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Re: Affordable Tripod Mounts for Onstep Steps

Khalid Baheyeldin
 

On Mon, Nov 11, 2019 at 04:13 AM, <debojyoti.pal.007@...> wrote:
I am willing to convert a normal tripod mount "SIROI SH-15 tripod" to a goto system with OnStep. Any suggestions are welcome.

First, the term "tripod mount" is not used within the amateur astronomy community, and does not mean anything.

A mount, as far as OnStep is concerned, is the part that sits on top of the tripod and has at least two axis with two motors to a) cancel the apparent motion of the sky and b) provide Goto functionality, among other things.

The tripod is just something sturdy that the mounts sits on top of.

If you mean the Sirui SH-15, this is not a mount at all. It has no motors or gears that can be moved by motors.


Re: Affordable Tripod Mounts for Onstep Steps

Howard Dutton
 

The camera is quite decent for astrophotography.

The lens FL is too long for a beginner and would required a good tracking mount to get decent results, assuming optically it's ok for astro imaging, which I seriously doubt.

Converting the tripod into a goto mount would be a dubious exercise, I already linked to the section with mounts typically converted to goto with OnStep, I will say no more.

A kit lens on the DSLR at 50mm or so can take nice wide field shots sitting on the tripod.  Taking those shots, stacking and processing them would be a valuable learning experience applicable to imaging with a telescope later.  Building a barn-door tracker that sits on that tripod should help take things to another level while spending very little.  Perhaps the zoom kit lens at longer FL would be ok then.  You will then learn about basic polar alignment, tracking, and the how and why of exposure times, ISO settings, RAW image format, etc.

If still serious you can start looking at mounts/telescopes at which point OnStep might be useful to you.


Re: Affordable Tripod Mounts for Onstep Steps

debojyoti.pal.007@...
 

Also, I am willing to use Canon 6D Mark ii with Vivitar 650-1300mm with multiple(3) 2x tele-converters giving me 2600mm, 5200mm and 10400mm focal lengths. Am I in the right path? Can I get high end telescope level photographs? 


Re: Affordable Tripod Mounts for Onstep Steps

debojyoti.pal.007@...
 

Thanks for the replies. I am willing to convert a normal tripod mount "SIROI SH-15 tripod" to a goto system with OnStep. Any suggestions are welcome.


Re: A few questions on hardware

tomofreno2000
 

On Sun, Nov 10, 2019 at 07:56 AM, Khalid Baheyeldin wrote:
I updated the info there to add that you are using TMC5160.
Thank you.  I took your advice and loaded 3.9c firmware today. Also changed slewratebasedesired to 1.75 deg/sec,
left other settings the same. Worked well, no issues. Less than 30 sec now for a 90 deg Goto. Plenty fast I think.


Re: Need help: OnStepMiniPCB Rev. 1.27x.; ESP-01 flash lost after flashing the Teensy board

Roman
 

It would be nice if I could find out which configuration would be the "right" one! I thought this group was there to help each other...

Am 08.11.19 um 22:27 schrieb Howard Dutton:

Probably you didn't configure properly and the Serial connection between them was lost.


Re: A few questions on hardware

Khalid Baheyeldin
 

On Sun, Nov 10, 2019 at 09:38 AM, tomofreno2000 wrote:
Details on the drive system are already on the Showcase page
I updated the info there to add that you are using TMC5160.


Re: A few questions on hardware

tomofreno2000
 

On Sat, Nov 9, 2019 at 03:47 PM, Khalid Baheyeldin wrote:
I am looking forward to a Youtube video in daylight of this beast slewing, with details on how the reduction was done. Add specifics in the description on the Youtube video (parts list, specs, ...etc.)
It would prove useful for others and I will add it to the showcase page.
Details on the drive system are already on the Showcase page, fifth bullet under Dobsonian. May be a while before I take a video. I have other changes I plan to make first.

I'll update the firmware later - waiting to see if there are any issues with the newer version since Howard made a lot of changes.


Re: A few questions on hardware

Gilles Gagnon
 

The TMC5160 are a nice upgrade from the TMC2130, higher current, lower heat dissipation. The only ‘surprise’ is that the direction is opposite from the 2130. Learned that when testing indoor and the scope would point to some odd place. At first I thought it was a time or location not set right but I realised that something else was wrong. Changing the appropriate #define (AXISn_REVERSE IIRC) solved the issue.

Gilles 🔭📷🏊🏻🚴‍♂️🏃🏻


Re: A few questions on hardware

Khalid Baheyeldin
 

On Sat, Nov 9, 2019 at 06:40 PM, tomofreno2000 wrote:
I downloaded version 3.7c.3 firmware
You are better off upgrading to the latest 3.x (3.9c as of now), since there was a lot of fixes.

The 5160s are working well! 
Good to see the TMC5160 are being tested by more people, and that the experience is positive.

Oh, this is on a 22.4" Dobsonian with NEMA17 motors, about 860:1 overall reduction (visual use only).
I am looking forward to a Youtube video in daylight of this beast slewing, with details on how the reduction was done. Add specifics in the description on the Youtube video (parts list, specs, ...etc.)
It would prove useful for others and I will add it to the showcase page.


Re: A few questions on hardware

tomofreno2000
 

FYI,
I downloaded version 3.7c.3 firmware, installed version 1.3 5160 drivers (https://www.digikey.com/product-detail/en/trinamic-motion-control-gmbh/TMC5160-SILENTSTEPSTICK/1460-1385-ND/9990281) with fly back diode protector boards (https://shop.watterott.com/SilentStepStick-Protector-for-Stepper-Motor-Drivers) and heat sinks (https://www.digikey.com/product-detail/en/assmann-wsw-components/V2017B/AE10837-ND/3511410), and added pull down resistors per Howard's post #13880 in this topic. I attached the heat sinks to the driver chips with a bit of epoxy.  They hang upside down above the protector boards since the driver boards are installed with driver chip down.

Chose these settings for both axis 1 and 2 (except for DRIVER_REVERSE):

#define AXIS1_DRIVER_MODEL TMC5160_QUIET      
#define AXIS1_DRIVER_MICROSTEPS 16      
#define AXIS1_DRIVER_MICROSTEPS_GOTO 8  
#define AXIS1_DRIVER_IHOLD            500 //   
#define AXIS1_DRIVER_IRUN             1500 //   
#define AXIS1_DRIVER_IGOTO            OFF //   
#define AXIS1_DRIVER_REVERSE          OFF //   
#define AXIS1_DRIVER_STATUS           OFF //

I chose QUIET because I wanted to run spreadcycle for Gotos due to the higher torque at higher rpm with it (https://www.youtube.com/watch?v=GVs2d-TOims) and because Howard recommended it (post #12982 in "A few questions about hardware" topic).

I had 2208 drivers prior to this and was limited to about 2 deg/sec Goto speed. When I went much higher than that the motors would run rough and buzz very loudly regardless of Vref = 1.3 to 1.5.

The 5160s are working well!  Can slew faster now with no issues. Motors just make a low hum  and run smoothly. I've only gone up to 3 deg/sec (for Goto) because that seems fast enough to me. Really nice to not have to tweak a pot on the driver board to set current anymore.

It seems the motor directions are different than in version 2.22 I was previously running. In 2.22 I had to reverse the Az motor direction only for correct operation. In version 3 it is the opposite, I had to reverse only Alt motor direction.

Oh, this is on a 22.4" Dobsonian with NEMA17 motors, about 860:1 overall reduction (visual use only).

As always,
Thanks Howard!


Re: New member and new build

 
Edited

I did give this a though but considered that the stepper motors on the printer don't get above 50C, this  application should be OK.
If I f do see any problems, I can reprint in PETG which has a much higher glass temperature.
There is a design listed in the wiki that uses aluminium brackets and it I can get access to tools, I will build them.

I  saw this stepper mount on Thingiverse, also for an SP but mods for a GP shouls be easy. It will allow more air flow around the motor. I have a printer and lots of spare time so why not?


Re: Onstep doesn't do corrections in Kstars

Howard Dutton
 

Agree Khalid, I was thinking the same thing yesterday.


Re: Question for other G11 owners with Onstep and SHC

Howard Dutton
 

Same behaviour with the little nema11 motors on my mount I use for testing...  about half or a third rated power results in highest slew speeds.


Re: New member and new build

Dave Schwartz
 

Looks good. My only concern would be for the temperature of the motors and its effects on the PLA.

I use the Stepperonline 400 step, 0.9A motors driven by LV8729s. Initially, I had Vref set to .45 for full current but the steady-state temperature of the motors (indoors) was almost 60C (their rated maximum is 80 but I wouldn't want to go too near that). Could not keep a finger on them longer than a few seconds. I lowered Vref to .4 and it still works fine and the steady-state temperature is now around 50C. However, being fully enclosed like that I think they will get much hotter. No firsthand experience bit I've heard that PLA starts to soften well below the temperature you extrude at.

I don't intend to hijack your thread but here's a bit on what I did in case it gives an idea to someone else...

For my Chinese EQ5 clone, I did use the Vixen SP ones which were not to difficult to modify. I think I used two of the RA ones (the DEC did not fit the DEC at all). Printed in carbon-fiber-filed PLA so its really stiff. I made a custom filler insert to hug the curve on the top of the base tab and provide a level base for the RA bracket but with a slot for the dovetail tab. I had to trim the dovetail tab to fit the RA and drill holes for the bolts (I used T-nuts on the inside). A large washer is just the correct thickness for a shim to perfectly tension the belt and also serves to conduct heat to use the mount as an additional heat sink.

Pictures of the DEC assembly and the FreeCAD-rendered RA insert are attached. That yellow stuff is the vibration damping design (also from Thingiverse) printed in TPU and you can just see the washer/spacer between the motor and the worm block. The large pulley is 48 teeth... I don't think a 60T would have fit.

On 2019-11-09 1:56 a.m., Geoff via Groups.Io wrote:
Just posted my VIxen HP stepper motor mount bracket <https://www.thingiverse.com/thing:3964641> to Thingiverse. Fits well but haven't yet run the motors.

Build on both controller and SHC has finished, flashing the firmware tonight.
Then it's time to wire up the stepper and the RJ45 cables, not looking forward to that!


Re: Question for other G11 owners with Onstep and SHC

Howard Dutton
 

Motors are stalling.  I use vref 0.4, higher than that midband resonance causes motors to stall at lesser speeds.  Actually I use 0.85A for tracking stealthChop then drop to 0 4A and switch to spreadCycle (VQUIET) for slews.


Question for other G11 owners with Onstep and SHC

Redorbit
 

Hi John
I have a fornax51 with the same onstep setup. 
This behaviour may be caused by insufficient cooling of the TMC2130 drivers,so I suppose to measure the temperature of those drivers during gotos.
I added active cooling, since than no problem with stalling/knocking motors
I hope this helps



Regards
Peter


John Scherer <jrsphoto@...> ezt írta (időpont: 2019. nov. 9., Szo, 2:54):

I have some confusion about goto rates between Onstep and the SHC.  I'm sure its just my understanding of how things are working, and maybe other G11 owners with onstep can clear things up.

I've got an older Celestron G11 mount with:
  • Onstep MaxPCB2
  • TMC2130 drivers on RA/DEC with VRef = 0.85v
  • Firmware 2.22p
  • DesiredBaseSlewRate = 1
  • Teensy 3.2 Smart Hand Controller with Firmware 1.5f
  • Orential Motor PKP244MD08B on RA/DEC
  • My Config.MaxPCB.h

My understanding is that with DesiredBaseSlewRate = 1, my maximum slew speed could be anything from .5 deg/s to 2 deg/s, based on how I have the Maximum GOTO speed set in the SHC or the Maximum Slew speed on the MaxPCB2 Wifi Configuration page. Is this correct?

Also, on the SHC, the slew rates displayed in the upper left, based on presses of the Fn buttons:
                   1/4x, 1/2x, 1x, then 2x 1x, 4x 1x, 8x 1x, 20x 1x, 48x 1x, 1/2Mx 1x, Max 1x
These rates are somewhat confusing to me and I assumed these were the same as the Maximum Goto Speed (but more selective?) in the setup menu but I'm not sure.

I ask these questions because my results seem odd to me:

Using the SHC:  Goto Speed (in settings/configuration) set to "Default Speed", if I issue a goto from the SHC, the motors start spinning as expected, but then randomly lock up, only unlocking as the goto action gets closer to the end of the movement and the motor slows down.  Its not until I select a Max Goto Speed = "Slowest", that the motors won't lock up during a slewing action.

The results are somewhat different though if I do a manual slew using N/S/E/W controls.  With the Goto Speed in settings set to "Normal", I can slew manually up to the "1/2Mx 1X" rate, with no motor lockup.

So many options here the behavior is hard to describe but hopefully someone can help.  I'd love to here from others with G11 mounts to see what max goto rates your getting?  I thought I saw that others were seeing around 2 deg/s with similar mount/motors/drivers.

Cheers

John


Re: New member and new build

 
Edited

Just posted my VIxen GP stepper motor mount bracket to Thingiverse. Fits well but haven't yet run the motors.

Build on both controller and SHC has finished, flashing the firmware tonight.
Then it's time to wire up the stepper and the RJ45 cables, not looking forward to that!


Question for other G11 owners with Onstep and SHC

John Scherer
 

I have some confusion about goto rates between Onstep and the SHC.  I'm sure its just my understanding of how things are working, and maybe other G11 owners with onstep can clear things up.

I've got an older Celestron G11 mount with:
  • Onstep MaxPCB2
  • TMC2130 drivers on RA/DEC with VRef = 0.85v
  • Firmware 2.22p
  • DesiredBaseSlewRate = 1
  • Teensy 3.2 Smart Hand Controller with Firmware 1.5f
  • Orential Motor PKP244MD08B on RA/DEC
  • My Config.MaxPCB.h

My understanding is that with DesiredBaseSlewRate = 1, my maximum slew speed could be anything from .5 deg/s to 2 deg/s, based on how I have the Maximum GOTO speed set in the SHC or the Maximum Slew speed on the MaxPCB2 Wifi Configuration page. Is this correct?

Also, on the SHC, the slew rates displayed in the upper left, based on presses of the Fn buttons:
                   1/4x, 1/2x, 1x, then 2x 1x, 4x 1x, 8x 1x, 20x 1x, 48x 1x, 1/2Mx 1x, Max 1x
These rates are somewhat confusing to me and I assumed these were the same as the Maximum Goto Speed (but more selective?) in the setup menu but I'm not sure.

I ask these questions because my results seem odd to me:

Using the SHC:  Goto Speed (in settings/configuration) set to "Default Speed", if I issue a goto from the SHC, the motors start spinning as expected, but then randomly lock up, only unlocking as the goto action gets closer to the end of the movement and the motor slows down.  Its not until I select a Max Goto Speed = "Slowest", that the motors won't lock up during a slewing action.

The results are somewhat different though if I do a manual slew using N/S/E/W controls.  With the Goto Speed in settings set to "Normal", I can slew manually up to the "1/2Mx 1X" rate, with no motor lockup.

So many options here the behavior is hard to describe but hopefully someone can help.  I'd love to here from others with G11 mounts to see what max goto rates your getting?  I thought I saw that others were seeing around 2 deg/s with similar mount/motors/drivers.

Cheers

John


Re: #define AXIS2_DRIVER_MICROSTEPS line missing from Config.h #define

Khalid Baheyeldin
 

On Fri, Nov 8, 2019 at 07:21 PM, Pete wrote:
Also the PEC Buffer integer is no longer present.  Did you remove that Howard?
It is no longer needed, since the AXIS1_STEPS_PER_WORMROT parameter tells OnStep what the buffer size will be.