Testing Connections with the Manual Guide Tool

[wave...@talktalk.net]

Seems like this is the Season of Wierd.
In recent weeks I've been managing to guide below 1" RMS with my 10" LX200 Classic (F6.3 Reducer) and an OAG. This uses an ASI120 mono camera, Binning 2.
The PHD2 (v2.6.9dev4) setup is:
Mount - on Camera (via the 'CCD' (ST4) port)

Aux Mount - ASCOM/Meade driver (via the RS232 serial port)

I'm now having issues with the guide pulses, which don't seem to be getting to the mount. Even though PHD2 sends the corrections, the mount is unresponsive, It's effectively running unguided.

My attention was initially focused on the ST4 system, which I can test in daylight using the Manual Guide tool.
Running the test at say 5000ms pulse, I could easily see the mount responding in all four directions at the arcsec level using the Handset / Scope Coordinates screen. That no longer happens. Swapping out the ST4 cable with two others makes no difference.

The laptop I use for guiding also holds the Stellarium application. If I shut down PHD2 and immediately after, run Stellarium, it connects to the mount using the same ASCOM/Meade driver and will slew the mount to on-screen targets as normal. This verifies the RS232 connection.

The 'CCD' (ST4) port on the mount has been verified Pin by Pin using a simple grounding of the individual N, S, E, ahd W Pins as described in the Meade literature (MAPUG archive). The Handbox Coordinates screen confirms the mount responds at guide speed in each case.

So, that appears to point a finger at the guide camera/ST4 system.

Will a PHD2 Debug Log help with this issue?

Many thanks for any advice.

- Jack

[wave...@talktalk.net]

I've uploaded the Debug logs from today and yesterday's attempts to diagnose the problem. Hope this works because I'm using a different computer from that in my observatory (shed on wheels).

Maybe these will point to an obvious error? 

Debug Log 1

Debug Lod 2

Cheers,

- Jack

[bw_msgboard]

Hi Jack.  The debug logs don’t help with this because the ST-4 guide mechanism is largely open-loop.  There is no status returned by the mount so there’s no way to know what was done with the guide command or whether it was even seen.  However, the evidence from the timing in the log suggests that “something” was in-process for the expected 5 seconds of your manual guide commands.  I don’t think I’ve ever seen a case where the guide camera was broken in this particular way so I think it’s probably between the guide camera and the mount.

 

When I was using a system that required ST-4 guiding, I bought the inexpensive GP-USB adapter from Shoestring. Astronomy.  That device converts from USB to ST-4 and eliminates the guide camera guiding functions and also a cable that has to move around with the guide camera.  The GP-USB cables connect to the base of the mount and to the PC so they remain stationary.  You should also be sure the mount isn’t in some state where it won’t accept guide commands – in other words, not parked, fully initialized, tracking, all that.

 

Hope you can track it down,

Bruce

 

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[wave...@talktalk.net]

Hello Bruce, many thanks for assessing the logs. I suspected the ST4 system is opaque to PHD2, so it's back to basics I guess. I've looked at the Shoestring gizmo and may consider getting one if it becomes  clear that there's an issue with the guide cam's ST4 stuff. I may also consider a better camera. I'll try using my ASI224 imager in place of the guider and see if the problem persists. I have a funny feeling it will, so replacing the guide cam isn't gonna fix it. Am I correct in assuming the ST4 'dialog' simply involves pulling N, E, S or W pins low?

Cheers,

- Jack

[Brian Valente]

Jack - before you invest a bunch of time and effort on this, is it possible for you to switch to ASCOM/pulse guiding from ST-4?

ST4 is less capable (and more difficult to diagnose) than pulse guiding via ASCOM

Brian

To view this discussion on the web visit https://groups.google.com/d/msgid/open-phd-guiding/79d8ca2d-3436-4ea7-a7f0-5b4f909f563fn%40googlegroups.com.

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Brian 

Brian Valente

portfolio brianvalentephotography.com 

[wave...@talktalk.net]

Hi Brian, the LX200 Classic doesn't accept pulse guiding, which is why I have to use ST4. I think!

- Jack

[Bryan]

Jack

I have a GP-USB from when I was using an old Celestron mount for imaging.  I do not know if the Meade guide port is the same as the Celestron guide port.

It has not been used for years, but should be fine (see attached).  If you are interested, then send me your address at

bcas dot club at gmail dot com

No charge.  I glad someone can use it!

Bryan

[wave...@talktalk.net]

Bryan, I'm overwhelmed by your generosity, thank you so much for your offer.

I am indeed interested, for I fear my camera has lost it's ST4 output, leaving me in a quandry.

A possible snag, I'm in the UK.

I'll email you now.

Regards,

- Jack

[Geof Lewis]

Jack,

Where in the U.K. are you? I think that I have one of those that I used with my old 10”  Meade LX200GPS. I’ll have to find it as I sold the Meade nearly 5 years ago.

Geof

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From: 'wave...@talktalk.net' via Open PHD Guiding <open-phd...@googlegroups.com>
Sent: Sunday, March 7, 2021 9:17 pm
To: Open PHD Guiding
Subject: Re: [open-phd-guiding] Re: Testing Connections with the Manual Guide Tool

 

To view this discussion on the web visit https://groups.google.com/d/msgid/open-phd-guiding/3e60302f-9969-49f4-99d3-9cd55b2d0337n%40googlegroups.com.

[Bryan]

Jack

I leave it to you to choose which unit.  I have no problem sending it to you and have your address from your e-mail. However, if Geoff finds his, then its likely less expensive.

No worries either way

Bryan

[Geof Lewis]

Bryan and Jack,

I’m now wondering whether I’m barking up the wrong tree. Looking back at Bruce W’s suggestion, I see that it relates to ST4 guiding. My DSUSB adapter is a camera shutter control for my Nikon DSLR, which connects to the laptop to allow long exposures greater >30s, so on reflection I’m not sure that is anything to do with ST4 guiding. I recall that I actually used it last year to run some tests on my Nikon D90. I don’t think it has anything to do with Celestron or Meade, but it’s several years since I used it for astrophotography, so my memory is a bit fogged.

Jack,

I live in South Norfolk, U.K., so depending where you are, it maybe possible to lend you mine, but maybe it’s not what you’re looking for, so let me know. Maybe Bryan’s is more what you need.

Sorry, if I’ve caused any confusion, I saw Bryan’s pictures of the Shoestring adapter and thought it was what I have.

Regards,

Geof

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From: open-phd...@googlegroups.com <open-phd...@googlegroups.com> on behalf of Bryan <bcas...@gmail.com>
Sent: Monday, March 8, 2021 12:07 am

To: Open PHD Guiding
Subject: Re: [open-phd-guiding] Re: Testing Connections with the Manual Guide Tool

 

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[Bryan]

No problem, Geoff.  Jack, I will send the GPUSB tomorrow.

Bryan

[wave...@talktalk.net]

Geoff, thank you too for your offer of help. The DSUSB adapter appears to be a shutter control system for running DSLAR cameras. So, unfortunately not related to my problem, but your kind suggestion is most appreciated.

Bryan, that's great, thank you again. Contact me about the postage. I've sent you another email.

Cheers,

- Jack

[Chuck Sterling]

The gpusb is what you have been offered and what you need.

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[Chuck Sterling]

Sorry for my reply before reading further, but in any case I also have an unused gpusb and a dsusb that are available for anyone who can make use of them.

[bw_msgboard]

Hi Jack.  Yes, the ST-4 interface is butt-simple, just voltage changes on the pins.  You can’t assume that the NSEW pins have any particular polarity in terms of direction – that gets sorted out during PHD2 calibration.  Also, some guide cameras can leave a pin in an unwanted state when powered off, so that’s why we tell people to disconnect the ST-4 cable unless they’re actually trying to guide with it.

To view this discussion on the web visit https://groups.google.com/d/msgid/open-phd-guiding/79d8ca2d-3436-4ea7-a7f0-5b4f909f563fn%40googlegroups.com.

[wave...@talktalk.net]

Hey Guys, just to round this off, I tested my rig using the imaging camera in place of the ASI120 mono guidecam and the ST4 system works as expected with the Manual Guide tool. So, seems like an unusual case, which I hope will be resolved by Bryan's generous donation of the GPUSB adapter. Once again, many thanks to Bryan. Meanwhile, I need to find the paperwork for my ASI120 purchase and check if I still have some warranty.

Cheers

- Jack

[Richard Beck]

Jack,

Have you been trying to use the 120 in 16-bit mode?  If so, try using it in 8-bit mode only. 

My 120MM mini would drop to 8-bits silently when I used the 16-bit driver.  When I raised the issue with the INDI folks (I use KStars/EKOS/INDI exclusively), the lead maintainer told me that this was a feature of the ASI 120 cameras and ASI's driver.

[wave...@talktalk.net]

Hi bec...@gmail.com, Yes I have the 16 bit mode set in the Connection Panel / Camera Setup GUI. The centroid detection is better apparently. Could that really disable the ST4 output? Was I actually guiding before this in 8 Bit? I've no idea, but I'll grasp at any straw right now. So, I'll repeat the Manual Guide tests in 8 bit asap and hope for a revelation.

Cheers,

- Jack.