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Old 06-09-2018, 06:22 PM
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PHD2 craziness

This happened last night as PHD2 started "guiding". Bizarre, regular, high-amplitude movements in both axes... I can't begin to understand why/what would happen to cause this. Does anyone have any ideas?
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Old 06-09-2018, 06:26 PM
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Atmos (Colin)
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Looking at it, what you might want to do is drop the aggressiveness and the max movement in both RA and DEC.
I haven't used PHD2 for quite some time but it might have first been a fairly small error that it was trying to fix, moved a fair but and then got into a bounce back and forth?

Otherwise it could have just been a temporary glitch some where?
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Old 06-09-2018, 07:44 PM
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h0ughy (David)
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My mat Alan had similar issue and he was direct to the camera guiding. Took it off that by using a gpusb
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Old 06-09-2018, 07:58 PM
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Quote:
Originally Posted by Atmos View Post
Looking at it, what you might want to do is drop the aggressiveness and the max movement in both RA and DEC.
I haven't used PHD2 for quite some time but it might have first been a fairly small error that it was trying to fix, moved a fair but and then got into a bounce back and forth?

Otherwise it could have just been a temporary glitch some where?
Who knows? Seemed weird how symmetrical it was and happening on both axes at the same time.


Quote:
Originally Posted by h0ughy View Post
My mat Alan had similar issue and he was direct to the camera guiding. Took it off that by using a gpusb
I'm already using a GPUSB... in fact I wondered if the GPUSB could be faulty?


I wonder if due to the mount not being used for so long, that the older lubricant has just become very sticky in parts and is clagging up the mounts movement in parts? It will be stripped down, cleaned out and regreased after this weekend in any case....
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Old 06-09-2018, 08:34 PM
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I have a spare one if you want to try it
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Old 06-09-2018, 09:01 PM
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Quote:
Originally Posted by h0ughy View Post
I have a spare one if you want to try it
I might, thanks - I think this mount needs some TLC first though....
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Old 06-09-2018, 10:04 PM
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Few guesses:
1. It starts of drifting heavily in both directions before the corrections start. How accurate was the polar alignment?

2. Small corrections had massive effect resulting in overshooting. PHD2 did the opposite small corrections resulting in massive opposite overshooting etc.
Did you setup the mount parameters correctly? Can't remember the name... "calibration step size" maybe? If that is too large, it could cause a similar effect.

Did you do the polar alignment first? How did that go?
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Old 06-09-2018, 10:39 PM
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Polar alignment is good - permanent observatory setup.....
I've basically left PHD2 to default settings, especially in terms of calibration, I'll have to check it out further.
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Old 14-09-2018, 10:34 PM
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I have had a similar problem with MaximDL. For no reason at all there were these sudden swings in RAafter good guiding for several hours. Closed MaximDL and restarted it. No trouble for the rest of the night. Maybe the software sometimes just has a hissy fit.
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Old 15-09-2018, 07:36 AM
kens (Ken)
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There's not enough data in a screen shot. Please post the guide log. My first suspicion is a bad calibration.
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Old 15-09-2018, 09:23 AM
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I agree with Luka - either polar alignment is inaccurate or there is some significant play /flex, because dec drifted very quickly right from the start.
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Old 16-09-2018, 09:32 PM
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I suspect the issues are due to grease stiction/contamination, so will strip it down and relubricate, and adjust balance and worm gear backlash while I'm at it....
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Old 25-11-2018, 08:04 AM
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I've got back to this. Since my last woes, I've stripped down the G-11 and regreased. Everything seems pretty good - except guiding, which at present is totally non-functional.

There is something going on with the camera/image gathering arm (somewhere) but even when that is OK, the guiding is not.

With guiding off - everything is quite settled - watching the PHD2 screen shows the star field static at the mount tracks. I've stacked an image without any alignment below - it does show the mounts PE and the dec drift over 30x10s exposures and 12 minutes. The polar alignment needs work, but seems 'OK'.... Stars are a bit oval, I suspect mostly due to this drift. The PHD2 screen shows the dec drift and the mount periodic error.

When I hit the guide button, all hell breaks loose. Immediate large amplitude deviations in both axes. Watching the screen - you can see the guide star marching off the screen. When I first saw it I went looking for the cable snag....
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Last edited by Lee; 25-11-2018 at 07:09 PM.
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Old 25-11-2018, 10:25 AM
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Merlin66 (Ken)
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How many calibration steps were needed??
Have you checked the connections by using the PHD manual movement arrows??
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Old 25-11-2018, 11:44 AM
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Quote:
Originally Posted by Merlin66 View Post
How many calibration steps were needed??
Have you checked the connections by using the PHD manual movement arrows??
I'm not sure - the calibration seemed to cruise through nicely, there even seemed less backlash than I've seen before.... I'll check the log file, I assume the calibration will be in there.
I haven't used the manual buttons - I have just read a PHD troubleshooting guide, and there was something about that in there.

I would have thought the calibration passing would imply all the connections are (were) ok from the USB port of the PC right to the guide port on the mount?

I'm going to test the continuity of the cable from the GPUSB to the mount too.
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Old 25-11-2018, 12:01 PM
pjphilli (Peter)
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Whenever I have need to check the backlash of my mount or possible PHD/mount problems I use free GPINtCheck software. The version I use is for mount driven from a parallel port but I understand that there are versions to suit other interfaces.

The advantage of using it is to bypass PHD control and cause directly movement of the mount by use of the PC's arrow keys. The mount movements are small so I observe them by taking the cover off the gears of my HEQ5 Pro mount and observing the movement of the cog wheels.

https://en.freedownloadmanager.org/W...heck-FREE.html
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Old 25-11-2018, 12:05 PM
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Quote:
Originally Posted by pjphilli View Post
Whenever I have need to check the backlash of my mount or possible PHD/mount problems I use free GPINtCheck software. The version I use is for mount driven from a parallel port but I understand that there are versions to suit other interfaces.

The advantage of using it is to bypass PHD control and cause directly movement of the mount by use of the PC's arrow keys. The mount movements are small so I observe them by taking the cover off the gears of my HEQ5 Pro mount and observing the movement of the cog wheels.

https://en.freedownloadmanager.org/W...heck-FREE.html
Thanks - I'll check it out.
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Old 25-11-2018, 06:29 PM
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I've dug out some harder data from last nights session.

Images show calibration review and the screen during guiding.

Thanks for looking....

------


Corresponding log:


Guiding Begins at 2018-11-24 21:32:58
Dither = both axes, Dither scale = 1.000, Image noise reduction = none, Guide-frame time lapse = 0, Server enabled
Pixel scale = 2.14 arc-sec/px, Binning = 1, Focal length = 800 mm
Search region = 15 px, Star mass tolerance = 50.0%
Equipment Profile = test Nov 2018
Camera = SX Lodestar, full size = 752 x 580, have dark, dark dur = 2000, no defect map, pixel size = 8.3 um
Exposure = 2000 ms
Mount = Gemini Telescope .NET, connected, guiding enabled, xAngle = 163.5, xRate = 2.240, yAngle = -96.4, yRate = 3.689, parity = +/-,
X guide algorithm = Hysteresis, Hysteresis = 0.100, Aggression = 0.600, Minimum move = 0.400
Y guide algorithm = Resist Switch, Minimum move = 0.400 Aggression = 60% FastSwitch = enabled
Backlash comp = disabled, pulse = 20 ms
Calibration step = phdlab_placeholder, Max RA duration = 2500, Max DEC duration = 2500, DEC guide mode = Auto
RA Guide Speed = 7.5 a-s/s, Dec Guide Speed = 7.5 a-s/s, Cal Dec = -27.0, Last Cal Issue = None, Timestamp = 24/11/2018 9:21:24 PM
RA = 0.36 hr, Dec = -42.8 deg, Hour angle = 0.51 hr, Pier side = East, Rotator pos = N/A, Alt = 78.5 deg, Az = 209.0 deg
Lock position = 326.971, 282.160, Star position = 326.971, 282.160, HFD = 2.49 px
Frame,Time,mount,dx,dy,RARawDistanc e,DECRawDistance,RAGuideDistance,DE CGuideDistance,RADuration,RADirecti on,DECDuration,DECDirection,XStep,Y Step,StarMass,SNR,ErrorCode
1,2.511,"Mount",0.057,-0.339,-0.151,0.277,0.000,0.000,0,,0,,,,135 902,231.44,0
2,5.054,"Mount",0.423,-0.444,-0.532,0.207,-0.287,0.000,128,E,0,,,,134290,228.8 4,0
3,7.394,"Mount",0.337,-0.665,-0.512,0.444,-0.294,0.000,131,E,0,,,,128814,222.5 1,0
4,9.718,"Mount",0.224,-0.751,-0.427,0.571,-0.248,0.000,111,E,0,,,,132977,225.1 1,0
5,12.277,"Mount",0.527,-0.947,-0.774,0.610,-0.433,0.366,193,E,99,S,,,129658,221 .86,0
6,14.866,"Mount",0.082,-1.375,-0.469,1.193,-0.279,0.716,125,E,194,S,,,128490,22 9.20,0
7,17.534,"Mount",-0.132,-1.862,-0.402,1.724,-0.234,1.034,104,E,280,S,,,132078,22 4.68,0
8,20.217,"Mount",-0.738,-2.908,-0.118,2.931,0.000,1.758,0,,477,S,,, 130758,232.13,0
9,23.415,"Mount",-1.760,-4.258,0.479,4.595,0.259,2.757,116,W ,747,S,,,132077,228.76,0
10,27.315,"Mount",-3.301,-6.707,1.262,7.475,0.697,4.485,311,W ,1216,S,,,128799,216.98,0
11,32.214,"Mount",-5.046,-10.863,1.755,11.972,0.989,7.183,442 ,W,1947,S,,,136992,234.51,0
12,37.659,"Mount",-7.661,-17.068,2.501,18.691,1.410,11.215,63 0,W,2500,S,,,133863,232.68,0
13,44.008,"Mount",-11.763,-24.447,4.339,27.127,2.428,16.276,10 84,W,2500,S,,,136707,229.81,0
Guiding Ends at 2018-11-24 21:33:42
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Old 25-11-2018, 06:40 PM
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Hmmm
I a little confused by the guide screen....
What happened to the usual green cross registration.....
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Old 25-11-2018, 06:42 PM
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I believe I had hit stop in disgust.....
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