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Re: Servocat Sky program

 

¿ªÔÆÌåÓý

Beautiful cigar galaxy Gabriel.?
Thanks for the detailed info. I will try not I ever get a chance to image. Still haven't tried the new firmware ?.?

Mickey?


On Jan 26, 2025, at 4:09?PM, Gabriel Wiklund via groups.io <gabriel.wiklundholeshot@...> wrote:

?

[Edited Message Follows]

Hello Mickey,
?
I was waiting for your response lol!
?
Anyway: (not the same email since things have changed since then)

I have not used PHD2 but NINA has a Direct Guider for dithering so it should be able to dither directly with the Meade Generic driver. Nothing i have tried since field rotation has worked as excellent dither for me but i guess that changes when using a field rotator.
?
Here is the rough NINA walk through i created in response to your email back then.. i am not a tutorial guy but i at least it's something. Sorry for doing this on my smartphone:
?
If you have any specific questions i am happy to answer them.
?
In infrastructure mode with a virtual serial port and the correct IP adress + the latest Meade Generic driver it's just a question of choosing the Meade Generic driver in the NINA mount drop down list and everything just works.
?
This is how i use NINA:
?
1. Mount pointing at 0.00 and 63.00 (i have put marks on the groundboard and altitude bearings), or you could just point at Polaris or NCP.

2. Inside the house i press play on my automated 2-star alignment sequence, after that is done it goes back to 0.00 63.00.
This is how the sequence looks:
<2star.png>
?
Then i choose the target in NINAS framing wizard, press slew (not slew and center). Then after the mount has stopped moving
i hit solve and sync. Then slew again, it always puts the object in the middle or almost in the middle, so from here instead of jumping back and forth i just do the last fine centering with NINAS scope control (like a virtual handpad).?
?
Then i run my Sequence which looks like this:

<nina2.png>
?
It took a while to dial in a bulletproof autofocus routine with the 30" but i have found the right settings, 3 exposures per focus point and using the 15 brightest stars i think was the most important settings.
?
The reason i solve and sync every 75 exposures is so that Nexus is updated on exactly where it is pointing for the correct drive rates, not sure if this makes any difference, just an idea i had.
?
I don?t use center after drift anymore since it can get stuck jumping back and forth trying to center if the accuracy is set to below 2.5 arc minutes.
Having the the correct gear ratios set goes a loong way so i don?t mind re-centering now and again, one night i did not have to re-center for 2.5 hours.
?
Here is my latest image:
Edit: Not latest image, but latest stack of an already uploaded image!

Best Regards
Gabriel
?
?


Re: Servocat Sky program

 
Edited

Hello Mickey,
?
I was waiting for your response lol!
?
Anyway: (not the same email since things have changed since then)

I have not used PHD2 but NINA has a Direct Guider for dithering so it should be able to dither directly with the Meade Generic driver. Nothing i have tried since field rotation has worked as excellent dither for me but i guess that changes when using a field rotator.
?
Here is the rough NINA walk through i created in response to your email back then.. i am not a tutorial guy but i at least it's something. Sorry for doing this on my smartphone:
?
If you have any specific questions i am happy to answer them.
?
In infrastructure mode with a virtual serial port and the correct IP adress + the latest Meade Generic driver it's just a question of choosing the Meade Generic driver in the NINA mount drop down list and everything just works.
?
This is how i use NINA:
?
1. Mount pointing at 0.00 and 63.00 (i have put marks on the groundboard and altitude bearings), or you could just point at Polaris or NCP.

2. Inside the house i press play on my automated 2-star alignment sequence, after that is done it goes back to 0.00 63.00.
This is how the sequence looks:
?
Then i choose the target in NINAS framing wizard, press slew (not slew and center). Then after the mount has stopped moving
i hit solve and sync. Then slew again, it always puts the object in the middle or almost in the middle, so from here instead of jumping back and forth i just do the last fine centering with NINAS scope control (like a virtual handpad).?
?
Then i run my Sequence which looks like this:

?
It took a while to dial in a bulletproof autofocus routine with the 30" but i have found the right settings, 3 exposures per focus point and using the 15 brightest stars i think was the most important settings.
?
The reason i solve and sync every 75 exposures is so that Nexus is updated on exactly where it is pointing for the correct drive rates, not sure if this makes any difference, just an idea i had.
?
I don?t use center after drift anymore since it can get stuck jumping back and forth trying to center if the accuracy is set to below 2.5 arc minutes.
Having the the correct gear ratios set goes a loong way so i don?t mind re-centering now and again, one night i did not have to re-center for 2.5 hours.
?
Here is my latest image:
Edit: Not latest image, but latest stack of an already uploaded image!

Best Regards
Gabriel
?
?


Re: Servocat Sky program

 


Hello Gabriel, I sent this awhile back to you directly, I expect I got the email address wrong.

Mickey

Michael "Mickey" Huffman?
From:finman42@...
To:gabriel.wiklundholeshot@...
Thu, Jan 9 at 6:52 PM
Hello Gabriel and Happy New Year, I hope you are well and your imaging is moving forward.?

I have not been imaging and have not yet had a chance to try the new firmware. My wife's recovery from hip replacement surgery has gone slow though she is doing well and then on December 31st I contracted the flu bug. I am finally well but the weather has been terrible and terrible for imaging.

I have a question statement, didn't you say you were using PHD2 with NINA and the Nexus? Aren't you connecting through Sharpcap for PHD2,? I may be wrong about the PHD2.
Are you able to dither or do you just stop the run and start again.?
If you are using NINA and Nexus would you mind repeating your steps to me on how you accomplish this feat.?

I know you gave me the answer but I have misplaced that email and forgot, LOL.

Anyway thanks for the help.

Mickey


On Sunday, January 26, 2025 at 01:22:29 AM EST, Gabriel Wiklund via groups.io <gabriel.wiklundholeshot@...> wrote:


I was thinking of replacing my laptop in the observatory but I can't find the CD to install the Servocat Sky program on the "new" laptop, is there a way to download the software without a CD?
?
Best regards
Gabriel?


Re: Local SYNC activated or not ?

 

Thanks Gary !
It is what I was thinking.
It' a big scope (36") and I thus have to go to the SC main unit to see the status of the LED.
Not a big deal, but is it possible to change the handpad yellow LED ??
I ask this because I have some skilled electonicians guys at work that may be able to weld a new LED AS SOON AS it's not a too small machined welded LED....
I didn't bring the handpad from observatory so can't open to show them.
Does anyone has a picture of inlet of hand pad to see the type of LED and how it is welded ?
Thanks !
?
?
?


Re: Servocat Sky program

 

Hi Gabriel. I will respond by email.
BC
?


Re: Local SYNC activated or not ?

 

AutoLOCK (and thus Local Sync) are both on - the led on your handpad isn't working. You'll need to refer to the front of the ServoCAT for confirmation. Note it works reliably (the sync function) so if you push it for 1/4 second or so you can rest assured it is on (or off if it was on).?
?
g.
?
?


Re: Local SYNC activated or not ?

 

On Sat, Jan 25, 2025 at 06:06 PM, Raphael Guinamard wrote:
Dear all, dear Gary,
I was at observatory last night and tested again my yellow Led problem.
I was pretty sure last time that when I pressed the local synch on my hand pad no yellow led lit on Handpad nor main unit, but yesterday it behaved differentely.
But maybe I was too tired...
Yesterday when I Press the local synch, the yellow led local synch on main unit turn on (and the red aux also), but the yellow led on the hand pad didn't turned on.
See the video enclosed.
I believe my yellow LED on hand pad is damaged, no ?
Is there a way to test it ? (like on a car when you put your key in, all the led turn on)
Thanks for reply
?
Sorry, it seems the .mov video can't be seen on the group
Here is a .MP4 video.
Rapha?l


Servocat Sky program

 

I was thinking of replacing my laptop in the observatory but I can't find the CD to install the Servocat Sky program on the "new" laptop, is there a way to download the software without a CD?
?
Best regards
Gabriel?


Re: Local SYNC activated or not ?

 

Dear all, dear Gary,
I was at observatory last night and tested again my yellow Led problem.
I was pretty sure last time that when I pressed the local synch on my hand pad no yellow led lit on Handpad nor main unit, but yesterday it behaved differentely.
But maybe I was too tired...
Yesterday when I Press the local synch, the yellow led local synch on main unit turn on (and the red aux also), but the yellow led on the hand pad didn't turned on.
See the video enclosed.
I believe my yellow LED on hand pad is damaged, no ?
Is there a way to test it ? (like on a car when you put your key in, all the led turn on)
Thanks for reply
?


Re: Local SYNC activated or not ?

 

Raphael,

The wireless HC - well both the wired and the WL - get their led signals FROM the ServoCAT. Thus it will not 'work' stand alone.?

g.




------ Original Message ------
From "Raphael Guinamard via groups.io" <rguinamard@...>
Date 1/18/2025 4:19:25 PM
Subject Re: [ServoCAT] Local SYNC activated or not ?

Hello Gary
Yes I had exactly the same conclusion as yours : if the red aux light turned on => I was in autolock, so local synch had been activated => the 2 yellow LED on Handpad and on main unit SHOULD have been on. But they were not.
I don't know what happened
I will recheck next time at observatory, as I was tired at end of observation.?
I brought the handpad at home (far away from observatory),and today I turned it on, pushed the guide slow button to make sure I was on guide speed, then pushed the local synch button. The yellow LED didn't turned on neither.
But maybe this is normal as the handpad was not connected to the servocat main unit ?
Am I correct ? could anyone test this on its own handpad to check if the yellow local synch LED turned on -or not- when NOT connected to main unit ?
Regards
Rapha?l


Re: Local SYNC activated or not ?

 

Hello Gary
Yes I had exactly the same conclusion as yours : if the red aux light turned on => I was in autolock, so local synch had been activated => the 2 yellow LED on Handpad and on main unit SHOULD have been on. But they were not.
I don't know what happened
I will recheck next time at observatory, as I was tired at end of observation.?
I brought the handpad at home (far away from observatory),and today I turned it on, pushed the guide slow button to make sure I was on guide speed, then pushed the local synch button. The yellow LED didn't turned on neither.
But maybe this is normal as the handpad was not connected to the servocat main unit ?
Am I correct ? could anyone test this on its own handpad to check if the yellow local synch LED turned on -or not- when NOT connected to main unit ?
Regards
Rapha?l


Re: Local SYNC activated or not ?

 

Raphael,

Good day sir.?

Ok ... so if the red AUX light came on then you were in AutoLOCK mode... and to be in AL mode you had to be in Local Sync mode. So the yellow SYNC led on the HC should be on as well as the SYNC led on the front of the ServoCAT. I'd check it again.?

g.




------ Original Message ------
From "Raphael Guinamard via groups.io" <rguinamard@...>
Date 1/18/2025 1:03:54 PM
Subject [ServoCAT] Local SYNC activated or not ?

Dear all,?
I was not using the local sync function but after reading manual I believe it is quite powerfull to find faint objects.
So yesterday at end of observation I tried to activate it on M42 with the idea to find the horse head just after.
The Aux switch was up. I'm quite sure I was in guide mode, but not 100% sure.
When I pressed for approx 1 s the Local Sync on my (wireless) Handpad, the yellow led didn't turned on.
The Yellow LED sync on panel of main unit didn't turned on neither, BUT the? Left-most RED marked "AUX" LED turned on.
So it seems something happen....
?
I pressed again the Local Sync on my (wireless) Handpad, the? RED "AUX" then turned off. Both yellow led on HC and main panel still off.
Any idea what's happening ?
?
I have a version3 (updated from version 2 a few month ago)
Thanks for reply
Rpha?l


Local SYNC activated or not ?

 

Dear all,?
I was not using the local sync function but after reading manual I believe it is quite powerfull to find faint objects.
So yesterday at end of observation I tried to activate it on M42 with the idea to find the horse head just after.
The Aux switch was up. I'm quite sure I was in guide mode, but not 100% sure.
When I pressed for approx 1 s the Local Sync on my (wireless) Handpad, the yellow led didn't turned on.
The Yellow LED sync on panel of main unit didn't turned on neither, BUT the? Left-most RED marked "AUX" LED turned on.
So it seems something happen....
?
I pressed again the Local Sync on my (wireless) Handpad, the? RED "AUX" then turned off. Both yellow led on HC and main panel still off.
Any idea what's happening ?
?
I have a version3 (updated from version 2 a few month ago)
Thanks for reply
Rpha?l


Re: SOLVED: Re: Problem tracking with ArgoNavis and ServoCat on my 20" f/4

 

Hi Richard, Gary,
thanks for this additional info.
Regards,
Mike
?


Re: SOLVED: Re: Problem tracking with ArgoNavis and ServoCat on my 20" f/4

 

Mike,?

At the moment and for the foreseeable future a DSC will need to be connected and have to have been aligned before you can do a PC Planetarium connection. The DSC is what has the knowledge of the Universe.?

The PC USB is used for all PC communications as spelled out in the user manual that is on the CD that ships with the system. The setup is trivial. There are at the moment I believe 2 ASCOM drivers. The original, created by Peter Eschman, is available and is the most commonly used one. The other is in alpha testing if I'm not mistaken.?

Gary?




------ Original Message ------
From "Mike Greenhill-Hooper via groups.io" <sally.greenhill@...>
Date 1/9/2025 10:45:03 AM
Subject Re: [ServoCAT] SOLVED: Re: Problem tracking with ArgoNavis and ServoCat on my 20" f/4

Hi Richard and Gary,
thanks very much for your quick and positive responses on this.? I probably will just start by using my laptop not the hub mini-PC you use (sorry for the non technical terms). I use the ASCOM platform and EQMOD driver for my SkyWatcher mount (via CdC), so am reasonably familiar with this approach.? What I would like to confirm is the use of the USB cable that plugs into the PC USB socket on my ServoCat to connect my laptop to the ServoCat and run the planetarium program from the laptop. This cable was supplied I thought for just updating mount parameters through the ServoCat Sky program.? Can it be used for mount control as well?? I don't want to cause any damage. Also do I leave alone the existing connection to AN (DSC socket on the ServoCat) and have the AN running as well or not?
?
I have tried to find discussion threads with all the info I need, but still have these questions.? Are there any video tutorials on all of this?
?
I'm impressed with the amount of automation that is becoming possible. I have an Astrocrumb filter slide and have to manually push and pull to change the filter. I do need to modernize my methods, however, on step at a time, I think!
?
Kind regards,
Mike
?


Re: SOLVED: Re: Problem tracking with ArgoNavis and ServoCat on my 20" f/4

 

Mike,
?
The USB port on the ServoCAT gives Stellarium access to Argo Navis--a clever type of serial data pass thru that Gary designed.
?
Stellarium will place a target style marker overlay on top of the star map showing you where the telescope is currently pointing.
?
Stellarium is a bit of a computer asset hog, but wow, I sure do enjoy using it.
?
I broke a Toshiba laptop when I was using it outside as the telescope control.? It was well below freezing outside and I brought it inside my humid house.? ?To replace the laptop, I purchased the Eagle4S (no display) which has a bunch of customized telescope specific features:? a small telescope (5 degrees fov) for a built in SQL meter, power switching, temperature-controlled dew heater power jacks, a bunch of USB ports, a Thunderbolt 4 port, a GPS, a weather station (humidity, pressure, and temperature) and some cool queries that let you harvest all that data, power monitoring (needed if you use a battery to power your rig).
?
I just attached an ACME threaded rod and stepper motor to the Astrocrumb strip to move the strip to the desired filter.? I think there is a better design to put a pin wheel style gear on the system to make it like the old style dot matrix printers and I am going to make a version 2.0 later this year.? I do enjoy changing filters from my recliner!? I also programmed my focus motor to change with each filter.
?
If you can slew, focus and change filters remotely you have a mostly remote system.? In the future, I plan to add the ability to avoid the 2 star alignment and auto power up of the rig and I could place my rig up in an unattended remote location.
?
Richard


Re: SOLVED: Re: Problem tracking with ArgoNavis and ServoCat on my 20" f/4

 

Hi Richard and Gary,
thanks very much for your quick and positive responses on this.? I probably will just start by using my laptop not the hub mini-PC you use (sorry for the non technical terms). I use the ASCOM platform and EQMOD driver for my SkyWatcher mount (via CdC), so am reasonably familiar with this approach.? What I would like to confirm is the use of the USB cable that plugs into the PC USB socket on my ServoCat to connect my laptop to the ServoCat and run the planetarium program from the laptop. This cable was supplied I thought for just updating mount parameters through the ServoCat Sky program.? Can it be used for mount control as well?? I don't want to cause any damage. Also do I leave alone the existing connection to AN (DSC socket on the ServoCat) and have the AN running as well or not?
?
I have tried to find discussion threads with all the info I need, but still have these questions.? Are there any video tutorials on all of this?
?
I'm impressed with the amount of automation that is becoming possible. I have an Astrocrumb filter slide and have to manually push and pull to change the filter. I do need to modernize my methods, however, on step at a time, I think!
?
Kind regards,
Mike
?


Re: Servo Cat moves after goto completes.

 

¿ªÔÆÌåÓý

Ok, It will be the end of January before we get to use it again. I am almost certain that it is Gen3. I just wish it didn¡¯t do the second movement.? A little over a year ago one of the spur gears came lose inside the Alt drive. We were able to slide it back into place and get it going again. At that time, we tested all the setscrews both internal and the capstan. All were good.

Bob

?

From: [email protected] <[email protected]> On Behalf Of K9RX - Gary via groups.io
Sent: Wednesday, January 8, 2025 5:20 PM
To: [email protected]; [email protected]
Subject: Re: [ServoCAT] Servo Cat moves after goto completes.

?

Bob,?

?

Sorry - I think you missed the point. IF it is the latest version firmware then my point is a) that is why you are seeing a lower value and yet it moves again and b) there is indeed a last mover after that...?

?

so if there's slippage in the drive rollers that would account for it.?

?

Also: the fact that it is getting worse suggests strongly it is a loose drive roller.?

?

But I would suggest you check the version. If it powers up and the red AUX light comes on before the green SLEW light (ignore the HC light for this) then it is the latest version. (if you have a Gen2 it might show the yellow SPm light before the green SLEW light)

?

g.

?

?

?

?

------ Original Message ------

From "bobrose500 via groups.io" <bobrose500@...>

Date 1/8/2025 6:24:51 PM

Subject Re: [ServoCAT] Servo Cat moves after goto completes.

?

No, it goto¡¯s essentially almost 0¡¯s. Then moves and ends up something like 0.30:0.55. ?Back when we first noticed it, the numbers were around 0.10 :0.10. I might suspect the gears are getting play in them except after nearly getting it right, the motors wind back up and it moves decidedly away.

Firmware has not been updated in years. Probably should do that first.

Bob

?

From: [email protected] <[email protected]> On Behalf Of K9RX - Gary via groups.io
Sent: Wednesday, January 8, 2025 4:02 PM
To: [email protected]; [email protected]
Subject: Re: [ServoCAT] Servo Cat moves after goto completes.

?

The algorithm is designed, assuming you are using the latest version firmware, to always end up in the direction of sidereal tracking. So - it does a GOTO. Then it gets the offset again from the DSC and does a 2nd GOTO. If after the 2nd one the distance to the object is still more than ... I think it was 0.04¡ã, it will do a third one, if it is within that it will not do another.?

?

But it then checks to see which direction the last move was - was it in the direction of sidereal or not. If not it will move the axis away in the direction opposite sidereal, more than the backlash value (typically 0.7¡ã or so)... and then it will do one final GOTO. THIS should put it both at 0.00 on each axis as well as tracking immediately (no backlash to unwind).?

?

Thus you could and would see behavior like you are describing - but it should still end up < 0.05¡ã away.?

?

g.

?

?

?

?

------ Original Message ------

From "bobrose500 via groups.io" <bobrose500@...>

Date 1/8/2025 5:29:29 PM

Subject Re: [ServoCAT] Servo Cat moves after goto completes.

?

Gary,

Thanks for the reply. I will check the drive rollers. It seems to split the error between the axes. I will check both. ?Hadn¡¯t really thought about it being slipping as it goes to the target stops for about a half second then motors past. It is pretty much acquiring the target in the initial goto. No overshoot or undershoot there. Just immediately after acquisition, the motors start back up and drive past. I is like it has built in offset.

Bob

?

From: [email protected] <[email protected]> On Behalf Of K9RX - Gary via groups.io
Sent: Wednesday, January 8, 2025 2:23 PM
To: [email protected]; [email protected]
Subject: Re: [ServoCAT] Servo Cat moves after goto completes.

?

Hello Bob,

?

Forgive me - I saw this and forgot to respond to it ...?

?

So - this sounds like a drive roller is slipping due to a loose grub screw. Check to see which axis is off first - then focus on the drive roller for that axis.?

?

Gary Myers

StellarCAT

?

?

?

?

------ Original Message ------

From "bobrose500 via groups.io" <bobrose500@...>

Date 1/2/2025 10:26:17 PM

Subject [ServoCAT] Servo Cat moves after goto completes.

?

I am asking on behalf of my clubs SC install. It is a 40" with a Nexus (not Pro). All GOTO's are via the Nexus. A couple of years ago just after a GOTO finished the SC would motor about 10 arcminutes from the target. Display on Nexus indication something like `0.10. It has progressively increased over the past year or so. Last outing it was nearly 1 degree. I can issue another GOTO and it will zero in a little better. Strange thing is it will nearly zero the target stops then proceed again to a position now that is 50+ arcminutes. Anybody got any ideas what the issue is? We are calling it overshoot. In it is acquiring the target then moving away.

Bob


Re: Servo Cat moves after goto completes.

 

Bob,?

Sorry - I think you missed the point. IF it is the latest version firmware then my point is a) that is why you are seeing a lower value and yet it moves again and b) there is indeed a last mover after that...?

so if there's slippage in the drive rollers that would account for it.?

Also: the fact that it is getting worse suggests strongly it is a loose drive roller.?

But I would suggest you check the version. If it powers up and the red AUX light comes on before the green SLEW light (ignore the HC light for this) then it is the latest version. (if you have a Gen2 it might show the yellow SPm light before the green SLEW light)

g.




------ Original Message ------
From "bobrose500 via groups.io" <bobrose500@...>
Date 1/8/2025 6:24:51 PM
Subject Re: [ServoCAT] Servo Cat moves after goto completes.

No, it goto¡¯s essentially almost 0¡¯s. Then moves and ends up something like 0.30:0.55. ?Back when we first noticed it, the numbers were around 0.10 :0.10. I might suspect the gears are getting play in them except after nearly getting it right, the motors wind back up and it moves decidedly away.

Firmware has not been updated in years. Probably should do that first.

Bob

?

From: [email protected] <[email protected]> On Behalf Of K9RX - Gary via groups.io
Sent: Wednesday, January 8, 2025 4:02 PM
To: [email protected]; [email protected]
Subject: Re: [ServoCAT] Servo Cat moves after goto completes.

?

The algorithm is designed, assuming you are using the latest version firmware, to always end up in the direction of sidereal tracking. So - it does a GOTO. Then it gets the offset again from the DSC and does a 2nd GOTO. If after the 2nd one the distance to the object is still more than ... I think it was 0.04¡ã, it will do a third one, if it is within that it will not do another.?

?

But it then checks to see which direction the last move was - was it in the direction of sidereal or not. If not it will move the axis away in the direction opposite sidereal, more than the backlash value (typically 0.7¡ã or so)... and then it will do one final GOTO. THIS should put it both at 0.00 on each axis as well as tracking immediately (no backlash to unwind).?

?

Thus you could and would see behavior like you are describing - but it should still end up < 0.05¡ã away.?

?

g.

?

?

?

?

------ Original Message ------

From "bobrose500 via groups.io" <bobrose500@...>

Date 1/8/2025 5:29:29 PM

Subject Re: [ServoCAT] Servo Cat moves after goto completes.

?

Gary,

Thanks for the reply. I will check the drive rollers. It seems to split the error between the axes. I will check both. ?Hadn¡¯t really thought about it being slipping as it goes to the target stops for about a half second then motors past. It is pretty much acquiring the target in the initial goto. No overshoot or undershoot there. Just immediately after acquisition, the motors start back up and drive past. I is like it has built in offset.

Bob

?

From: [email protected] <[email protected]> On Behalf Of K9RX - Gary via groups.io
Sent: Wednesday, January 8, 2025 2:23 PM
To: [email protected]; [email protected]
Subject: Re: [ServoCAT] Servo Cat moves after goto completes.

?

Hello Bob,

?

Forgive me - I saw this and forgot to respond to it ...?

?

So - this sounds like a drive roller is slipping due to a loose grub screw. Check to see which axis is off first - then focus on the drive roller for that axis.?

?

Gary Myers

StellarCAT

?

?

?

?

------ Original Message ------

From "bobrose500 via groups.io" <bobrose500@...>

Date 1/2/2025 10:26:17 PM

Subject [ServoCAT] Servo Cat moves after goto completes.

?

I am asking on behalf of my clubs SC install. It is a 40" with a Nexus (not Pro). All GOTO's are via the Nexus. A couple of years ago just after a GOTO finished the SC would motor about 10 arcminutes from the target. Display on Nexus indication something like `0.10. It has progressively increased over the past year or so. Last outing it was nearly 1 degree. I can issue another GOTO and it will zero in a little better. Strange thing is it will nearly zero the target stops then proceed again to a position now that is 50+ arcminutes. Anybody got any ideas what the issue is? We are calling it overshoot. In it is acquiring the target then moving away.

Bob


Re: Servo Cat moves after goto completes.

 

¿ªÔÆÌåÓý

No, it goto¡¯s essentially almost 0¡¯s. Then moves and ends up something like 0.30:0.55. ?Back when we first noticed it, the numbers were around 0.10 :0.10. I might suspect the gears are getting play in them except after nearly getting it right, the motors wind back up and it moves decidedly away.

Firmware has not been updated in years. Probably should do that first.

Bob

?

From: [email protected] <[email protected]> On Behalf Of K9RX - Gary via groups.io
Sent: Wednesday, January 8, 2025 4:02 PM
To: [email protected]; [email protected]
Subject: Re: [ServoCAT] Servo Cat moves after goto completes.

?

The algorithm is designed, assuming you are using the latest version firmware, to always end up in the direction of sidereal tracking. So - it does a GOTO. Then it gets the offset again from the DSC and does a 2nd GOTO. If after the 2nd one the distance to the object is still more than ... I think it was 0.04¡ã, it will do a third one, if it is within that it will not do another.?

?

But it then checks to see which direction the last move was - was it in the direction of sidereal or not. If not it will move the axis away in the direction opposite sidereal, more than the backlash value (typically 0.7¡ã or so)... and then it will do one final GOTO. THIS should put it both at 0.00 on each axis as well as tracking immediately (no backlash to unwind).?

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Thus you could and would see behavior like you are describing - but it should still end up < 0.05¡ã away.?

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g.

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------ Original Message ------

From "bobrose500 via groups.io" <bobrose500@...>

Date 1/8/2025 5:29:29 PM

Subject Re: [ServoCAT] Servo Cat moves after goto completes.

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Gary,

Thanks for the reply. I will check the drive rollers. It seems to split the error between the axes. I will check both. ?Hadn¡¯t really thought about it being slipping as it goes to the target stops for about a half second then motors past. It is pretty much acquiring the target in the initial goto. No overshoot or undershoot there. Just immediately after acquisition, the motors start back up and drive past. I is like it has built in offset.

Bob

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From: [email protected] <[email protected]> On Behalf Of K9RX - Gary via groups.io
Sent: Wednesday, January 8, 2025 2:23 PM
To: [email protected]; [email protected]
Subject: Re: [ServoCAT] Servo Cat moves after goto completes.

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Hello Bob,

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Forgive me - I saw this and forgot to respond to it ...?

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So - this sounds like a drive roller is slipping due to a loose grub screw. Check to see which axis is off first - then focus on the drive roller for that axis.?

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Gary Myers

StellarCAT

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------ Original Message ------

From "bobrose500 via groups.io" <bobrose500@...>

Date 1/2/2025 10:26:17 PM

Subject [ServoCAT] Servo Cat moves after goto completes.

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I am asking on behalf of my clubs SC install. It is a 40" with a Nexus (not Pro). All GOTO's are via the Nexus. A couple of years ago just after a GOTO finished the SC would motor about 10 arcminutes from the target. Display on Nexus indication something like `0.10. It has progressively increased over the past year or so. Last outing it was nearly 1 degree. I can issue another GOTO and it will zero in a little better. Strange thing is it will nearly zero the target stops then proceed again to a position now that is 50+ arcminutes. Anybody got any ideas what the issue is? We are calling it overshoot. In it is acquiring the target then moving away.

Bob