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Mount stops tracking after PHD2 starts guiding

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#1 Astro_Sholo

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Posted 26 June 2019 - 10:09 PM

Hello all,

 

As a disclaimer I want to say that I'm very new to guiding and go-to in general as I just upgraded from my tiny skyguider pro. 

 

I've recently purchased a CEM25P, WO 50mm guide scope & ASI120mm-s guide camera in an effort to begin guiding.  A few nights ago I had set everything up and was able to get nice round stars at 5 minute exposures guided using my WOZ61.  Tonight, after I set up and selected my target I began to run into a an issues in PHD2.  After framing my target and doing a test to make sure that M3 stayed in the frame, I began to guide.  I noticed that PHD2 acknowledged the existing tracking of the mount for about 1 second but then suddenly dropped off (graph) in both DEC and RA and I began to see both the guide star and target drift out of frame.  PHD2 then informed me to check my ST-4 cable for snags because it was unable to make DEC corrections. (I run computer to ASI120, ASI120 to Mount).  After unplugging all cables and resetting my computer/mount/cameras I was left with the same problem.  What I'm left to assume is that PHD2 is somehow overriding the mount to stop tracking and therefore can't get a good lock on the star?  I'm not really sure as to why the mount or PHD2 aren't recognizing each other.   

 

Any help is greatly appreciated!

 



#2 kisstek

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Posted 26 June 2019 - 10:20 PM

Most of us hook our's up with computer to guide camera and computer to mount. That way the computer (PHD2) can send the pulse commands directly to the mount. It'll also come in handy later when you want the computer to do meridian flips and plate solving.


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#3 jerahian

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Posted 26 June 2019 - 10:57 PM

+1 to kisstek's recommendation.  Definitely move away from using the ST-4 cable and connect PHD2 directly to the mount for pulse guiding.

 

Also, I'm not 100% sure about this, but I believe you need to recalibrate for every new target position when you use the ST-4 cable, because PHD2 is not aware of the mounts actual position when using ST-4 guiding.  This may have been your issue if you didn't calibrate/recalibrate PHD2 after you slewed to M3.

 

-Ara



#4 scadvice

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Posted 26 June 2019 - 11:50 PM

+2 and adding to Ara's post

 

Also, as you start PHD2 hold the control key down. This will re-calibrate PHD2 to your guide camera. If you are setting up and tearing down each session it's possible you rotated the guide camera and that will mess things up as PHD will not know the correct directions to move when tracking.



#5 Astro_Sholo

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Posted 27 June 2019 - 06:15 AM

Most of us hook our's up with computer to guide camera and computer to mount. That way the computer (PHD2) can send the pulse commands directly to the mount. It'll also come in handy later when you want the computer to do meridian flips and plate solving.

 

 

+1 to kisstek's recommendation.  Definitely move away from using the ST-4 cable and connect PHD2 directly to the mount for pulse guiding.

 

Also, I'm not 100% sure about this, but I believe you need to recalibrate for every new target position when you use the ST-4 cable, because PHD2 is not aware of the mounts actual position when using ST-4 guiding.  This may have been your issue if you didn't calibrate/recalibrate PHD2 after you slewed to M3.

 

-Ara

 

 

+2 and adding to Ara's post

 

Also, as you start PHD2 hold the control key down. This will re-calibrate PHD2 to your guide camera. If you are setting up and tearing down each session it's possible you rotated the guide camera and that will mess things up as PHD will not know the correct directions to move when tracking.

Thanks guys! Will definitely try these things out.  What is the best connection from mount to computer? Would I connect the cable from the computer to guide port or handbox?  Also would this force me to use a program like stellarium or would the changed connection simply be enough?

 

In other words, would I have to then control the mount via the computer instead of handbox? 


Edited by Astro_Sholo, 27 June 2019 - 06:20 AM.


#6 mewmartigan

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Posted 27 June 2019 - 08:54 AM

For the CEM25P you need a serial to USB adapter. The mount should have come with a 4 pin phone jack lookin' cable with serial on the other end. This plugs into the handbox. Serial connects to the computer via the USB cable then.

 

You'll install the iOptron Commander software (and driver and ASCOM platform) to get the mount and the computer talking and then in PHD2 you can select the iOptron driver for the mount connection.

 

At that point you can control the mount with the handbox or through the computer. 

 

EDIT: The only cable coming from your autoguider then would be the usb cable to the computer. No ST4 cable necessary.


Edited by mewmartigan, 27 June 2019 - 08:57 AM.

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#7 scadvice

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Posted 27 June 2019 - 11:21 AM

Two helpful videos:

 

The short one:

 

https://www.youtube....h?v=Mt0luBLaHDw

 

The loooonge one:

 

https://www.youtube....Rta98rs&t=3667s



#8 kyle528

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Posted 27 June 2019 - 11:50 AM

It sounds like you may have calibrated PhD the first night on one side of the meridian, and was attempting to guide the second night on the other without PhD knowing it was on the other side. It may have been attempting to send pulses in the opposite direction of what it needed to. This exact thing happened to me my first couple nights guiding. Calibrate before each guiding session, and re calibrate after a meridian flip, or tell PhD to flip directions after a flip, whichever your acquisition software prefers (apt does a re calibration after a flip).


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#9 Alex McConahay

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Posted 27 June 2019 - 05:36 PM

.

EDIT: The only cable coming from your autoguider then would be the usb cable to the computer. No ST4 cable necessary.[/quote]


Besides the cable downloading the pictures and controlling the guide camera.

Alex
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#10 Astro_Sholo

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Posted 27 June 2019 - 07:33 PM

For the CEM25P you need a serial to USB adapter. The mount should have come with a 4 pin phone jack lookin' cable with serial on the other end. This plugs into the handbox. Serial connects to the computer via the USB cable then.

 

You'll install the iOptron Commander software (and driver and ASCOM platform) to get the mount and the computer talking and then in PHD2 you can select the iOptron driver for the mount connection.

 

At that point you can control the mount with the handbox or through the computer. 

 

EDIT: The only cable coming from your autoguider then would be the usb cable to the computer. No ST4 cable necessary.

Trying to avoid the serial connection due to the lack of the port on my laptop, I purchased this cable:

 

https://www.amazon.c...0?ie=UTF8&psc=1

 

Hopefully this solves my issues, thanks!


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#11 Astro_Sholo

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Posted 27 June 2019 - 07:34 PM

Two helpful videos:

 

The short one:

 

https://www.youtube....h?v=Mt0luBLaHDw

 

The loooonge one:

 

https://www.youtube....Rta98rs&t=3667s

Great videos! I've already learned so much in 20 minutes.  Thanks!


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#12 Astro_Sholo

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Posted 27 June 2019 - 07:36 PM

It sounds like you may have calibrated PhD the first night on one side of the meridian, and was attempting to guide the second night on the other without PhD knowing it was on the other side. It may have been attempting to send pulses in the opposite direction of what it needed to. This exact thing happened to me my first couple nights guiding. Calibrate before each guiding session, and re calibrate after a meridian flip, or tell PhD to flip directions after a flip, whichever your acquisition software prefers (apt does a re calibration after a flip).


Sent from my iPhone using Tapatalk

Got it.  What was strange that I had slewed to mulitple targets on both sides of the meridian and experienced the same issue but I'm sure the mount was just confused all together.  Next time i'm going to make sure I re-calibrate if I ever use this method again



#13 mewmartigan

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Posted 27 June 2019 - 08:18 PM

Trying to avoid the serial connection due to the lack of the port on my laptop, I purchased this cable:

 

https://www.amazon.c...0?ie=UTF8&psc=1

 

Hopefully this solves my issues, thanks!

Interesting. Let us know how that cable works out. 



#14 Ballyhoo

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Posted 27 June 2019 - 10:12 PM

Most of us hook our's up with computer to guide camera and computer to mount. That way the computer (PHD2) can send the pulse commands directly to the mount. It'll also come in handy later when you want the computer to do meridian flips and plate solving.

I wonder if it matters at all , for example I use RS232 "guide" but everything hubs from my main imaging camera and from there to the laptop. would that be acceptable for the OP?



#15 Astro_Sholo

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Posted 29 June 2019 - 09:19 AM

I wonder if it matters at all , for example I use RS232 "guide" but everything hubs from my main imaging camera and from there to the laptop. would that be acceptable for the OP?

I ended up not going for that type of connection and went directly from the mount to computer using the serial cable instead.  The mount ended up responding much better



#16 Astro_Sholo

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Posted 29 June 2019 - 09:28 AM

Interesting. Let us know how that cable works out.

Marcus, just noticed that we have a similar setup laugh.gif  One of these days I'll upgrade from my DSLR to a dedicated..
 
 
Anyhow, guiding using this cable works BEAUTIFULLY.  I've attached a capture of my PHD graph from last night.  After a few hours of fiddling with settings and getting myself adjusted with the software, I was able to get 5 min. subs for 3.5 hours with no issues at all

Attached Thumbnails

  • Capture.PNG

Edited by Astro_Sholo, 29 June 2019 - 09:29 AM.


#17 mewmartigan

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Posted 29 June 2019 - 01:12 PM

Good deal! I have my serial cable wrapped up and secured to the tripod spreader. Removing it from the equation is nice though.
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