Gregk
Pooh-Bah
Reged: 11/19/06
Posts: 1450
Loc: Gilbert Arizona
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Recently developed issue with Dec Usually resolved with re-balancing but this time not....
RA is very good The graph stays on the line oscillating mildly. I downloaded the
latest version of PHD.....it has the dec mass number I left it at 5 I tried PHDnorth south and auto all seem to indicate the same result. Useually 16calibration steps Calibration pulse set to 1000msec...Agressiveness set to 95
and Hyseryseis set to 10
Dec calibration is a little odd it does the north cal ok but the south cal does not come back or retrace the north cal to the end point but stops in between and
then starts guiding. The Dec drifts off the Axis of the graph sometime with high amplitude and sometimes with gradual amplitude drifting back to the X axis and drifitng the other way Sometimes I get large spikes in the graph
I use resist switching Any need to go to low pass mode
Thanks for any ideas
Greg
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www.azspaceblog.com/
Orion Star Shoot Pro OSC
Oiron Star Shoot II OSC
Celestron Cg-5 ASGT mount
Celestron ED80 Piggy back with william Optics 66mm APO
Celestron 6" SCT Piggy Back with william Optics 66mm APO
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BlueGrass
member
Reged: 07/25/09
Posts: 73
Loc: Wasatch Front, UT
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Greg,
I posted a very similar question in the Yahoo Stark Lab group and got a few replies with some helpful info. My CGEM with Phd did the same thing on my last outing but it continued to track without the oscillation you seem to have. Based on the replies in the Yahoo group, it seems that the failure of Phd to move completely back from N calibration is probably due to excessive backlash. That at least is one suggestion that was posted. In my case, though, Phd continued to guide without problems for about 15 minutes at which point I shutdown things for the night. So.... I'd try changing the backlash settings in the HC and see if that cures your oscillation problems. Just a thought. Good luck.
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C8 / EON 80 APO
CGEM / CG5
ST80 with SS AG setup
Canon 1000d
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drksky
super member
Reged: 09/01/09
Posts: 113
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Where the heck are the graphs accessed from in PHD?
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Tony C
AT8RC
C6-R
CG-5 ASGT
ST80 w/StarShoot Autoguider
Canon EOS 450D (Stock)
The Drinking Bird
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Gregk
Pooh-Bah
Reged: 11/19/06
Posts: 1450
Loc: Gilbert Arizona
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It passes backlash just fine during calibration
Not sure about the settings in the HC. Never monkied with those Physically there is no backlash in the dec or RA May be too tight if anything I did tweak them a bit a few months ago
Sorry drsky I dont have the graph just a log file
Greg
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www.azspaceblog.com/
Orion Star Shoot Pro OSC
Oiron Star Shoot II OSC
Celestron Cg-5 ASGT mount
Celestron ED80 Piggy back with william Optics 66mm APO
Celestron 6" SCT Piggy Back with william Optics 66mm APO
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John J
super member
Reged: 11/05/07
Posts: 190
Loc: Sioux Falls SD
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drksky
You can set phd to log it's corrections. Then you can take those logs and drop them into a spread sheet to get a graph.
JJ
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Things are looking up!
http://inskysd.org/gallery/
My Flicker Astro Site
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Gregk
Pooh-Bah
Reged: 11/19/06
Posts: 1450
Loc: Gilbert Arizona
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Sorry Tools menu then enable Graph Version 1.10 or 1.11
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www.azspaceblog.com/
Orion Star Shoot Pro OSC
Oiron Star Shoot II OSC
Celestron Cg-5 ASGT mount
Celestron ED80 Piggy back with william Optics 66mm APO
Celestron 6" SCT Piggy Back with william Optics 66mm APO
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AlanT
sage
Reged: 08/20/07
Posts: 486
Loc: 122º36' W, 47º37' N, WA USA
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I've had similar issues with my CG5 and PHD. Although I've only had maybe 6 sessions where I worked on this issue, here's my experience and opinion:
The CG5 is by nature a bit sticky in DEC because it does not any bearings on that axis.... just close fits, aluminum on aluminum. As a result, keeping the mount well groomed/lubed, the weight down, and the polar alignment right where you want are all important.
I've had my best luck by: Adjusting my polar alignment to be a few minutes West of NCP; Balancing the DEC axis S (or E depending on how you think of it) heavy so it stay biased against the worm and; Set PHD to do North only commands.
This worked for me most of the time.
al
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al
Meade 80mm APO
Celestron 6" SCT
CGE, GM-8, & CG-5 GT
ST-2000xcm, DSI Pro II, DSI Pro
( www.alberts-astro.com/astro )
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donsinger1
sage
Reged: 10/28/07
Posts: 298
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I think that your drift has more to do with polar aligment than PHD settings? Same thing happened with my CGEM, but I could guide all night with 5 minute subs no problem. But, if my PA was a tad off, the drift would appear and whatever settings I would use it did not help.
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Fun Stuff:)
Portland, OR
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Gregk
Pooh-Bah
Reged: 11/19/06
Posts: 1450
Loc: Gilbert Arizona
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It seems to be related to pre-loading the dec Please see
the images at this link where I asked the same question
I posted 3 screen shots showing the progession of the Dec
corrections
More info here see images
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www.azspaceblog.com/
Orion Star Shoot Pro OSC
Oiron Star Shoot II OSC
Celestron Cg-5 ASGT mount
Celestron ED80 Piggy back with william Optics 66mm APO
Celestron 6" SCT Piggy Back with william Optics 66mm APO
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Gregk
Pooh-Bah
Reged: 11/19/06
Posts: 1450
Loc: Gilbert Arizona
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I solved the Dec drift issue. I put the smaller guide scope back on the mount piggy back on top of the ED80 instead of the 700mm FL 70mm Orion scope. Apparently even though the dec was balanced the longer guide scope created more leverage or momentum on the DEC Axis by hanging over the ed80 by 5 inches
Greg
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www.azspaceblog.com/
Orion Star Shoot Pro OSC
Oiron Star Shoot II OSC
Celestron Cg-5 ASGT mount
Celestron ED80 Piggy back with william Optics 66mm APO
Celestron 6" SCT Piggy Back with william Optics 66mm APO
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