slow computer. Is this the cause of mountain peaks guiding graph?

[Jon Clarke]

What effect would a slow computer have on guiding and what is the best work around?. Its not normally slow but having three or four applications running may contribute to the problem. 

[Brian Valente]

Hi Jon

What makes you think this is an issue for your guiding and not something else?  

"slow computer" is a relative thing so I don't think i can give you feedback with that little amount of data. Generally phd does not require much resources or computing power to work, but if you are pegging your cpu with other processes, that could cause issues. 

Uploading your guidelog and debug file would certainly help here by following these instructions;

https://openphdguiding.org/getting-help/

On Thu, Jan 19, 2023 at 10:54 AM Jon Clarke <clarke...@gmail.com> wrote:

What effect would a slow computer have on guiding and what is the best work around?. Its not normally slow but having three or four applications running may contribute to the problem. 

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[Jon Clarke]

I'm still getting very slow mount responses with my N/S pulses and did some star cross tests to find out what was going on. I understand now that this might be a backlash problem rather than a slow computer problem. The star test works fine E/W but takes between 8 -12 steps to start moving N/S and 10 to start resetting to original position. (at least that is what appears on my wifi remotely connected computer but is possibly got a time-lag anyhow) I have done some work on tightening up play on my RA drive and it seems immediately responsive when i turn the cog. I have also noticed south corrections take for ever to happen when doing the guiding assistant secondary test (after the 2 minute test). I have learnt to put smaller figures  in "calibration steps" which should give the mount a chance to catch up. Anyway i include my logs (ignore middle part that clouded over and see either ends. The star test are included but I couldn't get an image of the N/S movement even though i saw the movement on the screen it didn't appear in the photo for some reason See photos 

I thank you for helping me in advance 

Jon

[Brian Valente]

Hi Jon

What type of mount is this?

It seems like a real mess here. 

Why are you binning your camera when it's already a pretty coarse image scale? I suggest you create a new profile via wizard and stick with bin 1 unless you have a specific reason not to.

Why are you using a device hub for your camera? it seems like added complications, not sure what is the benefit

Each guiding run appears to have different issues than the last one, but let's look at the one you did immediately after a reasonable calibration:

1. i agree your dec backlash appears to be an issue, but you have pretty bad polar alignment which is causing a lot of issues here. 

Your guiding assistant run gave you a warning on this as well as the dec backlash. It's a good idea to review your 

For Dec backlash, enable auto backlash compensation, set the value to around 1200 and max 2500. It will be a start to see if you can tame this. But again, you won't 

Finally it appears you have something mechanically wrong or possibly cables snagging on your dec: you can see it make a massive >30" move without any reason, indicating something instantly shifted. That's something you should track down. There are other examples as well of this. 

To view this discussion on the web visit https://groups.google.com/d/msgid/open-phd-guiding/b60458ae-4dd8-40b1-a334-0e911f2a428fn%40googlegroups.com.

[Jon Clarke]

I have a Vixen GP Mount and a QHY5 guide camera on a 300 x 50 mm guide scope. PHD will not recognise it as a QHY camera and I cannot find the WDM driver so that's why i use Ascom and 2x binning which i think produces a darker image

Re setting up correctly:   i have always assumed is 5.2 pixels but maybe im getting confused with um

 See Spec 

• Sensor Mitron MT9M001, 1/2 inch, BW
• Effective Pixel: 1280x1024 1.3Mpixels
• Pixel Size 5.2µm x 5.2µm
• Peak QE 56%
• USB2.0
• 40 fps (with 400x400 ROI and 26 ms exp. time, can vary for other settings)
• Uncompressed Video data
• Built in Guide Port (standard 6 pin RJ12)
• Mechanical interface M42x0.75 (T2)
• Filter interface M28.5x0.5 Screw
• Size 64mm diam x 33mm high
• Weight 100 g
• 
  
• I will check pin out on to see if I have soldered everything correctly on the 8pin sockets 
• Could the >30 degree move simply be the scope hitting the mount? 
• Could you comment on the star cross test which didnt show N/S movement in the photo but did move eventually on the PHD screen. It was odd that each image changed direction 
• I have enabled backlash compensation with the figures you suggested
• When i have large RA movements was I wrong to lower the RA aggression number in last session? 
• Got a few days before clear skies to tweak settings if you can give some more help
• thanks Jon

[Jon Clarke]

I think i have a problem with backlash setting. South corrections are always bad particularly in the backlash graph after running guiding assistant and star cross test show good  west to east patterns but the cross shows the scope is making insufficient moves particularly in south direction (not crossing west east line ) See picture

I have got some guide logs for this evening  see link https://openphdguiding.org/logs/dl/PHD2_logs_W6yr.zip

I did try a calibration step setting of 2500 during the first calibration but dropped it to 1500 because of too few a steps warning

My hand controller/paddle was 2x guide speed. How important is this to match the 0.5 default in PHD2 

In start test, Guide Speed did make a difference. What do you recommend. Currently set at .60

I'm experimenting  with backlash settings in hand controller. What would you suggest for better north south correction?  Unfortunately clouds rolled in before I could get any conclusions but i did see enough to conclude my scope was more responsive in PHD2 tests. Currently 250 in dec and 100 in Ra  i think

[bw_m...@earthlink.net]

Hi Jon.  This is a bit of a mess and rather hard to disentangle.  There are two basic problem areas: 1) operational mistakes that you’re making and 2) significant limitations with the mount.

 

Operationally, you should get back to basics and avoid making things harder:

1. Don’t switch cameras in the same PHD2 profile.  You were switching between the simulator (what are you doing with that?) and your real camera.  Make separate profiles for each unique combination of equipment – use the new-profile-wizard to do that.
2. I don’t know why your camera isn’t recognized for what it is.  I suspect you aren’t running the latest version of the QHY camera drivers – so try that and see if you can use the native driver for the camera.
3. Assuming you have to use the ASCOM camera driver, why are you binning?  This results in a guider image scale that is very coarse and will limit guiding results if you eventually get things working.  The only reason to bin this is if you simply can’t get guide stars any other way.
4. You should enable multi-star guiding and always let PHD2 choose the guide stars.
5. The guide camera appears to be poorly focused, something the Guiding Assistant is complaining about.  You should work on that using a technique that provides definite feedback on the results – the PHD2 Star Profile tool, another app like SharpCap, or even a Bahtinov focusing mask. You can’t do this effectively just doing it by eye.
6. Your polar alignment is really bad, too poor for reasonable guiding, and something else the Guiding Assistant is complaining about.  You should physically adjust the mount to get polar alignment error of around 10 arc-min or so.  Use one of the polar alignment tools to do that.
7. You’ve changed the default guide algorithms – with this mount, you shouldn’t do that.  Leave the Dec guide algorithm at Resist-switch and for that matter, leave everything at their default values other than what the Guiding Assistant advises.  All of your problems are with the mount at this point so fiddling around with guiding parameters is futile.
8. When you do a calibration, you need to manually clear the Dec backlash which is huge.  Start PHD2 looping, then use the hand-controller to move the mount north (‘up’ button) until you see the stars in the display clearly moving.  Then start the calibration from there.  Once you get a reasonable calibration, keep using it, at least for that night.  If you’re not very familiar with gear backlash, there’s an explanation here: https://openphdguiding.org/man-dev/Supplemental_Info.htm#Common_mount_problems
9. You shouldn’t be stabbing in the dark for the correct calibration step-size.  Set the mount guide speed via the hand-controller or mount driver to a known value – in your case, the higher the better to help deal with the Dec backlash.  Once it’s set, leave it alone.  Then rebuild your profile using the new-profile-wizard and tell the wizard what the guide speed setting is.  Your mount driver is very limited, so it doesn’t report guide speeds or even side-of-pier.  But if you get the guide speed settings right, you should be able to get better calibrations.
10. With this much Dec backlash, you will need to learn how to do uni-directional Dec guiding.  That topic is covered in the user guide (right next to the explanation of Dec backlash) and should allow you to guide with this mount despite its limitations.
11. Don’t fiddle around with RA backlash settings in the mount.  Backlash in RA is irrelevant for guiding because the RA drive is never asked to reverse direction.  But if you set backlash correction for RA, you will probably introduce a bunch of unwanted problems for guiding.  You may have no choice but to use a mount backlash setting for Dec but that will open the door to continuous oscillations in Dec that will never stabilize.  If you start using uni-directional Dec guiding, you shouldn’t need to do this.

 

Considering the limited capabilities of the mount, I think you can get better help on a Vixen-specific forum.  For example, it seems there is particular sensitivity to the version levels of the mount firmware:

 

https://groups.io/g/vixen-ss2k/topic/82424305?p=Created,,,20,2,0,0::recentpostdate%2Fsticky,,,20,2,0,82424305

 

It looks like some people have been able to make this thing work acceptably so hopefully you can too.  Obviously, improving the Dec gear mesh would be a first step but maybe that’s not possible. 

 

Good luck,

Bruce

 

For Dec backlash, enable auto backlash compensation, set the value to around 1200 and max 2500. It will be a start to see if you can tame this. But again, you won't 

 

Finally it appears you have something mechanically wrong or possibly cables snagging on your dec: you can see it make a massive >30" move without any reason, indicating something instantly shifted. That's something you should track down. There are other examples as well of this. 

 

To view this discussion on the web visit https://groups.google.com/d/msgid/open-phd-guiding/5bbb839d-9fee-4037-b6a1-d96cc561fb02n%40googlegroups.com.

[Jon Clarke]

hi Bruce/everyone

Success i think! A little problem with insufficient pulse commands warning during calibration but didn't affect guiding which was steady. i actually got some south movements in backlash graph. I followed all of Bruce's advice including creating a new profile and matching my mounts' guide speed with what is set in PHD2. I did set my Dec backlash higher in the handset because of my huge backlash problem and I think i have a value now according to Guiding Assistant backlash calculations. I,m hoping Bruce will tell me what to do to avoid pulse warnings and what this backlash value tells us. The only thing I couldn't successfully change was the camera as I couldn't get QHY camera's settings working so back to ASCOM QHY driver. Oh and i did re-do my polar alignment with the help of APT (which i would recommend as a Image capture programme and it's polar alignment tool). Guiding was good even before i used this tool so I cant say this was the main cause of what caused the improvement. More log files here https://openphdguiding.org/logs/dl/PHD2_logs_gvuH.zip

Many thanks 

Jon

[Jon Clarke]

Still not quite there. As before I get the PulseGuide commands to mount warning 

[Jon Clarke]

Im still getting Pulse Guiding failure to mount warning but calibration still completes but with errors. Why am i getting this warning when it does work to a degree? Guiding was choppy but did settle down later in the evening after a few more adjustment made from guiding assistant. I'm still not sure why it still jumpy in RA (perhaps i should reduce the backlash setting in SS2K handset  which i left high because of insufficient corrections?) I must confess to some alterations to calibration step size but guiding settled down late evening. Please have a look at these logs https://openphdguiding.org/logs/dl/PHD2_logs_ncWM.zip

Thanks in advance

Jon

[mj.w...@gmail.com]

Hi Jon

1.  You spent most of the time with large Polar Alignment errors, 

Better towards the end, but you should have got it right from the onset instead of forging ahead with it poor.

Please explain how you are Polar Aligning.

Polar Align, then Star Align, then Calibrate, then Guide Assistant, then Guide.

2.  You spent 90 minutes with an exposure of 10ms ? Was this you experimenting during dusk ?

3.  The best Cal step size you tried was 1000ms, which gave a Cal in 12 steps.

4.  You often forgot to clear Dec Backlash before Calibrating

5.  At one point you switched to Dec guide mode = south, but as Dec was drifting south, you needed to guide north to correct the south drift.

Michael

Wiltshire

[Jon Clarke]

Ive taken the gear section of my motor and found out why it was ceasing and tightened the bush on the spindle. Ive got the best guiding for a long while. I also got a backlash calculation from running Guiding Assistant (before it hardly completed because south correction was poor) The log file says "Backlash is >= 89960 ms; you may need to guide in only one Dec direction (currently South)"  It also takes ages to complete the calibration and backlash calculation. Can someone explain what is going on and advise a setting to speed the process up without losing the important backlash calculation. 

https://openphdguiding.org/logs/dl/PHD2_logs_JMsk.zip

Thanks Jon 

[Bruce Waddington]

You’re still working with a polar alignment error that is too large, something like 25 arc-min.  It looks like that concern was raised several weeks ago by Michael but you never responded to his questions.  The too-large polar alignment error creates a large amount of Dec drift and that means that calibration and the backlash test are being forced to fight the drift, essentially having to “swim upstream”.  You should learn how to use the PHD2 drift alignment tools and get this problem put to bed before trying to deal with the other issues. Because of what appears to be a huge amount of backlash or stiction in Dec, it is imperative that you manually clear the backlash before starting a calibration.  That will have to be done every time.  With PHD2 looping guide cam exposures, use the hand-controller to move the mount north (‘up’ button) until you see the stars in the display clearly moving in the same direction.  Then start the calibration.

 

Good luck,

Bruce

To view this discussion on the web visit https://groups.google.com/d/msgid/open-phd-guiding/eeeb14eb-ae76-4252-baeb-cd5c1ba57482n%40googlegroups.com.

[Paul Goelz]

I know this sounds like a dumb question, but please bear with me....

When I perform a calibration, it looks like PHD2 begins with "clearing
backlash". This appears to continue until the stars start to move, the
same as if I nudged the mount north. If this is true, why is it advised
to MANUALLY clear backlash BEFORE beginning calibration? Does the time
the mount spends "clearing backlash" affect any subsequent measurements?

There is a practical reason for my question. I operate the scope from
indoors and when I calibrate I am generally not at the scope. I have
found NINA is a bit funky when it comes to manually slewing so it would
be a lot easier to let PHD2 clear the backlash.... like it appears to do.

Paul

--
Paul Goelz
Rochester Hills, MI USA
pa...@pgoelz.com
www.pgoelz.com


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Paul Goelz
Rochester Hills, MI USA
pgoe...@gmail.com
www.pgoelz.com

[Bruce Waddington]

I only advise this when people are having problems and complaining about Dec-related guiding issues or calibration alerts. The backlash in some mounts can be huge. The Dec backlash-clearing phase of calibration works fine for the majority of mounts and if yours is among them, there's no reason for you to pay attention to the advice. Although the backlash-clearing phase of calibration has been made more aggressive over the years, there's only so much it can do because it's operating at guide speed and we don't want to lose the guide star. When people use the hand-controller, they are typically moving the mount at many times the sidereal rate so the backlash is cleared that much more quickly.

That said, I don't understand why your use-case is such a problem. Let's assume your mount does have a lot of backlash and you need to clear it manually. If your setup doesn't change from one night to the next, there's no need to recalibrate so you wouldn't have the problem. If the setup does change, you're presumably already near the scope and you could just do a calibration manually, the same way you would be doing polar alignment or other once-per-night activities. Bottom line, why are you doing calibrations via NINA?

Regards,
Bruce

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[Paul Goelz]

On 2/28/2023 12:25 PM, Bruce Waddington wrote:
> That said, I don't understand why your use-case is such a problem. Let's assume your mount does have a lot of backlash and you need to clear it manually. If your setup doesn't change from one night to the next, there's no need to recalibrate so you wouldn't have the problem. If the setup does change, you're presumably already near the scope and you could just do a calibration manually, the same way you would be doing polar alignment or other once-per-night activities. Bottom line, why are you doing calibrations via NINA?
>
> Regards,
> Bruce

I'm not really "doing calibration via NINA". What I was referring to
was the fact that if I am not by the scope, I do not have an easy way to
nudge the scope except for the slew buttons in NINA. And since I rarely
use them, they have always been a bit confusing as to direction, speed
and whether they are sticky or not. However, I had forgotten that I
could invoke the hand controller in the web interface and do it that way.

No, I don't calibrate every session. Far from it. Unless I disassemble
the image train or change focal lengths (I guide with an OAG), maybe
once a season is more like it ;)

When I am at the scope (like for polar alignment with Polemaster), it is
just me standing there holding a laptop. I don't set up a table or
anything to set things on so holding the laptop and also manipulating
the hand controller is cumbersome enough that I prefer to calibrate from
the comfort of my couch if possible ;) Since my backlash is currently
in the 2500mS region, I guess that means I don't need to bother with the
manual "clear backlash" step.

While we're at it, here's a simple feature request.... how about adding
an option to slew to the celestial equator as the first step in
calibration? I know you can get there from (I think) the drift align
function but it would be really handy to be able to tell it to calibrate
and have it slew automatically if that option was selected. ??

Another minor eature request.... add a backlash compensation display to
the guiding graph?

Paul
--
Paul Goelz
Rochester Hills, MI USA

pgoe...@gmail.com
www.pgoelz.com

[Bruce Waddington]

I'm just finishing the implementation of a "Calibration Assistant" that will address your request along with others - slewing to a suitable location, clearing of backlash, adjustment of any calibration parameters that have become mangled, monitoring of calibration results, and explanation of any exceptions. The feature will appear in the next dev release.

Backlash compensation corrections are just big guide pulse commands so they are already shown on the guiding graph and in the graphs produced by PHDLogViewer.

Regards,
Bruce

-----Original Message-----
From: open-phd...@googlegroups.com [mailto:open-phd...@googlegroups.com] On Behalf Of Paul Goelz

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[Jon Clarke]

Hi Bruce 

If you would like a guinea pig to try out your calibration assistant I would love to give it a try. I'm still getting insufficient move errors. I've redone polar alignment but need to give it a test run. When I north correct using the manual guide buttons in Tools I don't see any movement even with multiple pushes and have to resort to hand controller. What sort of pulse figure should I use in backlash compensation settings? 

Regards

Jon 

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