Pegasus Astro NYX-88 mount, also an issue with calibration, to be continued

[Philippe ANGERS]

Hello,

I'm starting this new thread in order to analyze what has been done yesterday and find out if most of the issues have been solved or if there're still things to fintetune.

The previous thread was this one : 

- Help needed with my new Pegasus Astro NYX-88 mount, also an issue with calibration

Here's the link of last night session, certainly more helpfull to analyze my mount behaviour :

- https://openphdguiding.org/logs/dl/PHD2_logs_5Y87.zip 

There is still room for improvement in terms of focus, which should have a slight impact on the shape of the stars and, as a result, on the stars as they are provided by the OAG to the guide camera.

Last night was clear, but not exceptional. Can we already draw some conclusions?

This time, the guiding was more like normal guiding.

Thank you in advance for your analysis and suggestions.

Philippe

[pollya...@gmail.com]

Hello Phillipe,

In your calibration step, you set . . . 

Assume Orthogonal Axes = yes

This seems unwise to me, bu t I'm sure the experts will comment more.

Cheers,

- Jack T

[Philippe ANGERS]

Hello Jack,

Ouch, you may be right, I think that Bruce (or someone else)  mentioned this in his recommandations in my previous post...

However, I don't know what's the impact of this setting on the whole calibration process...

Philippe

[Brian Valente]

>>>However, I don't know what's the impact of this setting on the whole calibration process...

It can be significant, but there's no way to tell until you run a calibration with this disabled. 

Instead of PHD measuring your actual orthogonality, it's a 'cheat' saying "just assume the axes are perfectly perpendicular. That may or may not be entirely true, but yes you should follow Bruce's prior recommendation and disable it.

Generally imo you should never use 'assume axes orthogonal' unless you have a legitimate reason for doing so. 

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[Philippe ANGERS]

Ok, I will uncheck this option for the next clear night!

Too bad I forgot this setting...

Clouds came in today, so, it's a no-go for tonight...

Philippe

[Bruce Waddington]

It looks to me like you haven't made any progress with your camera-related issues so you are still being hampered by too many lost-star events and too few usable guide stars.  That said, you were able to get enough of a workable guide session starting at 21:39 for us to get some insight.  Unfortunately, that looks very much like the problems we found in an earlier post for the same mount:

https://groups.google.com/g/open-phd-guiding/c/cND5EGAKVO8

It's a big disconcerting that we have back-back situations with the same mount and the same very large periodic error in RA.  Here's what yours looks like:

So it's a nearly identical case of a 40 arc-sec peak-peak tracking error with a period of around 430 seconds.  You can see this error imprinted on the native tracking performance during the night:

So, again, this will need to be taken up with the mount manufacturer.  

As Brian said, checking the "assume orthogonal" option is just a feel-good band-aid.  It means you won't see an alert about orthogonality error, but the error is still there.  The only difference is that we won't know how bad it is.  The error is caused by the large amount of periodic error that causes the RA axis to be going "too fast" or "too slow" depending on where it is in the phase of the sine-like periodic error.  Since you have no way to know what the gear phase is, there's no way to do a calibration only during the brief periods when the RA axis is tracking accurately.  

Regards,

Bruce

[Ventura Valderrábano Ornedo]

Thanks you.

I will send this data to the retailer and then to the manufacturer. 

Regards.

Ventura Valderrábano Ornedo 
ventura.a...@gmail.com 

+34 607142000

To view this discussion visit https://groups.google.com/d/msgid/open-phd-guiding/3e138cdd-dc4b-43d3-93ee-50bde496c58an%40googlegroups.com.

[Philippe ANGERS]

Hello Ventura,

That would be nice, because George KARANTZALOS from Pegasus Astro support, with whom I used to exchange since buying the mount for pre sale advice, since last summer, doesn't want to reply anymore and is probably convinced that I'M the problem an NOT the mount...

A month ago, he told me that Pegasus would accept a return of the mount BUT, if they find out that I misused the mount, after all their tests listed in a PDF file, I would be charged 250 euros + shipping back !!!

And you can understand that I can't take the risk of that...

The reason why I needed and still need the analysis of experiemented people.

My retailer in France is Pierro Astro, and he won't do anything regarding the mount except trasnfer my mail to Pegasus...

I sent to George an email this morning with Bruce analysis.

Philippe

[Philippe ANGERS]

Hello Bruce,

I have taken a look at ToupTek reply earlier in January when I sent an email to explain that I couldn't use their driver labeled "ASCOM" (see screenshot below), as the Gain value in PHD2 is grayed out, and I have kept using the other "ToupTek Camera" with very few settings just "8bits or 16 bits" but at eatI could change the gain in PHD2.

They were saying agin that ilictly either I was the problem and not their camera or the... mount !

Anyway the mount is not responsible of the fract that this field is locked and I can't change gain...

Changing fgain from 0 to 100 on their driver GUI before using the camera in PHD2 didn't change anything for the image in PHD2...

Not to mention the beginning of their explanation, which I still don't understand...

Here's waht they were replying :

<tpa-s...@touptek.com> 2026-01-04 09:19:36(GMT+08:00)写道

Regarding input values: the gain range in PHD2 is 0–100, corresponding to 100 to the maximum gain value in Toupsky. Therefore, the gain setting in PHD2 can be understood as a percentage—i.e., "using x% of the maximum gain." The gain value in the ASCOM driver follows the same principle.

Any settings made in Toupsky have no relationship with the settings when connecting the camera in PHD2. The failure to calibrate may stem from the mount. If you can see star points in the image, the inability to calibrate is most likely due to the mount or other settings.

If you find that the gain or other settings in PHD2 are grayed out, it is likely because your camera is in a looping exposure state, during which PHD2 does not allow the user to modify certain key settings. You need to stop the exposure, verify that the parameters in the gain and calibration calculator are correct and reasonable, and then restart the exposure.

Additionally, if you see a "not enough movement" prompt in PHD2, you can try increasing the guiding rate in the mount control settings.

[Bruce Waddington]

Ok, let's come back to the camera problem.  You haven't uploaded the PHD2 logs when you were trying to use the ToupTek ASCOM driver so I'm having to guess here.  Based on the screen shot, I don't think you're connected to the ASCOM driver, I think you're connected to the native driver.  Did you separately download and install the ASCOM driver.  That's not the same as ToupTek Sky or any of the other ToupTek apps, it's a separate piece of software that must be downloaded from their web site and installed.  In PHD2, the ASCOM drivers are identified by '(ASCOM)' in the name and I don't see that in your screen shot.  If you get that sorted out, then you should be able to use the ASCOM driver gain control successfully.  Going forward, you must upload your PHD2 log files for this sort of thing regardless of whether you actually did any guiding.

Bruce

[Philippe ANGERS]

Hello Bruce,

I would like to, but as explained in my previous post, when I'm using the ASCOM ToupTek driver, first the Gain field in PHD2 is locked (grayed out), and second, the background from the camera is so grainy that I cannot distinguish stars!

I've been told there that it's not very important, because it's more advised to use Star prfile to help focusing.

Was it grainy and unexploitable compared to the image from the other ToupTek driver with the which the background is almost black and I can see the stars, be they properly (I didn't say perfectly ! ;-) ) focused or, conversely, defocused and looking like donuts!!

Here's what I get with the ToupTek driver I'm currently using (let's forget the other data):

And here's what I would get with the other (let's forget again messages and figures):

Of course, the most important is the HFD figure, but is this normal to get a very grainy image everytime?

One more question, the gain : I can't change it in PHD2 and whatever the value selected in the ASCOM ToupTek driver GUI, it doesn't make any difference on the image displayed in PHD2, and the gain field is permanently locked, what make me think something is not communicating properly between the driver and PHD2...

When I asked them an explanation, they replied with the cryptic explanation mentioned above!

Do you undestand what they mean, because, I don't!

Philippe

[pollya...@gmail.com]

Hello again Phillipe,

I suggest you also install the 32bit (x86) Touptek native driver.

Cheers,

- Jack T

[Philippe ANGERS]

Hello Jack,

What would adding the 32 bits driver in a 64 bits operating system, bring ?

Philippe