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Re: Servocat unit not responding

 

Maybe. Like a sequence of random coincidences. Argo burned out, then Servocat stopped working due to a broken cable HC, then the user incorrectly installed the jumper on SkyCommander. Although it worked for him before. It is easier to assume a single source of the problem. It is stated above.
Re: Servocat unit not responding

 

You may have a faulty hand controller cable. The hand controller may be getting power and ground but failing to transmit data to the ServoCAT.
I just had this happen on my own telescope.
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BC
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Re: Servocat unit not responding

 

I assumed that a 12V external battery was used. If the user uses AC/DC, then it is his mistake. It has been explained many times and everywhere that high voltage cannot be used in the presence of moisture. It is life-threatening.
Re: Servocat unit not responding

 

Are you certain you have a good 12v supply?
Re: Servocat unit not responding

 

My apologies - I only read the first line about the Sky Comm not being recognized.?
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Which version ServoCAT do you have - is the hand pad connected using a thin round cable with a straight plug at each end? If so this is a Gen1 or Gen2 ServoCAT.?
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If not, if it is connected with a flat cable and phone type plugs at each end this is a Gen3.?
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In either case - if I'm reading this correctly after the green SLEW light comes on the yellow HC light remains off - correct??
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If so IF it is a Gen3 are the lights on the HC on (red light by GUIDE fast, green light by the GOTO led)??
If a Gen2 is the red light on (slide the speed switch all the way up to be sure)??
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g.
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Re: Servocat unit not responding

 

The problem is that his device does not respond to the motors control buttons. I do not know how this is connected to the internal fuse. Perhaps it only switches off the motor control chips, but this is also doubtful. But this does not depend on the connection speed with DSC.
Re: Servocat unit not responding

 

see my reply to Rajeev re reversed power.?

Gary


------ Original Message ------
From "alg via groups.io" <alg@...>
Date 3/26/2025 5:49:36 PM
Subject Re: [ServoCAT] Servocat unit not responding

I think you mixed up the polarity of power supply for both Argo and Servo§³at. The consequences are sad.
Re: Servocat unit not responding

 

Hello Rajeev,
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Sorry for the late reply.?
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So as to why the AN isn't working I can't directly address that. If you accidentally powered it up with reverse voltage I believe it would have been damaged. The ServoCAT has a built in protection device and fuse that would have blown (the fuse) had power been reversed to it. Replacing the fuse (there's an extra one supplied with the unit as it is non-standard sized) would have brought it back up.?
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As for the Sky Commander not working. Was it working previously? Depending on the version of the Sky Commander - the full white box can use 19200 baud. The newer model with a black box uses 9600 max. So if it is the latter there is another jumper that has to be switched that forces the ServoCAT to communicate using 9600 baud. Right to me direct if you need a copy of the instructions on how to do this if you need to. Also confirm the Sky Commander is set to these appropriate baud.?
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Gary Myers
StellarCAT
Re: Servocat unit not responding

 

I think you mixed up the polarity of power supply for both Argo and Servo§³at. The consequences are sad.
Servocat unit not responding

 

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I'm looking for help in trying to figure out an issue with my (newly replaced) Servocat unit.? Everything was working until a few days ago, when my Argo Navis unit seems to have suddenly died.? (I've tried with a couple of external 12v supplies, and with fresh batteries, and the unit doesn't turn on at all; the display stays dark.). So I went back to my old Sky Commander unit (which seems to be working as before), and switched the jumpers inside the Servocat to the "SC" setting.
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But the unit still does not detect the Sky Commander (the "DSC" light never comes on).? I then disconnected the DSC and tried manually slewing using the hand controller, but neither of the ALT or AZ motors seem to respond anymore.? I've unplugged and replugged all cables, but had no luck.? When I turn on the unit (with or without DSC plugged in), the HC light goes green and the AUX light is orange briefly.? Then the AUX light turns off, and the Slew light turns green.
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Any ideas on what the problem could be, or anything else I can do to diagnose the issue?
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Thanks,
- Rajeev
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Re: My first ServoCAT Autoguide "production" images

 

That sounds like a great tip, big thanks!
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/Gabriel
Re: My first ServoCAT Autoguide "production" images

 

As for the azimuth bearings, take a piece of 24 or 26 gauge sheet metal, cut it about 2 inches or 50mm wide about 12 to 16 inches or 355mm long, then get some Velcro use the fuzzy piece and cut a 2inch by 2inch square and the stick that piece to the end of the metal strip. Now spray the Velcro piece with whatever substance you use, the with the Velcro fuzzy side up place it next to one of the 3 plastic bearing with pressure and by hand spin the scope slowly, do it 3 times by going to each plastic bearing, no runs, no drip, no errors.?

? That is a trick Mike Zammit taught me.

Mickey

On Monday, March 17, 2025 at 01:03:36 PM EDT, Gabriel Wiklund via groups.io <gabriel.wiklundholeshot@...> wrote:


Thank you Mickey! Actually i did just that for the altitude bearings, but for the azimuth i could not access the surface with a cloth so i "cheated" but i know not to take corners again, not worth the risk!
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/Gabriel
Re: My first ServoCAT Autoguide "production" images

 

Thank you Mickey! Actually i did just that for the altitude bearings, but for the azimuth i could not access the surface with a cloth so i "cheated" but i know not to take corners again, not worth the risk!
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/Gabriel
Re: My first ServoCAT Autoguide "production" images

 

Beautiful image Gabriel , an important note about applying spray to the bearings, never spray directly to the bearings, because of the mirror and the over spray, always take a cloth or paper towel and apply the spray to the towel and rub on the bearing both to clean and reapply.

Mickey

On Monday, March 17, 2025 at 07:54:52 AM EDT, Gabriel Wiklund via groups.io <gabriel.wiklundholeshot@...> wrote:


Here is 1 hour and 15 minutes on The Pinwheel Galaxy from yesterday. Last time i imaged this galaxy the seeing was very bad, i had better luck this time.
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226 x 20s using ServoCAT Autoguide in PHD2. Speaking of guiding i made a discovery a few days ago, i wiped the Alt bearing surface just in case there was dirt there, that removed the layer of silicon spray that was there which i had applied for pherhaps 1 month ago.
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This caused the Alt guiding to go crazy, probably due to stiction. So i applied a new layer of silicon spray and like magic the guiding was back to around 1 arc second again.
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However one has to be very careful that the silconspray does not end up on the groundboard where the roller rides since it will loose grip. (happened last time). Apart from that when spraying the Az surface it can end up on the power rail under the center bolt, and silicon does not transmit electric current (also learnt that the hard way).
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And Like Gary has mentioned, it can attract dirt, but in my case it has not done that since it's winter here when i observe with no desert dust or so.
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Clear skies
/Gabriel
Re: My first ServoCAT Autoguide "production" images

 

Here is 1 hour and 15 minutes on The Pinwheel Galaxy from yesterday. Last time i imaged this galaxy the seeing was very bad, i had better luck this time.
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226 x 20s using ServoCAT Autoguide in PHD2. Speaking of guiding i made a discovery a few days ago, i wiped the Alt bearing surface just in case there was dirt there, that removed the layer of silicon spray that was there which i had applied for pherhaps 1 month ago.
?
This caused the Alt guiding to go crazy, probably due to stiction. So i applied a new layer of silicon spray and like magic the guiding was back to around 1 arc second again.
?
However one has to be very careful that the silconspray does not end up on the groundboard where the roller rides since it will loose grip. (happened last time). Apart from that when spraying the Az surface it can end up on the power rail under the center bolt, and silicon does not transmit electric current (also learnt that the hard way).
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And Like Gary has mentioned, it can attract dirt, but in my case it has not done that since it's winter here when i observe with no desert dust or so.
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Clear skies
/Gabriel
Re: Argo-Navis & ServoCat off in AZ

 

Hi Sam,

Your scope is fitted with incremental encoders and they have no inherent zero reference point.
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The zero reference point for the altitude encoder when the unit is first powered on is determined by whatever angle you have in the FIX ALT REF menu (typical) 90 and whatever angle in altitude the OTA happens to be.
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When the FIX ALT REF step is performed, the altitude zero reference point is re-established by it.
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If you are using AUTO ADJUST ON (and you should) when you perform the two-star alignment or any subsequent alignment, the altitude zero reference point can be automatically adjusted. Usually this is a "tweak" from the reference point you initially established when you did the FIX ALT REF.
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So that's the altitude encoder but you are asking about the azimuth encoder. How is its zero reference point established, you may ask?
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The rule for it is simple. The zero reference point is the arbitrary orientation the scope happens to be in azimuth when you power it on.
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Whereas the zero reference point for the altitude encoder is important, for the azimuth encoder it matters not.
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So for example if the scope happened to be oriented to the north when you powered it on, the zero reference point would be 0.
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MODE ENCODER provides a readout of the encoders within "encoder space".
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MODE AZ ALT provides a readout of which way the scope is pointing in a topographic sense, like that from a compass and sextaant, but only after you have performed a star alignment and if your location is established in SETUP LOCATION and time in SETUP TIME. It works by starting with the RA/Dec position the scope is pointing at and then performing the classical transformation to convert it to a topocentric geographic coordinate pair.

I hope this in-depth answer helps clarify things for you.
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--
Gary Kopff
Managing Director
Wildcard Innovations Pty. Ltd.
20 Kilmory Place
Mount Kuring-Gai NSW 2080
Australia
Phone +61-2-9457-9049
sales@...
https://www.wildcard-innovations.com.au
Re: Argo-Navis & ServoCat off in AZ

 

Hey Sam... long long time no hear. I'm trying to remember - was it not you that (Jean and) I met way back in like 2001 or so - you had an observing site near I think it was Huachuca City??

Anyway... so first what I'd do is to go to MODE ENCODER and confirm the AZ axis is reading as you move the scope.?

Second are you sure you are hitting the FIX ALT REF twice ... once to get in to the mode and once to do the action??

Last check the MOUNT TYPE. Make sure it is set as I believe ALT AZ MOUNT.?

The sequence generally is - or at least what I do - point the scope roughly north and to the ALT REF position (most have this as 90)... turn on the system - hit enter twice. Now you can go to MODE ENCODER and the AZ should read 0 (the ALT the ALT REF value).?

g.


------ Original Message ------
From "Sam Selig via groups.io" <bigdob1400@...>
Date 3/5/2025 9:34:46 AM
Subject [ServoCAT] Argo-Navis & ServoCat off in AZ

Maybe its old age, but I cant resolve this issue. When I set up (Obsession f5/20) I basically have the scope pointing North and at 90'. Power on the Cat and Argo and it goes through initialing and gives beep synch tone and do a fix alt ref. Now if I go to Mode Encoder I see my AZ is almost always about 90' as if pointing east? Why is it nolonger reporting 0 when pointing north? This deviation makes alignment and/manual targeting a bit more challenging. Did I miss somethin? Suggestions??
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Thanks
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Argo-Navis & ServoCat off in AZ

 

Maybe its old age, but I cant resolve this issue. When I set up (Obsession f5/20) I basically have the scope pointing North and at 90'. Power on the Cat and Argo and it goes through initialing and gives beep synch tone and do a fix alt ref. Now if I go to Mode Encoder I see my AZ is almost always about 90' as if pointing east? Why is it nolonger reporting 0 when pointing north? This deviation makes alignment and/manual targeting a bit more challenging. Did I miss somethin? Suggestions??
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Thanks
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Re: My first ServoCAT Autoguide "production" images

 

Thank you Mickey, very much appreciated!
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/Gabriel
Re: My first ServoCAT Autoguide "production" images

 

Excellent images Gabriel, you keep improving with every run.

Mickey

On Friday, February 28, 2025 at 11:51:46 AM EST, Gabriel Wiklund via groups.io <gabriel.wiklundholeshot@...> wrote:


As the weatherman promised our skies cleared up Wednesday and yesterday Thursday so i was finally able to test Autoguiding on actual capture.
It works well and i can confirm that dither also works very well with ServoCAT. It almost always settled from a dither without messsing up the next sub which was often not the case with my Sky-Watcher mount even though i used "Spiral" instead of "Random" for dither there as well (to avoid backlash).
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I dither 1 pixel on my guidecamera which is 4.30 arc seconds = about 14 pixels on my DSLR, it problably would not hurt to dither more than every 10 frames as i did.
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241 x 15s (1h 15s) on The Sunflower Galaxy. Large view on Astrobin recommended:
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449 x 20s (2.5h) on NGC 3180 (looks like a flower too in my opinion). Large view recommended:
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Astrobin link to a PHD2 screenshot: (the total RMS there is 0.94" arc seconds, for the most part during capture it was around 1.2 -1.3" arc seconds).
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PHD2 calibration (no warnings):

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At the moment i use a guidespeed of 7 arc seconds per second in ServoCAT Sky and 0.20 x Sidereal in PHD2.
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/Gabriel
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