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1
DIY AstroEQ / Re: Issue with Oblong Stars, maybe RA axis?
« on: January 22, 2024, 17:32:42 »
I'm still trying to figure this out and I have some new thoughts...
Camera+Telescope in the video
0.51" asec/pixel
https://www.youtube.com/watch?v=II5HO-2NPuw
I tried zooming in on the video and I counted about 15 pixels per "jump"
15 pixels * 0.51" = 7.65 asec!!!
32 ustep, 1.8deg stepper, 360t worm
.563" asec/step
So, I don't think its a lack of stepper motor resolution...
The "jump" is periodic and it looks like between the "jumps" its tracking well...
I don't think it's missing steps as I would expect the stars to slowly drift across screen...
It "jumps" then goes right back to its original position so I'm wondering if it's a backlash issue, or an issue with the 32ustep driving of the stepper motor?
Camera+Telescope in the video
0.51" asec/pixel
https://www.youtube.com/watch?v=II5HO-2NPuw
I tried zooming in on the video and I counted about 15 pixels per "jump"
15 pixels * 0.51" = 7.65 asec!!!
32 ustep, 1.8deg stepper, 360t worm
.563" asec/step
So, I don't think its a lack of stepper motor resolution...
The "jump" is periodic and it looks like between the "jumps" its tracking well...
I don't think it's missing steps as I would expect the stars to slowly drift across screen...
It "jumps" then goes right back to its original position so I'm wondering if it's a backlash issue, or an issue with the 32ustep driving of the stepper motor?
2
DIY AstroEQ / Issue with Oblong Stars, maybe RA axis?
« on: January 20, 2024, 19:16:41 »
Hi everyone, I'm trying to troubleshoot and diagnose some issues with oblong stars. Forgive me if I'm not providing all necessary info to help track down my problem but I'm trying my best and I still have a lot to learn.
My setup is a G11 with direct drive 1.8deg steppers, 360:1 worm gear on RA and DEC and 32ustepping DRV8825s, diy mega2568 astroeq. This should be 0.563 asec/step
I'm noticing quite oblong stars with any length of exposure with my EAA setup, 2sec etc..
Askar 140mm APO f/7 with a Lodestar X2C and 0.5x Reducer
FOV Calc: Focal Ratio: 3.5 Resolution: 3.45"x3.54" per pixel Field of View: 0.72d x 0.72d
I switched to a fast 100ms exposure and no focal reducer with my ASI178MM and I took a video of it to help me diagnose:
https://www.youtube.com/watch?v=II5HO-2NPuw
The video was taken pointed at M42 with an Askar 140mm APO f/7
The FOV calulator is telling me this: Resolution: 0.51"x0.51" per pixel Field of View: 0.43d x 0.29d
I can also see this movement visually when I'm at higher magnification on jupiter.
The movement does coincide with the frequency of the RA axis noise while stepping.
So I guess, do I even have an issue or is this just what I should expect with 0.563 asec/step of the RA stepper motor?
Would it be worth it to try 0.9deg steppers or do I need to move up to timing belts and 4:1 gear reduction before the worm gear (hopefully not)?
Could this be more of an issue with backlash, skipping steps, or something else...
Thanks in advance for reading this and helping me understand...
My setup is a G11 with direct drive 1.8deg steppers, 360:1 worm gear on RA and DEC and 32ustepping DRV8825s, diy mega2568 astroeq. This should be 0.563 asec/step
I'm noticing quite oblong stars with any length of exposure with my EAA setup, 2sec etc..
Askar 140mm APO f/7 with a Lodestar X2C and 0.5x Reducer
FOV Calc: Focal Ratio: 3.5 Resolution: 3.45"x3.54" per pixel Field of View: 0.72d x 0.72d
I switched to a fast 100ms exposure and no focal reducer with my ASI178MM and I took a video of it to help me diagnose:
https://www.youtube.com/watch?v=II5HO-2NPuw
The video was taken pointed at M42 with an Askar 140mm APO f/7
The FOV calulator is telling me this: Resolution: 0.51"x0.51" per pixel Field of View: 0.43d x 0.29d
I can also see this movement visually when I'm at higher magnification on jupiter.
The movement does coincide with the frequency of the RA axis noise while stepping.
So I guess, do I even have an issue or is this just what I should expect with 0.563 asec/step of the RA stepper motor?
Would it be worth it to try 0.9deg steppers or do I need to move up to timing belts and 4:1 gear reduction before the worm gear (hopefully not)?
Could this be more of an issue with backlash, skipping steps, or something else...
Thanks in advance for reading this and helping me understand...
3
General Discussion / Re: Has anyone been successful using Satellite Tracker with AstroEQ and EQMODLX
« on: August 11, 2016, 10:37:15 »
I think I figured it out. It looks like a bug in the newer 2.6.1 beta version. I reverted back to the 2.4.9 version and everything seemed to work just fine in testing... haven't caught an actual sat yet though. Now I just have to make my scope 10x faster so that I can more easily intercept those fast little leo sats =)
4
General Discussion / Has anyone been successful using Satellite Tracker with AstroEQ and EQMODLX
« on: August 11, 2016, 02:16:06 »
Hi everyone,
I'm wondering if anyone has any experience with this, I also posted this under EQMOD and SatTracker group for looking for help. I have a lot of stuff going on with my setup and I'm actually quite surprised I made it this far =), so bear with me. I'll try to keep the problem short and sweet.
I'm having tracking issues with my motorized CG4 mount. I'm using Satellite Tracker with EQMOD, EQMODLX and AstroEQ as the motor driver.
The problem I'm having is that after intercepting, which seems to work fine (CDC and SatTrack agree on the location). Once it gets into continuous tracking mode things start to get a little wierd. My mount just starts hovering over the intercept point, it never actually follows the satellite across the sky.
I have the latest version of all software packages, and I know that eqmod and astroeq are working well with eachother as I have no problem chasing after normal sky objects. My mount should also be fast enough as I designed the setup using rather large stepper motors and am capable of using eqmod with the max sidereal rate.
Any ideas?
Thanks!
Eric
I'm wondering if anyone has any experience with this, I also posted this under EQMOD and SatTracker group for looking for help. I have a lot of stuff going on with my setup and I'm actually quite surprised I made it this far =), so bear with me. I'll try to keep the problem short and sweet.
I'm having tracking issues with my motorized CG4 mount. I'm using Satellite Tracker with EQMOD, EQMODLX and AstroEQ as the motor driver.
The problem I'm having is that after intercepting, which seems to work fine (CDC and SatTrack agree on the location). Once it gets into continuous tracking mode things start to get a little wierd. My mount just starts hovering over the intercept point, it never actually follows the satellite across the sky.
I have the latest version of all software packages, and I know that eqmod and astroeq are working well with eachother as I have no problem chasing after normal sky objects. My mount should also be fast enough as I designed the setup using rather large stepper motors and am capable of using eqmod with the max sidereal rate.
Any ideas?
Thanks!
Eric
5
General Discussion / Re: CDC Slew vs EQMod Slew, Noisy Motor Issue
« on: July 28, 2016, 08:46:21 »
That's really interesting and makes complete sense. Thanks for the code changes and the version number, everything worked without any issues. I tried everything out and there seems to be no loss of steps, and the slew is now as smooth as can be. Thanks. I also got one of the 3d printed designs done for the dec axis and I redesigned my ra axis brackets as well. My mount has really come together and is much cleaner and quieter now.
I was going to ask you about accuracy. I've reduced my backlash as much as possible and really tuned everything.
I'm still off a bit and wanted to see if I was missing anything.
Right now, I do a polar alignment using my polar scope on the cg4. Then I goto a star around polaris, usually ursa major or cassiopeia. Then I let out the clutches, center the star, and tighten back up.
The next goto seems to be quite a bit off. Like around the 3rd ring of telrad. Is this the expected accuracy until I build up alignment/sync points? Could it be that I need a more precise polar alignment?
Thanks!
I was going to ask you about accuracy. I've reduced my backlash as much as possible and really tuned everything.
I'm still off a bit and wanted to see if I was missing anything.
Right now, I do a polar alignment using my polar scope on the cg4. Then I goto a star around polaris, usually ursa major or cassiopeia. Then I let out the clutches, center the star, and tighten back up.
The next goto seems to be quite a bit off. Like around the 3rd ring of telrad. Is this the expected accuracy until I build up alignment/sync points? Could it be that I need a more precise polar alignment?
Thanks!
6
General Discussion / Re: CDC Slew vs EQMod Slew, Noisy Motor Issue
« on: July 20, 2016, 14:27:12 »
Tom, thanks for the response.
I'm glad that it looks as expected. I was wondering... given that I used relatively large steppers with a decent amount of current and torque, I might be able to achieve the same higher speed (as the >200 slew) but while still using the higher microstepping mode without losing steps. I know that this is outside of any feature or support that you would reasonably have to give, but if your not too busy and could point me to where in code I could force the microstepping mode for goto slews and slews >200 it would help me try it out.
Regardless, thanks for checking out my videos and helping. Right now I'm designing some 3d printed motor mounts for the CG4 / EQ3-2 mount, when they are done and tested I'll throw them up on thingiverse.
I'm glad that it looks as expected. I was wondering... given that I used relatively large steppers with a decent amount of current and torque, I might be able to achieve the same higher speed (as the >200 slew) but while still using the higher microstepping mode without losing steps. I know that this is outside of any feature or support that you would reasonably have to give, but if your not too busy and could point me to where in code I could force the microstepping mode for goto slews and slews >200 it would help me try it out.
Regardless, thanks for checking out my videos and helping. Right now I'm designing some 3d printed motor mounts for the CG4 / EQ3-2 mount, when they are done and tested I'll throw them up on thingiverse.
7
General Discussion / Re: CDC Slew vs EQMod Slew, Noisy Motor Issue
« on: July 20, 2016, 06:23:11 »
You have done a great job with AstroEQ and all together this is quite an amazing project you have kept going.
It's been a while since I've worked on this project but a recent injury has me back at fine tuning my telescope setup =)
A year later, all my previous posts are still valid and I'm back at trying to debug this.
Although I believe I've found the best settings for these motors with the Goto speed in the astroeq config, using the DRV8825 instead of the A4988, and the current limit I have set. I'm still not too happy when my motors are operating in the so called "NOISY" range. I'm willing to change motors and try other things to achieve the 100% smooth operation I've witnessed during slower speed EQMOD Control Pad Slewing.
Here are some tests using EQMOD Control Pad Slewing, first with the RA Axis then the DA Axis.
EQMOD Control Pad Slewing
RA - Axis
180 SLEW E - SMOOTH, W - SMOOTH
195 SLEW E - SMOOTH, W - SMOOTH
198 SLEW E - SMOOTH, W - SMOOTH
199 SLEW E - SMOOTH, W - NOISY
200 SLEW E - SMOOTH, W - NOISY
201 SLEW E - NOISY , W - NOISY
205 SLEW E - NOISY , W - NOISY
280 SLEW E - NOISY , W - NOISY
DEC - Axis
180 SLEW E - SMOOTH, W - SMOOTH
195 SLEW E - SMOOTH, W - SMOOTH
198 SLEW E - SMOOTH, W - SMOOTH
199 SLEW E - SMOOTH, W - SMOOTH
200 SLEW E - NOISY, W - NOISY
201 SLEW E - NOISY, W - NOISY
205 SLEW E - NOISY , W - NOISY
280 SLEW E - NOISY , W - NOISY
Things I'm noticing, if the noisy vs smooth operation is caused by stepping modes, then I notice that the RA axis has a difference between E and W at a couple of slew rates, 199 and 200. This difference is probably just caused in code by a > condition vs a >= condition or something to that degree. That isn't a big deal but I figure that I would mention it. I'm really just trying to chase after the Smooth vs Noisy operation of my steppers.
Now All Gotos within CDC result in the "NOISY" movement.
I am linking a video I just made on youtube to hopefully help out. The settings I have right now are definately tolerable although I'm worried that this noisy/resonate movement might result in losing steps during the deacceleration and acceleration phase of a movement, especially since I see the timing belt resonate which I did capture on video toward the end. Had I only ever seen the "noisy" operation I probably wouldn't be too interested in quietting it down, but because I know the 100% smooth operation is possible, I'm attempting to try and get all the movements like that. I'm an engineer trying to solve problems that people didn't even know they had (till I messed them up) =) JK
EQMOD Slews
https://youtu.be/aevdcVKxXMU
CDC Gotos
https://youtu.be/aaZtv6WAE4g
Any and all help is greatly appreciated, maybe the best answer is to change my motors from 0.9 deg steppers to 1.8 deg or change the type/torque/current rating. What do you think?
Thanks for all your great/hard work and help!
It's been a while since I've worked on this project but a recent injury has me back at fine tuning my telescope setup =)
A year later, all my previous posts are still valid and I'm back at trying to debug this.
Although I believe I've found the best settings for these motors with the Goto speed in the astroeq config, using the DRV8825 instead of the A4988, and the current limit I have set. I'm still not too happy when my motors are operating in the so called "NOISY" range. I'm willing to change motors and try other things to achieve the 100% smooth operation I've witnessed during slower speed EQMOD Control Pad Slewing.
Here are some tests using EQMOD Control Pad Slewing, first with the RA Axis then the DA Axis.
EQMOD Control Pad Slewing
RA - Axis
180 SLEW E - SMOOTH, W - SMOOTH
195 SLEW E - SMOOTH, W - SMOOTH
198 SLEW E - SMOOTH, W - SMOOTH
199 SLEW E - SMOOTH, W - NOISY
200 SLEW E - SMOOTH, W - NOISY
201 SLEW E - NOISY , W - NOISY
205 SLEW E - NOISY , W - NOISY
280 SLEW E - NOISY , W - NOISY
DEC - Axis
180 SLEW E - SMOOTH, W - SMOOTH
195 SLEW E - SMOOTH, W - SMOOTH
198 SLEW E - SMOOTH, W - SMOOTH
199 SLEW E - SMOOTH, W - SMOOTH
200 SLEW E - NOISY, W - NOISY
201 SLEW E - NOISY, W - NOISY
205 SLEW E - NOISY , W - NOISY
280 SLEW E - NOISY , W - NOISY
Things I'm noticing, if the noisy vs smooth operation is caused by stepping modes, then I notice that the RA axis has a difference between E and W at a couple of slew rates, 199 and 200. This difference is probably just caused in code by a > condition vs a >= condition or something to that degree. That isn't a big deal but I figure that I would mention it. I'm really just trying to chase after the Smooth vs Noisy operation of my steppers.
Now All Gotos within CDC result in the "NOISY" movement.
I am linking a video I just made on youtube to hopefully help out. The settings I have right now are definately tolerable although I'm worried that this noisy/resonate movement might result in losing steps during the deacceleration and acceleration phase of a movement, especially since I see the timing belt resonate which I did capture on video toward the end. Had I only ever seen the "noisy" operation I probably wouldn't be too interested in quietting it down, but because I know the 100% smooth operation is possible, I'm attempting to try and get all the movements like that. I'm an engineer trying to solve problems that people didn't even know they had (till I messed them up) =) JK
EQMOD Slews
https://youtu.be/aevdcVKxXMU
CDC Gotos
https://youtu.be/aaZtv6WAE4g
Any and all help is greatly appreciated, maybe the best answer is to change my motors from 0.9 deg steppers to 1.8 deg or change the type/torque/current rating. What do you think?
Thanks for all your great/hard work and help!
8
General Discussion / Re: CDC Slew vs EQMod Slew, Noisy Motor Issue
« on: October 08, 2015, 20:22:18 »
Thanks So Much!
I will take some video when I get home. For now let me post the specs.
0.9 deg stepper, 68 oz/inch, Nema 17
http://cdn.sparkfun.com/datasheets/Robotics/42BYGHM809.PDF
RA: 4:1 reduction with GT2 pulleys and belt
DEC: 2.8:1 reduction with GT2 pulleys and belt
DRV8825, I also tried the A4988 but results were better with the DRV8825
I have them set to about 1.7A/phase (I'm using a good quality DMM and I have decent test equipment for any other measurement that could help)
Celestron CG-4... As far as I can tell, an EQ3-2
New version with steel tripod legs
The worst part of the resonance/vibration is during acceleration/deceleration. It seems that there are frequencies that the motors don't like during this (However, again this is only during CDC slews). Accel/Decel works great when it's only EQMod.
I will also test out the <200/>200 slew rates from EQMod. However I remember never wanting to go above 200 in EQMOD just for this reason. So what you are saying makes perfect sense.
I will take some video when I get home. For now let me post the specs.
0.9 deg stepper, 68 oz/inch, Nema 17
http://cdn.sparkfun.com/datasheets/Robotics/42BYGHM809.PDF
RA: 4:1 reduction with GT2 pulleys and belt
DEC: 2.8:1 reduction with GT2 pulleys and belt
DRV8825, I also tried the A4988 but results were better with the DRV8825
I have them set to about 1.7A/phase (I'm using a good quality DMM and I have decent test equipment for any other measurement that could help)
Celestron CG-4... As far as I can tell, an EQ3-2
New version with steel tripod legs
The worst part of the resonance/vibration is during acceleration/deceleration. It seems that there are frequencies that the motors don't like during this (However, again this is only during CDC slews). Accel/Decel works great when it's only EQMod.
I will also test out the <200/>200 slew rates from EQMod. However I remember never wanting to go above 200 in EQMOD just for this reason. So what you are saying makes perfect sense.
9
General Discussion / CDC Slew vs EQMod Slew, Noisy Motor Issue
« on: October 08, 2015, 17:19:33 »
So I noticed something and was wondering if there was an explanation for it. If I set the Goto speed in the astroeq config to something like 200 and I set the EQMod slew rate to 200, the behavior of the motors is completely different.
EQmod slew with the control pad arrows for 200 will be smooth and quiet. CDC slew (goto at 200) on the other hand will be noisy and I get a lot of unwanted resonance out of the motor.
I've tried many different goto rates in the astroeq config, but all the ones I have tried are never as smooth and quiet as the EQMod slew with the controller...
Any ideas?
EQmod slew with the control pad arrows for 200 will be smooth and quiet. CDC slew (goto at 200) on the other hand will be noisy and I get a lot of unwanted resonance out of the motor.
I've tried many different goto rates in the astroeq config, but all the ones I have tried are never as smooth and quiet as the EQMod slew with the controller...
Any ideas?
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