Primalucelab PhD2 with Vixen SB10

[VT]

Hi,

I am using a Primalucelab Eagle to control my Vixen Starbook 10 using Ethernet port on SXP2 mount. I am using 50mm guide scope with ASI120MC camera. I am consistently failing to guide with an error of too few points. I used to guide when I connected by ST4 cable from the camera to SB10. Can you help me troubleshoot the issue? Thanks a lot in advance!

The log for this issue is below.

https://openphdguiding.org/logs/dl/PHD2_logs_HM5W.zip

Regards

VT

[Bruce Waddington]

I'm afraid you've created a mess with your configuration parameters.  The focal length of your guide scope is not 50mm - that's the diameter of the objective lens.  The focal length is probably more like 165mm but you should find the correct value - don't guess.  Once you've figured this out, update to the last PHD2 dev release, 2.6.11dev6:

https://openphdguiding.org/development-snapshots/

Then run the new-profile-wizard and create a new configuration profile.  Be sure you enter the correct guider focal length and the mount guide speed.  Your mount driver isn't reporting the guide speed value so you will need to find that out as well.  It's probably 0.5x sidereal but you should look into it.  Then build a dark library, it doesn't take very long and it doesn't pay to cut corners.  At this point, your only goal is to get a good calibration.  To do that, run the new Calibration Assistant and follow all its instructions - don't try to out-think it.  It will start by slewing your scope to an optimum location - not at high declination regions like you were doing.  Once you have an acceptable calibration - the CA will tell you - you can move ahead with imaging and guiding.  You should probably also review the Best Practices document to avoid other common mistakes:

https://openphdguiding.org/phd2-best-practices/

If you're new to ASCOM guiding, remember that you won't have to recalibrate every time you slew.  As a beginner, you might want to calibrate once at the start of each night's session assuming you don't have a permanent setup.

Good luck,

Bruce

[VT]

Hi,

I took your advice and I have fixed my focus number (thanks for pointing it out). I am still seeing >2" of error. Can you help me understand how to change the sidereal rate? Also, after a meridian flip my calibration and SGPro went completely bonkers and was not able to track at all. Is there anything special I need to do? Please see the below logs. Thanks.

https://openphdguiding.org/logs/dl/PHD2_logs_qc9w.zip

Regards

VT

[Bryan]

VT

Setting the guide speed as a fraction of sidereal is on the second page of the New-Profile Wizard.

Bryan

[VT]

Bryan,

The tracking doesnt seem to work after meridian flip. It keeps getting to star lost. I have SGP and Vixen SXP2 mount.

https://openphdguiding.org/logs/dl/PHD2_logs_7Xmf.zip

Regards

Vinny

[Bruce Waddington]

Your problem is that can't get a decent quality calibration which was the reason you were seeing all the alert messages warning you about that.  In my first response, I asked you to upgrade to the 2.6.11dev6 release (link in original response) and start using the Calibration Assistant.  You didn't do either of those things so you really didn't make much progress.  With regard to the mount guide speed, that is something that is set either in the ASCOM mount driver user interface or via the hand controller.  That depends entirely on the details of your mount, not something we can tell you.  It looks like the mount is currently guiding at 1x sidereal, which is fine, so you can leave it alone.  But that means when you run the new-profile-wizard - again, on 2.6.11dev6 - you should tell the wizard that the mount guide speed is 1x sidereal.  Your mount driver doesn't report the guide speed which is why this can't be handled automatically by PHD2.  When you get all this done, your only goal should be to get an error-free, acceptable calibration.  Most of the calibrations in your latest log were terrible so it's no surprise that guiding didn't go well.  I suspect you are also using a rather flimsy, stalk-mounted finderscope for guiding.  Those are very prone to introducing lots of guiding problems because they aren't rigid enough.  If your guide camera shifts around by 4 microns - that's 1/10 the thickness of a human hair - it will introduce a very large tracking error.  Everything associated with that guiding assembly must be very tight, very rigid, and not subject to any kind of tugging from cables.

Good luck,

Bruce

[VT]

Bruce,

I took your advice and ran the calibration assistant. After some trouble for doing it the first time, I think I have gotten it to work. My results are only slightly better. Can you please look at the results and comment? I have a theory that I wanted to run by you and see if that is a potential issue. I am using a small guidescope sitting on a finder shoe. Just to the right of it there are some intermittent flahing LEDs (Red color) from my Primaluce lab Eagle. I am seeing the guide stars image background brightness fluctuate over time at random intervals. Could this be a factor in impacting the guiding leading to unnecessary moves? Thanks.

Regards

Vinny

https://openphdguiding.org/logs/dl/PHD2_logs_zQD2.zip

[Bruce Waddington]

Hi Vinny.  I'm sorry, it's really hard to pinpoint what's wrong but there's something definitely wrong with your equipment setup.  As I said in my previous message, these stalk-mounted finder scope arrangements are just a bad idea because they aren't rigid enough to support the guide camera and the cables as the scope moves around in the sky.  Having a light source right next to it is obviously a bad idea but I doubt that's the source of your problem.  Operationally, when you finally get a good calibration, keep using it - what's the point in doing them over and over again?  If you set up and tear down each night, try to get one good calibration at the start and use it for the rest of the night.  How careful have you been about cable routing?  Perhaps you should send us a photo of what your guiding rig looks like including the cables.  I don't have any idea what mount you're actually using and what its weight capacity is - is it overloaded?  What kind of surface is your gear sitting on?  If possible, it would probably be more efficient if you could get some on-site help from someone who is experienced in astro-imaging and could examine your physical setup.  Trying to do this remotely has its limits when the problems really don't have anything to do with guiding.

Bruce