Guiding error update

[leon]

Hi Guys here is an image of what happens when my guiding started to play up, can anyone detect from the odd star trails what could have caused this. :shrug:

Leon :thumbsup:

[[1ponders]]

Jeez Leon, you haven't swapped the DEC and RA cables around accidentally have you. :shrug:

[leon]

No Paul nothing has been changed, but something is certainly not happy, when I get a chance I will give the whole set up a good service, connections, lube, the lot.

Leon

[Dennis]

Hmm, looks quite strange. The first thing I would do, is check all nuts, bolts and grub screws that fasten drive gears to shafts and worms etc, to make sure that one hasn’t slightly worked loose and is allowing a gear to slip on a shaft in an ad hoc manner.

Cheers

Dennis

[Jeffkop]

Hi Leon

Im no G11 expert, however experience in my proffesion has taught me that when ever you have a closed loop type system that fails, you have to open the loop and fault find from there. In this instance stevie wonder could tell you that the guiding is stuffed. A simple way of isolating it to either mechanical or electronic could be unplug the auto guiding and see what the mount comes up with by itself over a minute or two. You may find that the guiding is not perfect but it definitely is somewhat better in a way, and you may not. The only experience I have had with images that look like this was a mount that had faulty electronic operation. The tracking would be ok until the system started making huger error corrections to try and get the guide star back.

If you get an identical result then you probably needn't look at the error correction side.

Hope this helps.

[leon]

Hmmm, thank you Jeff, excellent idea, the steps of elimination, sounds like the way to go.

Leon

[TheDecepticon]

Hi Leon,
It really looks like it is wind affected. I've seen it before and it looks very similar to this.
Cheers,
Gray.

[leon]

Thanks Gary, I would discount that with this particular imaging run as it was pretty quite on the night, and I have imaged in windy conditions before.

Thanks for your response however.

Leon

[scopemankit]

an earth tremor or traffic vibration?

[gbeal]

Wild guiding if you ask me. And in two axes as well, not just "no guiding" so elongated stars, but a bit of both. What is the guide camera Leon? While it is possibly not in your case, some guide (or think they are) on a hot pixel.
Guide-scope not loose?
Gary

[DavidU]

I thought I was seeing an earth tremor while looking at Jupiter the other night until I noticed the cat rubbing against the EQ5 mount LOL.

I hope you can sort this one out Leon.Must be frustrating.

[gbeal]

Ah, yes, the cat attack, I'll second that Leon, not got a Moggy that likes your pier? Mine wrecks the occasional image.
Gary

[leon]

Frustrating is right, and more so now that it is wet and cloudy so I can't even get out there and try and fix it.

Gary, it is very weird indeed, but i feel it will have a simple explanation, I hope.

Gary I use the Orion StarShoot, and it has performed perfectly until now.

Leon

[White Rabbit]

I've had similar results when i first starte guiding and it turned out to be the settings I had in PHd. Might not be your problem but that what it was for me. check that you havent changed any settings by mistake.

[leon]

Yep I will have a look at the Mr Rabbit. ;)

Leon :thumbsup:

[multiweb]

What FL was this sub taken at and what was the exposure time?

[leinad]

Looks like PHD lost the guide star temporarily and then corrected for it?
Thats quite a shift in position though, and the drift would have been bad to move that much.
Guidescope secured correctly? Guiderings not tight enough ?

[multiweb]

Leon, the best thing about the G11 is its modular design. It's like LEGO blocks. You can pull it apart in 5min and put it back together in 10. If you've never opened it then the most likely culprit is clutch slippage. The nylon discs get greasy over time. The grease will come from the bearings, mostly in RA. You don't even have to take the worms out to rectify this. Unscrew the knob at the end of each axis and take off the thrust bearings at the end of each shaft and slide off the axis. You'll see the discs. Give them a good clean with a rag and alcohol if necessary and try again, see if it makes things better. I actually glued mine on the bearing side with rubber Gel Grip to get higher break away friction. :thumbsup:

[Geoff45]

Leon
Are you using PHD? There has been a bit of a thread on the Stark labs website about people's guiding going off for no apparent reason.
Geoff

[multiweb]

Yeah I've noticed that for the past couple of months. Loads of heated discussions about it. Since the 1.10.x batch of PHD was released. I have also noticed PHD is a bit more aggressive in RA and "slacker" in correcting DEC with the default settings but tweaking the parameters fixed all that. Most of guiding errors were mechanical or balancing on my end, not the software. Have you had issues with the GM8 and PHD?

[Paul Haese]

My first thoughts were that this is a loss of guide star. I got several images like that last weekend when guiding was interrupted by cloud.

I reckon check the parameter in PHD. Then check the mount from top to bottom, just quickly at first. Check your cable connections. They can get dirty and stop working. Obviously check for loose items.

As suggested do an unguided then try guiding, that will soon identify mechanical over electronic. Is the guide cable in the correct place? Did you break down your mount to go to SV? If so, are the cables right?

Best of luck with your search, yes I know how frustrating things can get.

[Geoff45]

Yes. Not so bad as to ruin the pics, but bad enough to take the edge off them. As soon as the weather clears I'll try using Maxim and see if it makes a difference.

[multiweb]

Have you tried drift aligning and do 1min unguided subs to rule out any mechanical issues?