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Re: Runaway tracking

 

Steve,

Ok ... try the test I had indicated - remove the DSC cable AT the front of the ServoCAT ... see if it then is fully controllable by the handpad.?

This is an important test - if the ServoCAT works a bunch of times w/o the DSC cable plugged in.?

If it does - and you see this (wrong) action again (note you can do a daytime alignment, doesn't need to be very accurate, just to test this all out so you can possibly fix it BEFORE it gets dark) ... check the GUIDE values on the DSC. Do they seem right? Are they 'going down' as the GOTO slew progresses? Also - try disengaging and seeing if the object is indeed at where you told it to go (of course this would be at night after a real alignment).?

You can also go to MODE ENCODER on the AN and see, as the ServoCAT moves, do the encoder values change.?

This could be a slipping or non-functional DSC encoder ... if the motor speed seems correct (important distinction) but it seems to take longer to do a GOTO then it might be that the AN is not getting encoder readout partially or at all.?

Daytime alignment:?

Point the scope straight up (assuming you have that as your ALT REF position) and north. Then turn on, do your FIX ALT REF. Now go to MODE ENCODER, enter. Now move the ALT ONLY down until it matches your LAT. Go to MODE ALIGN STAR, find Polaris, and hit enter. You now have 2/3rd of the alignment done...?

open a planetarium program, one that will show stars at the current time and show their current ALT/AZ position. Find one in the sky at that time - go to MODE ENCODER, move the scope to the ALT/AZ position it shows for that star (oh - bright star, so that it is in the BRIGHT STAR catalog)... now go back to ALIGN STAR, enter, find that star - hit enter. You're now aligned. (of course for this you do need the DSC cable plugged in the whole time)

g.



------ Original Message ------
From "Steve Goldberg via groups.io" <sgoldberg124@...>
To [email protected]; "K9RX - Gary via groups.io" <amateurK9RX@...>
Date 2/1/2025 4:28:25 PM
Subject Re: [ServoCAT] Runaway tracking

Gary and Bill,
You are making us think back a couple of hours after we have slept. ;)
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This was the first GOTO of the night. The object was not in the field, too much power eyepiece. Changed to a lower power, then pushed a button to move the scope. She claimed it was moving too fast. So I moved the "speed button" down to the slower speed. She then pushed another button and the scope kept going at the same slower speed, Did the 3-button stop. Pressed a button for 2 seconds or more to reset, and when taking finger off the button the scope kept moving. We did several times.
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Gary, you asked about the speed of the movement. The speed was the same as the last slew speed? button push. Don't think it was accelerating, we didn't let run that long to see.
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That is where were stopped for the night.
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Steve & Amelia
On 02/01/2025 1:19 PM CST K9RX - Gary via groups.io <amateurk9rx@...> wrote:
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Hi Steve and Amelia,?
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Questions for you... you said Amelia did a GOTO and had no issue... was that the first GOTO or was that later in the session (you mention you were tired indicating possibly it had been working for a while)??
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When you say "the scope kept moving, faster than tracking" ... did it appear to accelerate to a stable speed - then continue at a (stable) speed OR did it continue to speed up going much faster than the SLEW rate (rate you'd see when doing a GOTO)??
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Try unplugging the DSC cable from the front of the ServoCAT --- then see if the HC can control the scope for slewing. Push the button - does it accelerate up to speed, go at a constant speed as long as you are holding a button, then decelerate to a stop when you let go of the button??
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Does it operate in JOG speed the same, only slower overall??
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If the motor encoder were not being seen the motor would, due to lack of feedback from its encoder, speed up VERY fast with no perceptible acceleration and it would not stop with a 3 button stop (it MIGHT stop ?- but rarely and only randomly - and it would start up again pretty fast).?
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Gary?

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