Guiding settings/diagnosing problem

[Beanix_Rising (Jacqui)]

Hi all
I watched a YouTube video about how to improve guiding and followed all the suggestions and ended up getting the worst guiding results I’ve ever had! I tried to change all the settings back to how they were prior to watching the video. For the most part I’ve got back but I am now seeing a weird spike in RA which seems like it is a repeating pattern. The guiding will sit around .5” Total RMS for a minute or 2 then a have a series of spikes in RA, then it returns to .5” total RMS for another minute or 2. And it does this for the whole session, I’ve tried tweaking settings but haven’t been able to find the issue. It never behaved like this before I changed the settings as per the video. I’ve googled looking for a fix but I can’t seem to find anyone who has had the same issue to know what settings might be causing this. I’ve attached a couple of guiding graphs where it travels along fine then starts to spike. Any suggestions greatly appreciated. TIA

[AstroViking (Steve)]

Hi Jacqui,

First off, welcome to IIS!

First question - what guiding software are you using? The screenshot looks like either PHD2 or the ASIAir's interface.

If it's PHD2, (which I don't use, so only guessing here) is there a 'reset configuration' option to get you back to a clean starting point? Failing that, uninstalling the program and removing all of it's files then re-installing is a brutal solution...

If it's the ASIAir, is a factory reset out of the option?

The next obvious question - have you made any changes to the cables on the mount? It's possible there's a cable snagging on something.

Cheers,
V.

[Beanix_Rising (Jacqui)]

Hi Steve Thank you for your reply…I’m using Asiair+
My cable are not snagging, and no changes made to the actual set up - just the settings when I followed the video. I did receive feedback on another forum suggesting perhaps my balance is out, and also the aggression looks too high. The next clear night will look at balancing east heavy as I had a neutral balance on this session…if that doesn’t address the issue I think a factory reset probably is a good idea…start with a clean slate. I have learnt a valuable lesson in that I should take screenshots of my settings before making big changes in future. Cheers J

[iborg (Philip)]

Hi Jacqui


Keeping a copy of your settings before fiddling is always a good idea. One day I might actually do it!


Having said that, does the ASIair have an export configuration option?


Doing this, then bringing the same file back would be a good way of keeping a record and reverting if you need to.


Philip

[Rusty2]

Hi Jacqui !

I have the ASIair program and pulled my hair out for over a year trying to get my RA behaving . Those pictures , to me , look like a balance issue or backlash . Have you checked your backlash ? While your entire rig is locked , try and wiggle the scope on both axis . If there is any tiny movement it needs to be dealt with .

If it was me I wouldn't touch the program settings just yet .

I keep my rig slightly bottom heavy . Telescope slightly front heavy .

Good luck : )

[Beanix_Rising (Jacqui)]

Thanks Rusty no movement in either of the axis when the clutches are locked, I had the mount serviced earlier this year and had a rowan belt mod completed. Only got a little imaging in after the mod before winter and spring brought never ending cloud cover, but it was tracking smoothly back then. I think my balancing could do with some more work, hopefully will get some clear skies soon when I’m not working to see how I go!

[Beanix_Rising (Jacqui)]

Cheers Phillip I’ll look into confit export and certainly use it in future if it exists 👍

[AlexN]

This certainly looks like a mechanical issue to me.

It's the exact same size 'bump' every time it happens. I'd say you have a bit of metal swarf in the ra worm/wheel that's working its way into the gears...

I don't know how the asiair works, can you see the corrections on the graph at all? As in, you can see the graph, but every time the software makes a correction in phd2, there is an associated 'correction' bar on the graph. This would show you at least if it was sending the mount astray, then bringing it back.. But like I said, this looks very much like a mechanical issue to me... the bump is so uniform every time it happens, its just a matter of figuring out what the frequency of it is, then mapping that to worm rotations, motor drive wheel rotations or tension pulley rotations etc. Something will be catching somewhere or dragging somewhere in the gears or belts... it's too perfect to be anything software related.

[Leo.G (Leo)]

Originally Posted by AlexN

It's the exact same size 'bump' every time it happens. I'd say you have a bit of metal swarf in the ra worm/wheel that's working its way into the gears...

My mount is only a cheaper Skywatcher EQ5 Pro GOTO unit (purchased used) which has been heavily modified by myself with the assistance of an engineering friend who did the required machining. When I stripped it down to modify it I was shocked to find not only a small amount of swarf in the internals but also poorly machined surface finish on the internal gear and housing which is aluminium in my mount, brass in the dearer HEQ5. It would basically lock up at the same point every rotation and it took a while to find it had the smallest protrusion/bump which I was quick to reduce with some fine wet and dry paper. It made a HUGE difference to the performance of the mount, as did changing the standard roller bearing for a tapered roller which works with a load better in the axes.


In saying this I don't use guiding software as of yet because I don't have a good system/placement and PA, it's just rough on the night and I only usually do short exposures depending on drift on the night.


I didn't see which mount you have but I'm assuming it's a higher spec/quality unit than mine but these things are mass produced and while I'm sure they turn out some fine examples I believe they turn out many which didn't go through proper QC testing.
I do know from experience in certain industries QC was pull 1 item out of every 1,000 and check it (other than a very rough visual glance on the assembly line pre packaging) and that 1 unit out of the 1,000 we knew was going down the production line and were sure to put every nice touch on the unit. This was in Australia in the 70s and 80s.


Good luck!

[ChrisV (Chris)]

I use phd2. Anyway, given my ignorance of asiair, I vote for potential grit as below. Also polar alignment could be improved - your trace is not centered over zero, so always fighting to centre the star.

But very hard to be certain as trace is low resolution and can't see the guiding pulses. Log files always help