IEQ45 Pro and PHD2 OAG Guiding issues

[waylander]

Ill try that - actually i do get binding sometimes so i reckon mine needs backing off a bit. How to adjust the allen head screws though? You mean the ones where the belt is?

 

 

[Davey-T]

You don't need to adjust those just make sure they haven't worked loose, you have to remove the belt and pulley to tighten them.

Dave

[waylander]

A question on this then. What signs in my guiding am I looking for which will tell me my mount needs adjusting? My ra binds occasionally and guiding has always been worse on the axis with random spikes too. 
 

how much deflection should the belt have? Ie how can I tell if it does need adjusting tightening whatever?

Edited April 7, 2020 by waylander

[michael8554]

Looked at your Guidelog.

Are you clearing Dec Backlash before Cal by nudging north until you see the star move ?

That could stop the error messages.

Yes should be better with 0.9 Guiderate and new Cal.

Polar Alignment is good so Dec should only require minimal correction, particularly if you have balanced slightly heavy one way.

Maybe keep the recommended high MinMo and reduce Aggr to 70 % to reduce the unwanted back and forth moves in Dec.

Saw you playing with PPEC settings which is fine, but next time at 0.9 Guiderate let it run a goodly time on the default settings before playing.

Getting there !

Michael

 

[waylander]

Hi Michael. I did offset the balance a little, but noticed that due to updating the firmware on the handset it reverted my 0.9x guide rate... didn’t check it. 
 

no I didn’t get chance to run north for a while to take up the backlash. Honestly I spent a lot of time just trying to find stars at dec 0 in the clouds! For such a clear night they knew where to cause maximum damage. 
 

and yeah. Trying to resist fiddling too much with settings! Once I get a clear night next week away from the full moon I’ll try focus properly (hard!) and redo everything again. I’ve got a good feeling about this. 
 

Thanks again, I’ll post a pic on here to show my progress once I get better skies. 

[michael8554]

Nudging North only takes a few seconds with the handset on lowest slew, looking for movement of the star on the PHD2 screen. 

Or using the PHD2 Manual Move in Tools menu with a large setting, say 5000.

Michael 

[waylander]

My mental load was at Max though. Lots of things to remember! 

[waylander]

Went out last night and tried again to get better guiding. Moved both axes to 0.9x guide rate to sort backlash, which proved effective.

Calibration went better, seeing was better so lots of stars.

Guiding was generally very good in DEC (0.3-0.6" ish) but worse in RA all night (1-1.2"). I feel i understand the DEC axis now, but RA is another thing entirely. I noticed i do have some binding at one point in the RA rotation, so im gonna very slightly slacken off the RA rocker adjustment screw (like 1/32 of a turn). Perhaps that could also be causing too much friction in RA generally too?

Warned to improve guide star focusing, which may be fair, so gonna buy a helical focuser for the OAG. However - with regards to the RA i just cannot get it to settle down, i've tried high agg, low agg, high minmo, low minmo. So im gonna try and set that axis to a lower guide rate, it could be it just needs less "work" to keep it in the green. So gonna go for 0.3x on RA next outing and keep DEC at 0.9.

Any thoughts, let me know!

Have attached logs.

PHD2_GuideLog_2020-04-11_204631.txt

[michael8554]

Here's RA:

 

I think I see the RA binding you mentioned.

The red arrow points to the MinMo setting - I still haven't seen any sign of a Guide Assistant run, so you're guiding blind.

Here's Dec:

 

 

Same vertical axis scale as RA, guiding is twice as good, except for the big up then down episodes.

Left to itself Dec would probably chug along at 0.5 arcsecs, which would be good in itself, but there's that MinMove again that sends it off northwards, Dec Backlash takes ages to clear, so it careers down south etc etc.

Try a higher Dec MinMo.

Michael

 

 

 

 

[waylander]

I was kind of happy with the dec to be honest! Do you think reducing the guide rate for R.A. will help at all? The R.A. was the thing that most concerned me as any changes seem to aggressive and cause a bounce. Thought if I reduced the R.A. guide rate and hence hopefully reduced the effect of any changes it might settle down a bit.   I’ll make the slight change mentioned to the R.A. end cap too.  Forgot to do a ga run... didn’t do one till the end of the night just to see what it said. 

Edited April 12, 2020 by waylander

[waylander]

Ga didn’t recommend to turn on backlash compensation so I’m assuming it didn’t think that was bad enough to mention?

[waylander]

It just recommended 20 minmo for R.A. and 30 for dec. didn’t seem right to me.  
 

oh one other thing... I don’t level my mount at all... should that matter?

Edited April 12, 2020 by waylander

[michael8554]

1 hour ago, waylander said:

Do you think reducing the guide rate for R.A. will help at all? The R.A. was the thing that most concerned me as any changes seem to aggressive and cause a bounce.

No. Giving PHD2 the ability to make big corrections can quickly correct any large guide errors that come along.

PHD2 will still be able to make small moves when needed.

So more a case of Aggression and MinMo settings - after you've adjusted the RA worm.

1 hour ago, waylander said:

I was kind of happy with the dec to be honest!

With those 2 arcsec spikes ??

1 hour ago, waylander said:

oh one other thing... I don’t level my mount at all... should that matter?

The source of endless argument on this site !

Not necessary they say because the Alt and Az adjustments for PA take care of any error in level.

But roughly level prevents Alt and Az adjustments interfering with each other.

That's my opinion and I'm sticking to it......

Michael

[waylander]

Right tomorrow night I’ll do this again. I’ll adjust the worm and try bigger minmo and lower aggression for both axes. 

[michael8554]

41 minutes ago, waylander said:

I’ll adjust the worm and try bigger minmo and lower aggression for both axes. 

After accepting the Guide Assistant recommendations and guiding for long enough to see how they work !

Michael

[waylander]

Yes boss

[waylander]

Noticed that my RA balance was very very out - like the counterweight was 1/3 of the way on the countershaft (3 inches?) out according to the handsets auto balance routine. That could have contributed to the rubbish RA...

Edited April 14, 2020 by waylander

[waylander]

Have just been back over old guide logs and have seen a few examples of great guiding in RA (like 0.5-0.6") for long periods so looks like the mount is capable of it if set up by a competent person.