QHY5 and PHD guiding problem

[Roy@Aldermaston]

I've just bought a QHY5 guide camera, which I'm using along with PHD to guide my NEQ6 mount via the ST4 port. Despite trying various settings PHD is refusing to clear the DEC backlash and guide in DEC, and so I tried the manual guide controls to check communication between the software and mount. When pressing east, west and south buttons I can hear the motors respond, but there's no sound from the motor when pressing the north button. I have checked the continuity of the ST4 cable with a multimeter and it was OK. Has anyone else had problems like this - could it be the plugs, or is it likely to a problem with the mount or QHY5 connectors? Any ideas what diagnostic checks to try next?

[Merlin66]

Are you 100% sure you're using a straight through ST-4 cable??

The attached Shoestring note gives details..

guide_port_cables.pdf

[Roy@Aldermaston]

I will check, but the ST4 cable was supplied with the camera by Modern Astronomy.

[Merlin66]

It should be OK then.

Just check the pins in the connectors on the mount and the camera.

Do you have any other guide software you can try? AA5?

[Uranium235]

Check there is no muck or dirt in the ST4 sockets, my QHY5 has done that a couple of times too. I just gave it a blow and a wipe and it was fine after that. Might also be worth checking to see if any pins are missing or bent.

[Roy@Aldermaston]

The plugs and sockets seem OK, and I've checked the mount motherboard for dry solder joints.

[Merlin66]

Hmm

Is there a chance you have reversed the Dec with the RA settings in PHD??

I dawned on me that there's no motor movement when you press West (?) - the motor just switches off and the siderial rotation causes the movement.

So you should hear the motors for North/ South/ East but no West....

[Roy@Aldermaston]

Sorry, I don't quite understand - the lack of motor movement is in the north axis, not the west.

[Merlin66]

yes, but if you have the axis orientation(s) reversed in PHD, then what you think is the North may actually be the West.....

Does that make any sense???

[Roy@Aldermaston]

Yes it does, I suppose it could have happened when I was tinkering with the various settings, but how do I check. I have no idea where to find the setting.

[Merlin66]

I'd check the mount first - handcontroller directions - do they match the sky?

In PHD you can reverse the calibration (tools)

Also make sure the dec control is set to Auto.

Can't think of anything else.....

[Roy@Aldermaston]

Hand controller directions do match the sky. I've decided to send the camera back to the supplier to get it checked out. If no fault is found I'll try the PHD settings.

Thanks for the help.

[Merlin66]

Roy,

I'd be interested to hear the final outcome...keep us informed.

[Roy@Aldermaston]

Will do, once the issue is resolved I'll post the outcome.

[Roy@Aldermaston]

An Update

Had my camera back from the supplier who claims that it tested OK, but the problem persists so I've experimented with PHD settings and found a work around.

I let the program run through RA calibration and when it stalls on clearing DEC backlash I use the handset to nudge the scope to the south and then north. It then starts to calibrate North but won't complete, so the dodge is to turn off DEC calibration and let in run in RA for a short time before resetting DEC calibration to auto. That immediately starts the DEC calibration and from then on I get a tight graph and good guiding.

I've no idea what's going on, but it works.

[martin_h]

It looks as if you have a lot of dec backlash - I do as well - I centre the target in the imaging scope, then move it north then back to centre in south this gets rid of the backlash for me. Then run PHD calibration, and it clears the dec backlash in a second or two.

If North to South doesnt work try South to North...it depends on where the scope settles on the target after a goto.

[Roy@Aldermaston]

That's pretty much what I have been doing, but the mystery is why turning off DEC calibration (or allowing PHD to turn it off after it fails to calibrate in DEC) and then turning it back to auto allows it to guide in both RA and DEC. Its a work around that seems to produced reliable results and allows me to guide for several hours without any further problems..

[dmahon]

Do you connect your computer to the scope with EQMOD as well*, or do you use the handset?

If you use EQMOD, try using EQMOD to issue the guide commands (change "on-camera" in PHD to EQ6). You don't need an ST4 cable attached (or port) for that.

If the problem is DEC backlash, you would expect the problem to continue with pulse guiding. If the problems is something to do with the cable or connectors, then pulse guiding with EQMOD will cure it.

* if not, why not - it beats the hell out of the handset.

[Roy@Aldermaston]

Here's an update on my guiding problem: I eventually narrowed it down to a faulty DEC+ relay in the camera, and after a fairly heated exchange managed to get a refund. I have since purchased another QHY5, which appears to be working fine and in between the cloud and rain I have been able to achieve up to 900 sec exposures. Thanks for all the helpful suggestions.

Roy

[sloz1664]

Roy I take my hat off to you. I have been following this thread closely and can understand your frustration as the initial problem could have been, software, mount or camera.

having found the problem you have then to convince the supplier of the QHY5, his camera is at fault. I am glad it's all behind you and hope the skies clear so you can

guide to your hearts content. I have no regrets with my QHY5 and would happily replace it with the same if needs be.

Steve

[Roy@Aldermaston]

Thanks Steve,

It's a great relief to have been vindicated, I'd almost reached the point of giving up.

Roy

[The Sailor]

Been following this thread as well and am glad it got sorted, will be using my QHY5 for the first time as soon as we have a clear night, fingers crossed .

Jim

[Coco]

Interesting stuff, tonight I spent 4 hours messing about and have finally given up, new ST4 cable ordered, failing that a new QHY5

[Thalestris24]

Interesting stuff, tonight I spent 4 hours messing about and have finally given up, new ST4 cable ordered, failing that a new QHY5

Oh dear - what's the problem? Don't forget that you have select 'on camera' for the mount if you use ST4...

Louise

[Coco]

Oh dear - what's the problem? Don't forget that you have select 'on camera' for the mount if you use ST4...

Louise

Thanks for reminding me Louise, after 6 years imaging I think I can remember that one, although forgetting to tick the capture and save image  slips past me now and again