2.22

Howard Dutton
 

For now... on my MaxPCB2:  Using the latest OnStep and Wifi Add-on.

At the moment my LXD75 mount I keep around to test this is in pieces with no encoders hooked up but otherwise everything seems to fire right up as expected.  I used ESP8266 v2.4.2 in the Arduino board manager and an unpatched Encoder lib, otherwise your exact settings where known.



Re: Characterizing NEMA17 stepper motor/driver micro-stepping accuracy

fetoma
 

I fixed it Khalid.

 

Thanks,

Frank

 

From: main@onstep.groups.io <main@onstep.groups.io> On Behalf Of Khalid Baheyeldin
Sent: Thursday, January 2, 2020 6:09 PM
To: main@onstep.groups.io
Subject: Re: [onstep] Characterizing NEMA17 stepper motor/driver micro-stepping accuracy

 

Note that the first two links are to the Servo42A, and not the Servo42B version.
Listings on the eBay show that the B version has higher resolution (40.5 arc seconds).

Here is the repo for the B version.


Re: Characterizing NEMA17 stepper motor/driver micro-stepping accuracy

Khalid Baheyeldin
 

Note that the first two links are to the Servo42A, and not the Servo42B version.
Listings on the eBay show that the B version has higher resolution (40.5 arc seconds).

Here is the repo for the B version.


Re: Characterizing NEMA17 stepper motor/driver micro-stepping accuracy

fetoma
 
Edited


Re: Characterizing NEMA17 stepper motor/driver micro-stepping accuracy

Khalid Baheyeldin
 

On Thu, Jan 2, 2020 at 04:06 PM, Howard Dutton wrote:
At least the MKS servo's encoders are 16384 "CPR" (or is that 32k? regardless they have lots of counts.)
I was wondering what the resolution of the encoder is ...

360/16384 = 0.0219 degree.

But the eBay listings for the Servo42B are 0.01125 degree (40.5").

So it looks like it is 32,000 even.
Amazing that they have such a high resolution encoder for such a low cost motor.


Re: Characterizing NEMA17 stepper motor/driver micro-stepping accuracy

--Oz--
 

I am very interested in the "smart stepper" results comparison.
As I posted in the encoder thread, the price is close to the same (depending on the driver) (smart or not)
1. $14 stepper motor and $15 tmc5160 drivers = $29, (or $20 for that new driver)
2. $33 MKS-SERVO42B-Nema17-Closed-Loop-Stepper 

I have used a lot of dc brush and blushless motors over the last 4 decades, the preformance and quality make a large difference in output (in racing). I am wondering if the smart stepper is using quality materials and of a good design to make the smart part of it shine, time will tell.

Awesome work!


Re: Characterizing NEMA17 stepper motor/driver micro-stepping accuracy

fetoma
 

Wow, never thought of that. My bad.


Re: Buying an EQ5

Khalid Baheyeldin
 

On Thu, Jan 2, 2020 at 05:31 PM, Dave Schwartz wrote:
Polar scopes are highly overrated. Check out OnStep's RefinePA feature... you'll never use the polar scope again.
I second that.
Polar scopes are also very hard to collimate.

If you do a 3 star align, followed by the OnStep Refine PA, you will get very good results.
If you have plate solving and Sync to solved coordinates, the whole process is far less tedious.

Another approach you may want to try is using KStars Lite on your Android phone, go to the celestial turn on the equatorial grid, press the phone on a flat surface 90 degrees to the RA axis, and zoom in. Adjust the alt and az knobs until it is centered. The trick is finding a flat surface that the back of the phone would go on. For example, on an EQ5, if you remove the polar scope, you can press the back of the phone against where the scope should go, and the celestial pole of your hemisphere will appear. If you do it on the other end (where the cover should go on the north side), then use the opposite celestial pole.

I tried it indoors, and it should work, when the clouds go away (February or March?)


Re: Meridian flip in SGPro

Chris Vaughan
 

Yes it was in globals.h. Could also change using the SHC.


Re: Buying an EQ5

Dave Schwartz
 

Polar scopes are highly overrated. Check out OnStep's RefinePA feature... you'll never use the polar scope again.

On 2020-01-02 3:20 p.m., Joe via Groups.Io wrote:
They use the same polar scope. I Have a spare should you need one.




On Thursday, January 2, 2020, 2:01 PM, julianporter5@gmail.com wrote:

I have found a Vixen GP available at a reasonable price. Only
thing is there is no polar scope. Does anyone know if I can use an
Eq5 polar scope with it?


Re: Characterizing NEMA17 stepper motor/driver micro-stepping accuracy

Howard Dutton
 
Edited

At least the MKS servo's encoders are 16384 "CPR" (or is that 32k? regardless they have lots of counts.)  The smart stepper (that it copies) has a more advanced sensor for the encoder so should do better accuracy wise.  Possibly for our application accuracy isn't as critical since as long as the error is repeatable PEC can take care of correcting it in most cases.


Re: Characterizing NEMA17 stepper motor/driver micro-stepping accuracy

Alexander Varakin
 

You will also need a controller board in addition to this motor and it may be pretty costly.