Re: Mount not working with PHD2 #EXOS2 #ASCOM #astrophotography #pmc-eight



No need look at the logs.  Wireless is convenient for visual users, but for astrophotography users, it's a "siren song", best avoided.

I'd suggest that you get a serial-usb cable with an FTDI chip, and go serial between the laptop and mount.

When you are guiding, you are constructing a near-real-time, closed-loop control system. 

Which is better, to include a communication layer in that loop that can have packet dropouts, latency, and even outright drops, or to use a high speed cable that is very reliable? Lots of posts on that here.

The visual user will seldom notice small reliability issues from wireless, but someone trying to guide, probably will.  You may find examples of people who have made wireless guiding work (there is one I know of), but they will be exceptions. 

Wireless for convenience, but cable for reliability when guiding.

Hope this helps! 

- Bob

On Thu, Mar 25, 2021, at 16:41, Vlad Gherman wrote:
Hello everyone,
I've started astrophotography in September last year with the following setup: 
Telescope: WO ZS 61
Mount: EXOS-2 PMC8 (wireless connection to the laptop)
Camera: ASI1600MM Pro
Software: APT/N.I.N.A
Had no problem with this equipment, taking mostly 60s subs (rarely 90s with round stars) without guiding.
So...heading to the problem...
Recently bought an ASI120mm camera with an Artesky guidescope. On the first night with this setup, I've managed to take approx. 5x300s in N.I.N.A. After that my mount got suddenly disconnected and then PHD2 never worked properly.
I'm struggling for more than 2 weeks...
Having the following issues on different nights:
1. PHD2 error messages:
- pulse guide command to mount has failed
- RA calibration failed star did not move enough
- PHD2 is not able to make sufficient corrections in RA
- PulseGuide command to mount has failed - guiding is likely to be ineffective
- Although I start calibration within +/- 10 degrees of celestial equator I get the following message: "Calibration this far from the celestial equator will be error prone. For best results calibrate at a declination of -20 to +20."
 2. The most recent one that happened 2 nights in a row without any error messages is that PHD2 loops infinitely when I start calibration. 
Tried the following "fixes":
- increasing calibration steps in PHD2
- using another USB Type-C cable (tried connecting guide camera to imaging camera and also tried connecting guide camera directly to the laptop)
- tried different USB slots
- rebalancing
- reinstalling all the software (ASCOM drivers, PHD2, N.I.N.A, APT, ZWO drivers)
I'm hopeless...
You can find my last PHD2 logs in the attachment.
Not sure if this is a mount issue that doesn't receive commands or a PHD2 issue.
I'm opened to any ideas, suggestions. 
Thank you in advance!

  • PHD2_DebugLog_2021-03-24_201800.txt
  • PHD2_GuideLog_2021-03-24_201800.txt

Mounts: ES PMC-8 EXOS2, Serial
Scopes: SW 130P-DS, SV 102EDT, ZWO 60/280 Guide
Cameras:  Nikon D5300, Altair GPCAM2 290M
Software: ASCOM 6.3, CdC, AstroTortilla, BYN Pro, Sharpcap, PHD2
Computer:  Thinkpad x230, Win7Pro/64

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