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Old 08-12-2013, 08:19 PM
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seeker372011 (Narayan)
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PHD guiding not bale to control in dec

Ok I have been using phd for ages, ever since I moved on from guide dog oh about 10 years ago maybe.

Anyway I has real trouble ..before cloud came over, rendering the whole exercise null and void...with guiding in dec.

Ultimately the only way I could get any sort of guiding..and it was still pretty spiky in the graph..was to increase the guiding duration from the default 100 ms to 400 ms

I haven't had to do that this last ten years! This is quite unusual..I have previously found that any problems are in either dec not calibrating at all..usually a cable fault..or to do with balance of the scope of the mount and ra doesn't guide well either in such a case.

Now I couldn't actually manage an image because by the time I did all this..took some experimentation it was clouded over..but just asking..has anyone else had a similar experience . What do you think is creating this?

Thanks in advance

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Old 08-12-2013, 10:29 PM
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redbeard (Damien)
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Me too,

I have been using PHD for about 2 1/2 years with no problem, until last summer where I cannot use DEC guiding at all. I get major spikes and it ruins all my images.

If I turn it off and I have good polar alignment, I can get 5 min subs with 'almost' round stars. I have to reset it after 3 images or so. It appears that the scope is OK. But I cannot find out why and I have tried everything.

I have a Meade 10" LX200GPS.

However, my DEC drive controller on the scope died, and it was replaced with a new DEC controller by Bintel and the problem started after this.

Not sure what to do and can anyone else help us both? Please.

Cheers,

Damien.
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Old 09-12-2013, 06:47 AM
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BlackWidow (Mardy)
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Have both of you tried to go back to guide dog to see if the issues is software or hardware.

Mardy
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Old 09-12-2013, 11:24 AM
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redbeard (Damien)
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Never used guide dog,

do you know if it is any good?
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Old 09-12-2013, 11:53 AM
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mithrandir (Andrew)
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Narayan, PHD with my ST80 and Atik guide cam has always needed cal step size of about 1000 to get the recommended ~15 steps.

Are you using v1 or v2 of PHD?
You a sure it isn't trying to guide on a hot pixel? Dark frames work better with some cameras than others so you could trial both ways.
Slightly defocused stars work better than absolutely sharp ones.
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Old 09-12-2013, 05:03 PM
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Quote:
Originally Posted by redbeard View Post
Never used guide dog,

do you know if it is any good?
It is 10 year old software and was quickly overtaken by PHD. Used it with a CG 5 cable plugged into the hand controller and a serial to USB convertor

Don't know if it will work with a GPUSB.. Probably not unless it has been updated sincrbj last used it
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Old 09-12-2013, 05:10 PM
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Quote:
Originally Posted by mithrandir View Post
Narayan, PHD with my ST80 and Atik guide cam has always needed cal step size of about 1000 to get the recommended ~15 steps.

Are you using v1 or v2 of PHD?
You a sure it isn't trying to guide on a hot pixel? Dark frames work better with some cameras than others so you could trial both ways.
Slightly defocused stars work better than absolutely sharp ones.
Andrew I am actually referring not to the calibration step but the actual pulse duration... As I said I had to crank it up heaps and then got " spiky " guiding graph rather than the nice smooth graph without too much oscillation that one hopes for. Never had to do this before in the 10 years or so I have been using PHD so wondering about what might cause this?all of a sudden,not a new scope or anything


Calibration works just fine evèn at default though like you I set it at 1000 just to cut down the number of steps. And no it's not a hot pixel or a saturated star . It was actually guiding just now as smoothly as I hope to achieve

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Old 09-12-2013, 05:43 PM
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Quote:
Andrew I am actually referring not to the calibration step but the actual pulse duration... As I said I had to crank it up heaps and then got " spiky " guiding graph rather than the nice smooth graph without too much oscillation that one hopes for. Never had to do this before in the 10 years or so I have been using PHD so wondering about what might cause this?all of a sudden,not a new scope or anything
Narayan, PHD won't always use the maximum pulse length. It is just there to set an upper limit.
I'd suggest you check the balance on the mount. Any slop in the gearing makes for bad guiding. If you keep the RA slightly east heavy and the dec a bit unbalanced you'll keep the worms loaded and it won't flop around.
I gave up trying to do photography with a C8 on my CG5-ASGT and bought a G11.
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Old 09-12-2013, 07:45 PM
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In this instance phd kept going to the max, that's what surprised me; and when I kept cranking up the max it kept hitting that ceiling. As I said I have never seen that happen.

The scope was as always east heavy, but now I am not sure of Dec.

I think maybe I balanced it as usual, when I replaced the eyepiece with the camera maybe it was unbalanced in Dec. maybe. Maybe that is what caused the grief. Well can only try next time it's clear on a weekend.
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Old 09-12-2013, 07:47 PM
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Damien

I also had problem guiding in Dec once before. Turned out to be a cable fault. Try a new cable. Caused me a lot of grief before I tracked it down.and the fix was simple. Now I always keep a spare cable.

Narayan
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Old 09-12-2013, 10:00 PM
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redbeard (Damien)
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Thanks Narayan,

I have replaced the guide camera cable twice but not the mount cable, although I have replaced the RS232 to USB part of the mount cable for one that works with Win7.

All the other software I use seems to work perfectly, Alignmaster, Ascom, Direct RS232 to scope, (built my own controller with a pic), etc
So I'm not sure it is the mount cable as it is sending data.

With the DEC in PHD turned off, and if I have good polar alignment, the scope tracks for about on average 25 min before I stop and start PHD again so comms appear to be OK as is the hardware. I've got reasonable PEC on RA, and have turned it off/on with little difference. Balance is good. Goto works great, especially in high precision with objects centred. Camera lined up, everthing is tight and solid.

I have had a new dec motor drive board fitted by Bintel and the issues have kinda started after that, but everything else works with this board in DEC so I'm not sure where to look. I've used different laptops with different versions of PHD as well.

As I mentioned before, it was working fine for about 2 1/2 years until one night all of a sudden, no worky. It's got me stumped.

Cheers,

Damien.
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