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Guiding Calibration

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#1 CrookedEyes

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Posted 11 May 2021 - 12:35 AM

Good evening, everybody! I was wondering if I am understanding something correctly. I have an EQ6R Pro mount. Every so often, when I start the guiding and it starts doing the calibration, it'll still up quite a bit but it won't go past the "west step" and will throw an error that "the star did not move enough", or something along those lines. What I was wondering was, is this because of backlash in my mount or am I doing something incorrectly? But it only happens every once in a while. So for that reason, I feel like maybe I could have done something wrong/differently than on nights where it doesn't do that. If it is a backlash thing, is it hard to tune an EQ6R mount? Thank you in advance. I really appreciate all of your time! Clear skies, everybody!

#2 michael8554

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Posted 11 May 2021 - 03:46 AM

Hi 

 

I assume you're using NINA to guide, you didn't say ?

 

"it'll still up quite a bit but it won't go past the "west step" and will throw an error that "the star did not move enough"   ????

 

What does "up" mean ?

 

It calibrates west, returns to centre, but fails to move north ?

 

I can only compare with PHD2, you get that message if there's a lot of Dec Backlash.

 

North Cal starts, the software makes many steps, but doesn't see the star move because it's only taking up backlash.

 

On other nights you got lucky, the mount balance had already taken up backlash.

 

SOP with PHD2 is to pulse the mount north until the guidestar moves, THEN Cal.

 

Others have suggested that these non-PHD2 softwares do the clearing backlash automatically, don't know if NINA does that.



#3 AhBok

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Posted 11 May 2021 - 08:14 AM

I use PHD2 with my EQ6R Pro mount. Before doing a calibration, I move my mount west and south just a bit to ensure the worms are pushing up against the gears. Works consistently for me.
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#4 CrookedEyes

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Posted 11 May 2021 - 03:57 PM

Michael, sorry. It's supposed to say "step up" quite a bit. Meaning it'll increment for a while and then give the star didn't move enough error. And yes, I use NINA as my capture software with PHD2 for guiding.

It never goes back to center. The step count increases and increases and after so long of trying to do that, it stops the west stepping, and the rest of the calibration, and says that it didn't move enough.

Edited by CrookedEyes, 11 May 2021 - 03:59 PM.


#5 Peregrinatum

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Posted 11 May 2021 - 05:02 PM

same mount... it could be periodic error, take a few hours one night and generate some data for a PEC file and it will improve all aspects of that mount, it will take some study and time but it is well worth it, here is the reference thread that will explain everything:

 

https://www.cloudyni...-pro/?p=8879191



#6 kathyastro

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Posted 11 May 2021 - 05:42 PM

If you are calibrating for each session, I assume that you calibrate at or near your target?  You would do this if you use an ST-4 cable to connect the camera to the mount.

 

The east-west calibration is sensitive to declination.  At high declinations, the mount moves less than at low declinations.  Each calibration step moves the same number of arc-seconds of RA, but that results in fewer pixels at high declinations.  As a result, you have to increase the number of steps or the step size at high declinations, and reduce it at low declinations.

 

If you use ASCOM pulse guiding, you don't need to do this, because PHD2 has a direct connection to the mount and can read its declination.  That allows it to use a calibration made near the equator, regardless of the target's declination.  You can therefore re-use a previous calibration.


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#7 michael8554

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Posted 12 May 2021 - 07:52 AM

Post one of your PHD2 GuideLogs that includes an attempted Calibration.

 

You'll find them in the PHD2 Folder.

 

Not the DebugLog



#8 CrookedEyes

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Posted 17 May 2021 - 04:25 PM

OK, michael8554, I will. I'll have to grab one when I get home from work. I haven't had the gear set up in a week or so. Does it save historical logs or will I have to run a new calibration to generate one? I appreciate everybody throwing some ideas and pointers out there. I did notice on my EQ6R Pro, that my DEC axis has a little bit of play in it when the clutches are engaged and the mount is in the home position. The RA feels solid. I know there are ways to tune it and it looks fairly simple, I would just rather save that for a last option. I do a lot of tinkering with electronics and stuff and I've worked electronics/avionics on aircraft the last 16 years, so I'm not afraid to do it. I just know that if it doesn't actually need done, it's a waste to get in there and risk any mistakes. I will post the log as soon as I can though.

Edited by CrookedEyes, 17 May 2021 - 04:26 PM.


#9 michael8554

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Posted 18 May 2021 - 05:55 AM

The PHD2 GuideLogs (and DebugLogs) are automatically stored every time in the PHD folder.

 

Logs older than 1 month get deleted.



#10 CrookedEyes

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Posted 19 May 2021 - 07:13 PM

The PHD2 GuideLogs (and DebugLogs) are automatically stored every time in the PHD folder.

 

Logs older than 1 month get deleted.

Copy that, michael. I will get posted tonight. Thank you  very much for all of your assistance thus far!



#11 CrookedEyes

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Posted 06 June 2021 - 04:20 PM

Michael,

 

Sorry I hadn't gotten on here to post the guide log. I had issues with the laptop that controls my rig. I got it repaired and did some imaging last night. Before I took it out, I noticed some backlash with just my hands. I performed the backlash removal steps with loosening the worm housing, adjusting set screws minimally until it didn't move anymore, and ran it through 360° of rotation. I did that in both the RA and DEC because both had some movement. When I started the calibration, the North/South/East/West steps worked so much faster than it usually did. However, I got a warning that the angle between the two axes was excessive, or something along those lines. I checked the balancing, it was good. I checked the backlash with my hands and didn't feel any. Not saying there is no backlash at all but the warning was something I have gotten before too. The guiding seemed to move between sub arc second and above almost every other image. I was wondering if it could be my EQ6R mount saddle? When I tighten it, it kind of rocks up. So my telescope, on the side of the saddle knobs, sits up slightly higher. At this point, it's the only thing I can think of. But, also, here is the guide log from last night. It is rather frustrating. I certainly appreciate your time. Thank you very much!! Clear skies!

 

-Paul

Attached Files


Edited by CrookedEyes, 06 June 2021 - 11:42 PM.



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