Another EQ8

[Zakalwe]

Maybe I'm off the norm with mine but I've had a lovely flat PHD graph, Maxim reports my stars as being 0.01 out of round (best I have ever seen) ... I honestly don't feel the need to analyse the PE and worry myself

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Hi Stephen,

I'm curious about the performance of mine and am keen to learn about PE and PEC.

Certainly (well, the single chance that I've had to do any DSO imaging) I have been impressed with the smoothness oh the PHD guiding (I progressively knocked the RA Aggressiveness setting down from what was required on my EQ6). Hence my interest in the process.

[sloz1664]

Maybe I'm off the norm with mine but I've had a lovely flat PHD graph, Maxim reports my stars as being 0.01 out of round (best I have ever seen) ... I honestly don't feel the need to analyse the PE and worry myself

 

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Hi Stephen,

Glad to see you've got the EQ8 up and running, the Maxim specs look really good too.

Steve

[Stephen]

Hi Stephen, i have to agree with the sentiment, it's the shape and outcome of the image  that matters, however for some..it's also the knowledge and practical benefit of knowing  that a mount meets the expectations put on it otherwise there would be no use in having the software to measure such things.

Ray

Ray 

Fair play

Hi Stephen,

I'm curious about the performance of mine and am keen to learn about PE and PEC.

Certainly (well, the single chance that I've had to do any DSO imaging) I have been impressed with the smoothness oh the PHD guiding (I progressively knocked the RA Aggressiveness setting down from what was required on my EQ6). Hence my interest in the process.

Look forward to seeing what your results come out like

[ollypenrice]

Hey, if it works it works. Who's complaing?

Olly

Sorry, or even 'complaining...'

[Zakalwe]

I've re-done the PE analysis correctly this time, by disabling the PHD guiding output.

This is what the PE analysis looks like:

And the resulting PEC curve:

Am currently trying to record a PEC in EQMOD but rolling clouds keep blocking the guide star

I need to redo the polar alignment as it was drifting in DEC (assuming I can be bothered as it guides out OK)

[pragmatist]

That is a beast.

[Zakalwe]

I've re-aligned the mount, this time using the 428EX camera on the Equinox. Using crosshairs (in Neb) will give a lot more accuracy. A few iterations of the Synscan polar alignment routine has the polar alignment error down to a handful of arc-seconds. I've then had a bash at fine-tuning the PHD setttings as the aggressiveness was still too high. I think that it's somewhere near now.

This is now the unguided graph (PEC correction not enabled in EQASCOM)

I've run the PHD data through PECPrep again. This result looks too good...I must be making an error somewhere???

The guide star is at 15 degrees Declination. Guide output is disabled in the PHD brain. QHY5 on OAG. Equinox 80 scops, TRF2008 focal reducer. Focal length is 400mm f5.

When I apply PEC correction in EQASCOM, then I get this:

Which looks to be a bit more like it?

Dunno what I am doing wrong in the first PECPrep session. I simply don't have the experience or knowledge to fathom it out.

Either which ways, this mount appears to be performing beautifully. I am very very pleased with it.

[Zakalwe]

And here's the guiding graph now:

[libraryman]

Hi, the smoothed data does not look good really, it might be time to ignore the PE results and accept the guiding performance unless of course you are just enjoying the learning curve of PE data.

i have attached my PE results again.

Give PHD2 a bash, it will give you the guiding in Arc sec as well as an improved interface, 0.14 RMS is quite good though,

i use guide rate 0.75 on RA & 0.25 on Dec, I'll give 0.25 on RA  a try myself

Ray

EQ 8 PE error.doc

[1parsec]

It's difficult to compare the 2 PE curves as there is different filtering levels set in PecPrep. Simon has 0 high pass and Ray 221 which reduces the displayed Peak PE+  Peak PE- values.

The Y axis is plotted to different scales too .  

I think selecting the blue raw trends or use similar filtering would make a clearer comparison ??

Dave.

[Zakalwe]

Hi, the smoothed data does not look good really, it might be time to ignore the PE results and accept the guiding performance unless of course you are just enjoying the learning curve of PE data.

i have attached my PE results again.

Give PHD2 a bash, it will give you the guiding in Arc sec as well as an improved interface, 0.14 RMS is quite good though,

i use guide rate 0.75 on RA & 0.25 on Dec, I'll give 0.25 on RA  a try myself

Ray

I'm enjoying learning about PE.

Plus, I recorded the data when I was tweaking the PHD settings, which might have affected things.

[libraryman]

It's difficult to compare the 2 PE curves as there is different filtering levels set in PecPrep. Simon has 0 high pass and Ray 221 which reduces the displayed Peak PE+  Peak PE- values.

The Y axis is plotted to different scales too .  

I think selecting the blue raw trends or use similar filtering would make a clearer comparison ??

Dave.

That's fair comment, i would not say that my PE is "the" representative  of an eq8's performance, it's just that i was happy with the result i achieved and it fit very well with what i believe  Skywatcher predicted for the mount,  an AP 1200 is expected to achieve <or= to 4 arc sec peak to peak (if i understand it correctly) but you will pay more that double the price of an EQ8 so i think that 5 or so arc sec from an EQ8 is very good indeed.

Of course i am happy to be proven incorrect

Ray  

[Astroscot2]

Hello,  So far the skies here have cleared for a while to allow me to do some polar alignment, guiding is next on the list. Can I just ask other EQ8 users whether their mounts produce a high pitch ring when tracking? Also at the end of my goto's I also get a low growl as the mount 

approaches the object. Ive heard users say their EQ8s are silent when tracking ? have come from an Losmandy G11 which was silent I fear my EQ8 is going to wake up the neighbours !!   Will a firmware update cure the noise issue?

Thanks

[Zakalwe]

Hello,  So far the skies here have cleared for a while to allow me to do some polar alignment, guiding is next on the list. Can I just ask other EQ8 users whether their mounts produce a high pitch ring when tracking? Also at the end of my goto's I also get a low growl as the mount 

approaches the object. Ive heard users say their EQ8s are silent when tracking ? have come from an Losmandy G11 which was silent I fear my EQ8 is going to wake up the neighbours !!   Will a firmware update cure the noise issue?

Thanks

You can't hear mine tracking over the racket that the Atik camera makes. If you listen for it, you can hear the motor noise change if the guiding issues a command.

[Astroscot2]

Hello Stephen, the high pitch ring is tracking only no guiding,  what about your slews any odd noise as the mount makes final adjustments on the approach?

Thanks

Mark

[Zakalwe]

Mark,

It's gotten quieter since I first got it, to be honest. At first it made a bit of an odd sound on high speed slews in DEC..a bit like something rubbing on the main wheel? It seems to have settled down...probably everything bedding in.

As long as it tracks and guides OK then I wouldn't be too worried about it.

[Astroscot2]

Thanks Stephen

[stephen_usher]

You hear the whine of the stepper motors running at high speed, but it's not loud. As you get close to the object it slows down, so the pitch decreases.

The mount is quieter than my previous mount, a Celestron CGEM.

[Astroscot2]

Hello,  Its not the slewing , its general tracking, there is a high pitch ring/ hum continually from the mount, its certinally not quiet when tracking (im not talking about guiding here)    also at the end of a slew there is a louder low pitch growl before the beep confirmation.

How does yours sound ?

[Stephen]

Hello,  Its not the slewing , its general tracking, there is a high pitch ring/ hum continually from the mount, its certinally not quiet when tracking (im not talking about guiding here)    also at the end of a slew there is a louder low pitch growl before the beep confirmation.

How does yours sound ?

I don't think it was as bad as yours but there was a bit of a hum from mine when it first arrived - I did however apply the 2.09_LP Motor Controller Firmware and it's as quiet as a mouse now whilst tracking

[Astroscot2]

Ah, thanks fo that

Mark

[stephen_usher]

It also depends upon the quality of your power supply.

I know that when I turn my mount on I can hear a mains hum coming from the motors, which dies down quickly as the power supply warms up. (I think I need a better (cleaner) and more powerful 12 volt power supply.)

[tony210]

Hi- my EQ8 tended to grunt at the end of slewing and slews are noisy but tracking is quiet - like Ray I have had a go at adjusting DEC backlash but was a bit disappointed as the crucial top plate with slugs for adjustment seems to have glued bolts that will not shift so I was forced to use rocking to find the tight point to tighten- I have the 3  slugs on the top plate to adjust DEC - hopefully it will be better now with PHD as there was a DEC issue I am sure during the PHD setup -anyway an evolving story- waiting for a clear night to test out and will post PHD graphs if useful - Tony

[Astroscot2]

Tony is your mount still noisy after the dec adjustment?

[libraryman]

Hi Tony, just to clarify; the cover i refer to is the plastic cover on the dec housing, if you remove it you will see the coupling that you can turn with your finger and thumb.

don't try to remove the top plate with the 3 grub screws in it!

Ray