seeker372011
scholastic sledgehammer
Reged: 03/05/04
Posts: 783
Loc: Sydney , Australia
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I have only just purchased my EQ6, having "upgraded" from my CG5
I am used to 20 minute subs with my CG5 and was looking to be able to do the same or better with my brand new EQ6 ,...yet after trying for 6 hours last night autoguiding has failed completely
I was trying to autoguide with PHD guiding, using the GPUSB interface; PHD calibrates fine, starts guiding but is simply unable to hold the guide star at the cross hairs and result is long star trails, even with just 5 minute subs.
PHD log shows progressively greater error in RA. Corrections in Dec looks OK -better than my CG5 generally-plus minus 2
The attached chart shows what's happening
I have tried everything I could think off..RA agressiveness-both increasing to 120% and reducing to 85%;
RA backlash various settings from 00 10 00 (default supposedly but it did not come that way from the factory) and higher and lower settings
I have also tried changing auto guide rate from 0.5 sidereal to 0.75 and even 1.0
nothing seems to work
my polar alignment was perfect and it was balanced so that the motors were pulling just slightly against the counterweight
I just can't think of what else to try.
grateful for any suggestions. This is extremely frustrating
Thank you in advance for any suggestions
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ETX 70,ED 80 on a CG5 Mount;Orion Star Shoot Deep Sky Imager,Canon 300D modded;20 x 80 LW Obies;PST;10 inch GSO dob
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Charlie Hein
Postmaster
Reged: 11/02/03
Posts: 6586
Loc: 26.06.08N, +80.23.08W
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Two questions:
Can you identify what the vertical and horizontal scales represent? Arcsec(v) and Seconds(h)? Pixels(v) and Samples(h)?
What does the "unguided" PE look like? You can disable the guide output in the advanced dialog (the "brain" icon at the bottom of the right hand of the screen).
Charlie
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Weston CSC:
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seeker372011
scholastic sledgehammer
Reged: 03/05/04
Posts: 783
Loc: Sydney , Australia
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Charlie
I don't know what unguided looks like-will need to run a trial and see
The x axis is simply samples and the y axis is pixels
thanks
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ETX 70,ED 80 on a CG5 Mount;Orion Star Shoot Deep Sky Imager,Canon 300D modded;20 x 80 LW Obies;PST;10 inch GSO dob
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Charlie Hein
Postmaster
Reged: 11/02/03
Posts: 6586
Loc: 26.06.08N, +80.23.08W
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Not knowing the sample rate it's hard to say, but if you had a fairly high sample rate then it could be that your guide cable is wired wrong. Usually when this happens the mount gets the RA signal constantly and the mount will very quickly move off target. One way to check for this is to unplug the guide cable to see if the movement stops when you do.
PS - I'm very curious about the tracking when unguided.
Charlie
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Weston CSC:
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Fabio Papa
Pooh-Bah
Reged: 03/01/05
Posts: 1130
Loc: Piacenza, Italy
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That can't happen with PHD. During calibration, it "senses" how directions are driven and adjustes itself accordingly. This problem used to afflict me with GuideDog because it didn't have a calibration routine, so if the cable was wrong, you could see what Charlie described.
Seeker, what was the exposure set in PHD? Any chance it was low as the default, 0.2 sec? If that so, you could be chasing seeing. In that case, I suggest you bring it up till about 3-4 sec. That will even out seeing.
EDIT: another thing: have you calibrated on the same star you used to guide afterwards? If you changed sky zone, you have to redo the calibration otherwise what Charlie said can become true.
Edited by Fabio Papa (08/04/08 02:49 AM)
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seeker372011
scholastic sledgehammer
Reged: 03/05/04
Posts: 783
Loc: Sydney , Australia
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Quote:
PS - I'm very curious about the tracking when unguided.
Charlie
Unfortunately I didnt check this-or rather log it on Saturday, the first time I took the scope out.It seemed fine though, for instance it held a star perfectly steady when I was focusing my imaging camera which took several minutes.
Yesterday-tracking while unguided was non existant.
I took the mount out last night to try but got clouded over in less than an hour and its cloudy tonight..but the mount behaved really badly last night almost as if it was not tracking in RA at all.
On saturday night the mount tracked for something like 6 hours and mostly kept the guide star in a 15 pixel box, even if the error kept increasing;last night the guide star didnt stay put even for a few seconds-(of course my polar alignment was very rough last night as I had only a small window of opportunity to see some stars-whereas it was perfect the previous night..but still)
so the problem is now considerably worse..forget autoguiding within a few pixels its not holding at all in RA
so a failing RA motor or some other mechanical problem with the RA drive ? or maybe the RA drive got turned off or changed to EQ North instead of EG South-can this happen with an EQ6? I need to investigate
This is getting worse - 
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ETX 70,ED 80 on a CG5 Mount;Orion Star Shoot Deep Sky Imager,Canon 300D modded;20 x 80 LW Obies;PST;10 inch GSO dob
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seeker372011
scholastic sledgehammer
Reged: 03/05/04
Posts: 783
Loc: Sydney , Australia
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Quote:
Seeker, what was the exposure set in PHD?
EDIT: another thing: have you calibrated on the same star you used to guide afterwards? If you changed sky zone, you have to redo the calibration otherwise what Charlie said can become true.
Well on saturday I used my usual 2 sec exposure and calibrated on the guide star.
Yesterday..well it was hopeless.
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ETX 70,ED 80 on a CG5 Mount;Orion Star Shoot Deep Sky Imager,Canon 300D modded;20 x 80 LW Obies;PST;10 inch GSO dob
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rmollise
Carpal Tunnel
Reged: 07/06/07
Posts: 1674
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Quote:
I have only just purchased my EQ6, having "upgraded" from my CG5
I am used to 20 minute subs with my CG5 and was looking to be able to do the same or better with my brand new EQ6 ,...yet after trying for 6 hours last night autoguiding has failed completely
This sounds like a bad guide cable/connection problem to me. Step one is to see how it tracks unguided. Without knowing that, it's impossible for us to say much more.
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Uncle Rod
Watch for Rod's New Book:
Choosing and Using a New CAT--coming in December!
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seeker372011
scholastic sledgehammer
Reged: 03/05/04
Posts: 783
Loc: Sydney , Australia
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as soon as it clears I will give it a go-look at the unguided tracking
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ETX 70,ED 80 on a CG5 Mount;Orion Star Shoot Deep Sky Imager,Canon 300D modded;20 x 80 LW Obies;PST;10 inch GSO dob
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Bill W.
Pooh-Bah
Reged: 10/09/05
Posts: 1437
Loc: Western PA, USA
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Make sure your slew setting is on 1. I had a similar problem this past weekend. As soon as I changed the slew setting to 1 from 4 my guiding worked perfectly. Before that it was ping ponging back and forth getting progressively worse with each guiding movement.
-Bill
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Orion Atlas EQ-G (EQMOD), SBIG ST-2000XM & AO7
Stellarvue SV66ED
Skunk Hollow Observatory
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seeker372011
scholastic sledgehammer
Reged: 03/05/04
Posts: 783
Loc: Sydney , Australia
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Quote:
Make sure your slew setting is on 1. I had a similar problem this past weekend. As soon as I changed the slew setting to 1 from 4 my guiding worked perfectly. Before that it was ping ponging back and forth getting progressively worse with each guiding movement.
-Bill
My slew setting was on 5 or 7 ertainly not on 1!
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ETX 70,ED 80 on a CG5 Mount;Orion Star Shoot Deep Sky Imager,Canon 300D modded;20 x 80 LW Obies;PST;10 inch GSO dob
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Bill W.
Pooh-Bah
Reged: 10/09/05
Posts: 1437
Loc: Western PA, USA
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Quote:
My slew setting was on 5 or 7 ertainly not on 1!
Hopefully that was your problem... 
-Bill
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Orion Atlas EQ-G (EQMOD), SBIG ST-2000XM & AO7
Stellarvue SV66ED
Skunk Hollow Observatory
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lawrie
Carpal Tunnel
Reged: 01/31/06
Posts: 1544
Loc: Okanagan Valley
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Which slew setting is that, you are talking about?
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Clear Skies
Lawrie
Ultima 8
Atlas EQ-G
ZenithStar 80 FD
DSI Pro - Pro II
Canon 350D
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Bill W.
Pooh-Bah
Reged: 10/09/05
Posts: 1437
Loc: Western PA, USA
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Quote:
Which slew setting is that, you are talking about?
The one that's on the left in the ASCOM interface. Mine was on 4 the other night and I couldn't get the Atlas to guide without huge errors. I played around with re-calibrating, etc. the Atlas several times because I knew the guiding corrections were overshooting their mark. As soon as I changed the slew setting to 1, the guiding performed flawlessly. I know the slew setting isn't supposed to affect the guiding but it definitely did. I was using ascom to drive my scope.
-Bill
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Orion Atlas EQ-G (EQMOD), SBIG ST-2000XM & AO7
Stellarvue SV66ED
Skunk Hollow Observatory
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seeker372011
scholastic sledgehammer
Reged: 03/05/04
Posts: 783
Loc: Sydney , Australia
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Bill:
I am using an GPUSB -ST4 connection to autoguide.
I set my slew rate to 1 as you suggested and ..it doesnt make any sense ..but it seems to be autoguiding !!!!!!!
It may be too soon to declare victory but honestly it seems to be actually autoguiding. I had to tweak RA agressiveness a tad but still
I am letting it run for several hours tonight to check the log ..but fingers crossed, touch wood (it is the 8 of the 8th isnt it).. as I watch the Olympic opening ceremony and duck out from time to time-so far so good
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ETX 70,ED 80 on a CG5 Mount;Orion Star Shoot Deep Sky Imager,Canon 300D modded;20 x 80 LW Obies;PST;10 inch GSO dob
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Bill W.
Pooh-Bah
Reged: 10/09/05
Posts: 1437
Loc: Western PA, USA
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Quote:
Bill:
I am using an GPUSB -ST4 connection to autoguide.
I set my slew rate to 1 as you suggested and ..it doesnt make any sense ..but it seems to be autoguiding !!!!!!!
 Glad to hear I could help. Believe me, I know it doesn't make sense.
-Bill
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Orion Atlas EQ-G (EQMOD), SBIG ST-2000XM & AO7
Stellarvue SV66ED
Skunk Hollow Observatory
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lawrie
Carpal Tunnel
Reged: 01/31/06
Posts: 1544
Loc: Okanagan Valley
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Thanks Bill, I would have never thought you were talking about that control. I have some issues the other night and I think I had left it set on 3 from slewing some.
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Clear Skies
Lawrie
Ultima 8
Atlas EQ-G
ZenithStar 80 FD
DSI Pro - Pro II
Canon 350D
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Bill W.
Pooh-Bah
Reged: 10/09/05
Posts: 1437
Loc: Western PA, USA
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Quote:
Thanks Bill, I would have never thought you were talking about that control. I have some issues the other night and I think I had left it set on 3 from slewing some.
If it helps both of you I'll be very happy... I know how frustrated I was on Sunday because my Atlas has guided great every time I've had it out. Good luck!
-Bill
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Orion Atlas EQ-G (EQMOD), SBIG ST-2000XM & AO7
Stellarvue SV66ED
Skunk Hollow Observatory
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lawrie
Carpal Tunnel
Reged: 01/31/06
Posts: 1544
Loc: Okanagan Valley
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Same here Bill, I had mine guiding well through EQMOD, then a few sessions ago it all went to *&^$, and my memory is, from centering a sync star I used a higher slew speed but never changed it back to 1.
Go figure..........
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Clear Skies
Lawrie
Ultima 8
Atlas EQ-G
ZenithStar 80 FD
DSI Pro - Pro II
Canon 350D
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seeker372011
scholastic sledgehammer
Reged: 03/05/04
Posts: 783
Loc: Sydney , Australia
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well reporting back from the results of last night-I can't replicate it tonight as the weather is awful..the mount certainly autoguided and though I clearly still have problems in RA its not going out of control as it was the other night
I still need to find out what is causing the problems in RA but in the meantime I am happy to report that autoguiding did its best to bring the process back under control..thanks Bill.
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ETX 70,ED 80 on a CG5 Mount;Orion Star Shoot Deep Sky Imager,Canon 300D modded;20 x 80 LW Obies;PST;10 inch GSO dob
Edited by seeker372011 (08/09/08 05:48 AM)
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