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Old 20-10-2008, 06:30 PM
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AlexN
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More PHD problems.. :(

It seems every time I fix one problem, another one arises... I've yet only once managed to get auto guiding to work so far, so its really becoming a pain...

Last night, when the scope was pointed to the west, it would calibrate in RA, but not in dec.. hence, dec guiding was disabled, and PE caused problems in > 5min subs

Then when I pointed over to the east, it would not calibrate in RA... its error was saying that it couldn't move the star far enough.

Keep in mind that the night before it was not having this problem... the balance had not changed as the scopes were left on the mount....

I checked cable connections quite a few times, I also parked the mount and rebalanced it a few times just to make sure, when it was in the west, the scopes were slightly heavier than the counterweight and vice versa in the east, Balancing dec was kind of touchy, as the 4" APO + QHY8 is quite a bit heavier than the ST80 + DBK, but i got the balance to the point where no matter where i pushed the scope to, it would stay put where it stoped, and when pushed in any direction it would come to a fairly certain stop, rather than it slowing, slowing more, slowing a little more etc...

I tried changing the RA agressiveness (from 85 ~ 115 in 5% increments) and also calibration step time (went from 600 ~ 1500 in 100ms increments)

Im lost.. and starting to get rather annoyed with it... The past 4 nights out I've effectively spent between 20 - 28hrs total at the scope, and in that time managed to only get a set of shots on M42 (unguided 4 min exposures) and a set on M45 (again, unguided, 4min subs..)

I pushed it out last night to 6mins unguided, and there was VERY slight trailing in the stars, so the polar alignment is pretty good...

Please help!!

Thanks for any ideas...
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  #2  
Old 20-10-2008, 06:50 PM
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h0ughy (David)
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what about starting it from scratch again once you change from one side to the other - thats what i found i had to do in order for it to lose its memory so to speak. reset evertything back to default and try that. tis all i do - i dont play with much
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  #3  
Old 20-10-2008, 06:59 PM
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At this point mate, I'm happy to try anything...

The irritation is, that it calibrates RA pointing in one direction, but not in the other... Just seems weird to me.

I might also try not running the GPUSB and DBK off the same USB port (via powered hub) I'll try running everything on its own lead and see if that makes a difference.
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  #4  
Old 20-10-2008, 07:06 PM
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the beauty of hand guiding. l'm the only link in the chain so l always know where the problem lies.
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  #5  
Old 20-10-2008, 07:16 PM
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Matty P (Matt)
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What version of PHD are you using Alex?
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  #6  
Old 20-10-2008, 07:34 PM
Dennis
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Hi Alex

Hmm, the worrying thing is one night it works and the next night, it only partially works Ė so what has changed? Here is what I would check:
  • Are the grub screws that clamp/lock the spur gears to the worm shaft tight, or is one loose? (that is, if they are visible like on the Vixen GP mounts).
  • On your GoToís, have you noticed any excessive backlash which may manifest as poor pointing accuracy?
  • Are all the necessary check boxes ticked for correcting in RA and DEC? I havenít looked at PHD for a while so Iím not sure where they are and of their format?
  • Are all cables plugged in fully?
  • Has a continuity test revealed any intermittent connections?
  • Are the clutches tightened firmly so that they do not slip?
Thatís all I can think of at the moment.

Hope you get it fixed mate, I know how frustrating it can beÖ.

Cheers

Dennis
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  #7  
Old 20-10-2008, 07:44 PM
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Alex I had that problem, but only once, where it told my that the star wasn't moving enough for it to calibrate.

This happen when I was imaging close to the pole though, so I suspect that being close to the pole the stars just don't seem to move that much.

Leon
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  #8  
Old 20-10-2008, 08:35 PM
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seeker372011 (Narayan)
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Alex;

I too have an EQ6 and have pretty much the same degree of frustration with autoguiding

IMHO its not PHD thats a problem its the EQ6..PHD works just fine with my CG5

secondly, when it doesnt calibrate in N/S or E/W, the only thing to do is force a recalibration, because it sure as heck isnt going to autoguide. The best thing to try is a longer calibration step-eg go up to 1000 (750 is default in the latest version of PHD, used to be 500 millisecs) or even as high as 1750 some people tell me

(you go longer when you are near the pole,shorter calibration steps when you are pointed far away from the pole)

A guy in cloudy nights suggested that I send the hand guider rate at 1.
Before you say anything- I know-it should not matter!-but I found it does.The oscillations in RA which is where I have trouble were greatly reduced simply by setting the hand guider tracking rate to 1. Makes absolutely no sense.But empirically , it worked with at least two observers--myself and the guy in cloudy nights who suggested it to me

next-watch the calibration routine..if after PHD does its things it has failed to move the guide star in a particular direction-forget it, its not going to guide

this usually means your mount is stuck in some weird backlash, and sometimes I found that that getting out of PHD and just manually moving the mount (I mean with the hand controller)may help
sometimes it means a need to rebalance the mount so it the motors are pulling against the weight

with my old CG5, it needed the last movement to be right and up in the hand controller-go figure-but if you didnt it simply would not autoguide!

I have tried the same with the EQ6 but am not convinced this works witrh the EQ6

I have managed to get the mount to guide several times-for up to two or three hours or longer, and for 10 minute subs at 950 mm focal length--but every time i set up I am not sure its going to work so I am not ready to declare victory

would be interested in your experiences as well
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  #9  
Old 20-10-2008, 08:38 PM
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seeker372011 (Narayan)
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oh I use the GPUSB myself so my set up is not too different-my scope is an ED 127 though
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  #10  
Old 20-10-2008, 09:01 PM
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Thanks for all the ideas guys... I'll get onto checking it all tonight.

Im using PHD v1.9 (latest), and yeah, I cranked the calibration steps up to 1500, I'll go higher tonight..

Ummm.. what else... I tried setting all different settings for the mounts Autoguide speed, from 0.125x through to 1x, In PHD I set Dec guiding mode from Auto to North and to South just to see if it would help, put it back to auto as it made no difference.

Its kind of pushing me towards EQMOD and pulse guiding.
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Old 20-10-2008, 09:08 PM
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Hi Alex,

I use PHD with EQMOD and an EQ6. My imaging scope is a 127mm APO and my guide scope is an ED80 with a QHY5.
I rarely have problems with calibration however it has been a long road to reliability. Note that calibration can be difficult if pointed near the south pole.

First off, make sure the mount is correctly balanced in RA and DEC. I keep RA slightly heavy east, and DEC slightly heavy at the camera end.
I'll attach a screen grab of my PHD setup.

Cheers,

Rob
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  #12  
Old 20-10-2008, 09:18 PM
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Thanks Rob,

all the attempts I made at calibration last night were in the west (fairly high altitude) North (Near Zenith) East (30 degrees up)

In the west it would calibrate RA but not Dec, in the north it would also do RA but not DEC, in the East it would not move the star at all... so I gave up and just imaged unguided...

I did manage to get 40x4min subs of M42, This says to me that the mount is polar aligned well, and that the balance cant be too far wrong.. So its either got to be software or a connection somewhere....
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Old 20-10-2008, 09:23 PM
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Quote:
Originally Posted by AlexN View Post
Thanks Rob,

all the attempts I made at calibration last night were in the west (fairly high altitude) North (Near Zenith) East (30 degrees up)

In the west it would calibrate RA but not Dec, in the north it would also do RA but not DEC, in the East it would not move the star at all... so I gave up and just imaged unguided...

I did manage to get 40x4min subs of M42, This says to me that the mount is polar aligned well, and that the balance cant be too far wrong.. So its either got to be software or a connection somewhere....
I feel your pain!

I switched over to an EQ6 recently and use GPUSB - it certainly doesn't like the USB hub I use (the lappy has only 2 USB ports which aren't enough for mount, guidescope and 2 cables to the Canon).

I found a few restarts of the laptop, AC power to the computer and long calibration finally made it do its thing.

Good luck

Pete
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Old 20-10-2008, 09:28 PM
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[1ponders] (Paul)
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Don't worry Alex. We'll get you sorted out at Ron's. That's what they pay me the big bucks for. It is frustrating though. When you come up we'll make a new cable and see if that sorts it out. I've lost count of how many times issues have ended up being a cable problem.


Also if you are using a HUB. GET RID OF IT! I had nothing but problems with my GPUSB when using through a hub, especially if the guide camera was going through the same hub
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Old 20-10-2008, 09:31 PM
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Quote:
Originally Posted by AlexN View Post
I did manage to get 40x4min subs of M42, This says to me that the mount is polar aligned well, and that the balance cant be too far wrong.. So its either got to be software or a connection somewhere....
Yes, it could be a connection or wiring polarity issue. I guess you're using ST4 guiding? I've never used the ST4 port so I can't help you there. With EQMOD I use ASCOM pulseguide which allows many adjustments and tweaks on-the-fly. I was originally forced to use ASCOM Pulseguide because I didn't have an ST4 cable, but now I won't use anything else.
Cheers,

Rob
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Old 20-10-2008, 09:46 PM
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I have no idea what the answer is, Alex, but on a separate note there's a nice little article on 'Guiding on a Budget' by Alan Dyer in the Nov/Dec issue of AS&T.

The focus is on the Orion StarShoot camera, but there's also some info on PHD in there.
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  #17  
Old 20-10-2008, 09:49 PM
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Quote:
Originally Posted by [1ponders] View Post
Also if you are using a HUB. GET RID OF IT! I had nothing but problems with my GPUSB when using through a hub, especially if the guide camera was going through the same hub
Cheers mate

I thought to myself last night, Oh well... Its only a few more days and I can annoy Paul with my problems

I'll give it a run tonight without the hub, and see how that goes... Hopefully that will sort it out...


I'll check the cables tonight for any dirt/dust accumulation on the connections, also inside the ST4 port on the mount...
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  #18  
Old 20-10-2008, 10:21 PM
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multiweb (Marc)
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Hi Alex, I understand your frustration. I've had my share of troubles with PHD. Like any other software it behaves erraticaly at times. When this happens, the best thing to do is to shut it down. Unplug your guider (USB) then replug it in. Start PHD. Go to the brain button and go for 2000 or even 2500 for your calibration steps. The star will take only 2-3 moves to get out of the 25px range. If nothing seems to work and you have changed your calibration steps you'll find that PHD still won't work until you shut it down, unplug the guider, plug it back, start PHD again. Then it calibrates and the mount moves as if nothing happened. I pulled my hair over this so many times I'm not trying to make any sense of it. Anything that is plugged into a USB port sometimes loses it and the software associated start behaving badly. Sometimes stopping the current exposure on my imaging cam would screw up PHD because it is plugged into the same USB hub to the laptop. So these connections seem to affect each other somehow. Hope this helps.
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Old 20-10-2008, 10:47 PM
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Tandum (Robin)
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God, sounds a lot like what mine was doing at barambah doesn't it. You could try what we did there, park the mongrel, go get a drink, have a smoke and it will be working when you come back to it
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